Saturday, January 19, 2013

Generator Protection Types and an Example Settings


The following are the main protection schemes adopted for our generator.

1. Generator Differential Protection
2. Generator & Transformer Differential Protection
3. Loss of Field or Loss of Excitation Protection
4. Negative Sequence or Current Unbalance Protection
5. Over Fluxing or Over Excitation Protection
6. Over Current Protection
7. Stator Earth Fault Protection
8. Rotor Earth Fault Protection (64R)
9. Restricted Earth Fault Protection
10. Backup Impedance Protection
11. Low Forward Power Protection
12. Reverse Power Protection
13. Pole Slip Protection
14. Pole Discrepancy Protection
15. Local Breaker Back Protection
16. Bus Bar Protection
17. Over Frequency Protection
18. Under Frequency Protection
19. Over Voltage Protection


1.GENERATOR DIFFERENTIAL PROTECTION:

Setting : 0.5 Amp Time : Instantaneous
It is one of the important protections to protect generator winding against internal faults such as phase-to-phase and three phase-to-ground faults. This type of fault is very serious because very large current can flow and produce large amounts of damage to the winding if it is allowed to persist. One set current transformers of the generator on neutral and phase side, is exclusively used for this protection. The differential protection can not detect turn-to-turn fault and phase to ground within one winding for high impedance neutral grounding generator such as ours. Upon the detection of a phase-to-phase fault in the winding, the unit is tripped with out time delay.
Relays acted : a. Flag operation at Protection panel.
b. Acting of Master relay
c. Indication at Annunciation Panel.
Consequences : a. Tripping of 220KV breaker
b. Tripping of Field breaker
c. Stop command to Turbine thro’ Mark-IV
Status : a. Unit is at coasting down.

Once the differential protection operated, the unit can not be taken into service unless the generator winding is thoroughly examined by the maintenance staff of any internal faults

2.GENERATOR-TRANSFORMER DIFFERENTIAL PROTECTION :
Setting : 0.75 Amp Time : Instantaneous
It protects 11KV bus duct, 11/0.440KV unit auxiliary transformer, 11/20KV step-up transformer against internal faults such as phase-to-phase and three phase-to-ground faults. This type of fault is very serious because very large current can flow and produce large amounts of damage to the winding if it is allowed to persist. One set current transformers of the generator on neutral side and another set current transformer on 220KV side after transformer, is exclusively used for the protection. Upon the detection of difference in current between these current transformers, the unit is tripped with out time delay.One the generator-transformer differential protection operated, the unit can not be taken into service unless the 11KV bus duct, unit auxiliary transformer, power transformer are thoroughly examined by the maintenance staff for any internal faults.
Relays acted : a. Flag operation at Protection panel.
b. Acting of Master relay
c. Indication at Annunciation Panel.
Consequences : a. Tripping of 220KV breaker
b. Tripping of Field breaker
c. Stop command to Turbine thro’ Mark-IV
Status : a. Unit is at coasting down.


3.LOSS OF FIELD OR EXCITATION PROTECTION :
Setting : K1-2, K2-1, K3-2 Trip after 2 Sec.
When the synchronous machine with excitation, is connected to the grid, it generates reactive power along with active power to the grid and the rotor speed is same as that of grid frequency. Loss of field or loss of excitation results in loss of synchronism between rotor flux & stator flux. The synchronous machine operates as an induction machine at higher speed and draws reactive power from the grid. This will result in the flow of slip frequency currents in the rotor body as well as severe torque oscillations in the rotor shaft. As the rotor is not designed to sustain such currents or to withstand the high alternating torques which results in rotor overheating, coupling slippage and even rotor failure.
A loss of excitation normally indicates a problem with the excitation system. Some times it may be due to inadvertent tripping of filed breaker, open or short circuit of field winding or loss of source to the exciter. If the generator is not disconnected immediately when it loses excitation wide spread instability may very quickly develop and major system shutdown may occur.
When loss of excitation alarm annunciates at annunciation panel, the machine may probably be running with less excitation at leading MVAR power. Increase the excitation on the machine until it reaches on lagging MVAR power. The machine trips on the same protection along with alarm resynchronize the machine and try to stabilize at required MVAR power. If not possible, trip the machine immediately and inform to the maintenance staff for thorough checking of the Automatic Voltage Regulator (AVR) and its associated parts.
Relays acted : a. Flag operation at Protection panel.
b. Acting of Master relay
c. Indication at Annunciation Panel.
Consequences : a. Tripping of 220KV breaker
b. Tripping of Field breaker
c. Stop command to Turbine thro’ Mark-IV
Status : a. Unit is at coasting down.

4.NEGATIVE SEQUENCE OR CURRENT UNBALANCE PROTECTION :
Setting : Alarm – 75% of 12s Time - 5 Sec.
Trip – 75% of 12s Time - 300 Sec.
When the machine delivering the equal currents in three phases, no unbalance or negative phase sequence current is produced as the vector sum of these currents is zero, when the generator is supplying an unbalanced load to a system, a negative phase sequence current is imposed on the generator. The system unbalance may be due to opening of lines, breaker failures or system faults. The negative sequence current in the stator winding creates a magnetic flux wave in the air gap which rotates in opposite direction to that of rotor synchronous speed. This flux induces currents in the rotor body, wedges, retaining rings at twice the line frequency. Heating occurs in these areas and the resulting temperatures depend upon the level and duration of the unbalanced currents. Under these conditions it is possible to reach temperatures at which the rotor material no longer contain the centrifugal forces imposed on them resulting in serious damage to the turbine-generator set. Any machine as per design data will permit some level of negative sequence currents for continuous period.
An alarm will annunciate at annunciation panel if negative sequence currents exceeds a normal level. Reduce the MVAR power on the machine if necessary load also and keep the machine for some time till the alarm vanishes at annunciation panel. If the machine trips on the Negative sequence protection never take the machine into service until the temperatures on the rotor parts settle down to its lower value. Resynchronize the machine to the grid after considerable time under grid & feeder parameters are within limits. If the unit trips again on the same protection, stop the machine after consideration time so as to cool down the rotor parts and inform to the maintenance staff for thorough examination of the system.
Relays acted : a. Flag operation at Protection panel.
b. Acting of Master relay
c. Indication at Annunciation Panel.
Consequences : a. Tripping of 220KV breaker
b. Tripping of Field breaker
Status : a. Unit is at FSNL.

5. OVER FLUXING OR EXCITATION OR VOLTS PER HERTZ PROTECTION:
Setting : Alarm – 1.17 Time - 10 Sec.
Trip – 1.17 Time - 30 Sec.
Per unit voltage divided by per unit frequency commonly called Volts/Hertz is a measurable quantity that is proportional to flux in the generator or step-up transformer cores. Moderate over fluxing (105-110%) increases core loss resulting in increase of core temperatures due to hysterics & eddy currents loss. Long term operation at elevated temperatures can shorten the life of the stator insulation. Severe over fluxing can breakdown inter-laminar insulation followed by rapid local core melting. Over fluxing normally can be caused by over speed of the turbine or over excitation during Off-line condition, and load rejection or AVR mal-functioning during On-line condition.
If alarm annunciation panel, Increase/Reduce the speed of the turbine to rated generator speed (3000RPM) and reduce the generator voltage to rated during Off-line condition. Reduce the MVAR power on the generator during On-line condition. If the machine trips on over fluxing protection during On-line, Keep the machine at FSNL till the grid parameters stabilize and resins. Again the machine trips on the same stop the machine for examination of the AVR & Governor systems by maintenance staff.
Relays acted : a. Flag operation at Protection panel.
b. Acting of Master relay
c. Indication at Annunciation Panel.
Consequences : a. Tripping of 220KV breaker
b. Tripping of Field breaker
c. Stop command to Turbine thro’ Mark-IV
Status : a. Unit is at coasting down.

6.OVER CURRENT WITH VOLTAGE RESTRAINT PROTECTION :
Setting : Alarm – 85% Time - 10 Sec.
Trip – 100% Time - 0.5 Sec.
Normally generators are designed to operate continuously at rated MVA, frequency and power factor over a range of 95 to 105% rated voltage. Operating the generator at rated MVA with 95% voltage, 105% stator current is permissible. Operating of the generator beyond rated KVA may result in harmful stator over current. A consequence of over current in winding is stator core over heating and leads to failure of insulation.
If alarm annunciates at annunciation panel, Reduce the stator current to the below the rated by reducing the MVAR power on the machine. When the trips on the same protection, Resins the machine after keeping the machine at FSNL for some time, and keep the stator current below the rated.
Relays acted : a. Flag operation at Protection panel.
b. Acting of Master relay
c. Indication at Annunciation Panel.
Consequences : a. Tripping of 220KV breaker
b. Tripping of Field breaker
Status : a. Unit is at FSNL.

7 STATOR EARTH FAULT PROTECTION :
Setting : 70% Time - 5 Sec.
Normally the generator stator neutral operates at a potential close to ground. If a faulty phase winding connected to ground, the normal low neutral voltage could rise as high as line-to-neutral voltage depending on the fault location. Although a single ground fault will not necessarily cause immediate damage, the presence of one increases the probability of a second. A second fault even if detected by differential relay, may cause serious damage. The usual method of detection fault is by measuring the voltage across the secondary of neutral grounding transformer (NGT). Here are two over lapping zones to detect stator ground faults in a high impedance grounded generator system, the two zones are put together cover 100% stator winding for earth faults. A fundamental frequency neutral over voltage relay covers about 0-95% of the stator zonal winding for all faults except those near the neutral. Another third harmonic neutral under voltage relay covers remaining 96-100% of the stator zone 2 winding on neutral side.
Relays acted : a. Flag operation at Protection panel.
b. Acting of Master relay
c. Indication at Annunciation Panel.
Consequences : a. Tripping of 220KV breaker
b. Tripping of Field breaker
c. Stop command to Turbine thro’ Mark-IV
Status : a. Unit is at coasting down.

8.ROTOR EARTH FAULT PROTECTION (64R) :
Settings : Less than 80K ohm
Any rotor field winding of the generator is electrically isolated from the ground. Therefore the existence of one ground fault in the field winding will usually not damage the rotor. However the presence of two or more ground faults in the winding will cause magnetic and thermal imbalance plus localized heating and damage to the rotor metallic parts. The rotor earth fault may be caused due to insulation failure of winding or inter-turn fault followed by localized heat.
Relays acted : a. Flag operation at Protection panel.
b. Acting of Master relay
c. Indication at Annunciation Panel.
Consequences : a. Tripping of 220KV breaker
b. Tripping of Field breaker
c. Stop command to Turbine thro’ Mark-IV
Status : a. Unit is at coasting down.

9.RESTRICTED EARTH FAULT PROTECTION:
Settings : 0.1 Amp. Time : Instantaneous
It is similar to generator differential protection in working. It protects the high voltage winding of 11/220KV power transformer against internal faults. One set current transformers of the power transformer on neutral and phase side, is exclusively used for this protection. The protection can not detect turn-to-turn fault within one winding. Upon the detection of a phase-to-phase or phase-to-ground fault in the winding, the unit to be tripped without time delay.
Relays acted : a. Flag operation at Protection panel.
b. Acting of Master relay
c. Indication at Annunciation Panel.
Consequences : a. Tripping of 220KV breaker
b. Tripping of Field breaker
c. Stop command to Turbine thro’ Mark-IV
Status : a. Unit is at coasting down.
Once the restricted earth fault protection operated, the unit can not be taken into service unless the transformer winding is thoroughly examined by the maintenance staff for any internals faults. 

10.BACKUP IMPEDANCE PROTECTION:
Settings ; K1-3, K2-0.71 Time – 1.5 Sec.
As in name implies, it is used to protect the generator from supplying the over loaded or faulty system. It is backup protection of the generator over current protection. In measures ratio of the voltage and current supplied by the generator and initiates trip signal when the measured impedance is less than the preset value.
If the machine trips on the Backup protection, never take the machine into service until the temperatures of the generator settle down to its lower value. Resynchronize the machine to the grid after considerable time when grid & feeder parameters are within limits.
Relays acted : a. Flag operation at Protection panel.
b. Acting of Master relay
c. Indication at Annunciation Panel.
Consequences : a. Tripping of 220KV breaker
b. Tripping of Field breaker
c. Stop command to Turbine thro’ Mark-IV
Status : a. Unit is at coasting down.

11.LOW FORWARD POWER PROTECTION:
Setting : 0.5% Time : 1 Sec.
The generator will not develop output power when turbine input is less than the no load losses and motoring action develops on the turbine. The generator is able to generate power, usually 55 to 10% of generator capacity, within pre-determined time after closing of 220KV breaker.
Relays acted : a. Flag operation at Protection panel.
b. Acting of Master relay
c. Indication at Annunciation Panel.
Consequences : a. Tripping of 220KV breaker
Status : a. Unit is at FSNL with potential.
The unit trips on the low forward protection, Resins the machine and increase input power to the turbine as quickly as possible within low forward power time setting. Even after two to three attempts, the machine is tripping on the same protection; probably the governor of turbine is faulty. Inform to maintenance staff for rectification of the same.

12.REVERSE POWER PROTECTION:
Setting : 0.5% Time - 2.0 Sec.
It is backup protection to the low forward protection. Motoring of a generator will occur when turbine output is reduced such that it develops less than no-load losses while the generator is still on-line, the generator will operate as a synchronous motor and driving the turbine. The generator will not be harmed by synchronous motoring and a steam turbine can be harmed through over heating during synchronous motoring if continued long enough. The motoring of the turbine output can be detected by reverse power protection. The avoid false tripping due to power swings a time delay is incorporated before tripping signal is generated.
Relays acted : a. Flag operation at Protection panel.
b. Acting of Master relay
c. Indication at Annunciation Panel.
Consequences : a. Tripping of 220KV breaker
b. Tripping of Field breaker
c. Stop command to Turbine thro’ Mark-IV
Status : a. Unit is at coasting down.
The unit trips on the reverse power protection. Resins the machine and increase the input power to the turbine as quickly as possible within low forward power time setting. Even after two to three attempts, the machine is tripping on the same protection; probably the governor of turbine is faulty. Inform to maintenance staff for rectification of the same.

13.POLE SLIP OR OUT-OF-STEP PROTECTION:
Setting : 6.9 ohm.
When a generator loses synchronism, the resulting high current peaks and off-frequency operation may cause winding stresses, pulsation torques and mechanical resonances that have the potential danger to turbine generator. Therefore, to minimize the possibility of damage, it is generally accepted that the machine should be tripped without time delay preferably during the first half-slip cycle of the loss of synchronism condition. The electrical center during loss-of-synchronous conditions can occur in the generator as a result of increased impedance of the generator while decrease system impedance. The protections normally applied in the generator zone such as back-up impedance, loss of excitation etc., will not protect a generator during loss of synchronism under normal generator conditions.
Relays acted : a. Flag operation at Protection panel.
b. Acting of Master relay
c. Indication at Annunciation Panel.
Consequences : a. Tripping of 220KV breaker
b. Tripping of Field breaker
c. Stop command to Turbine thro’ Mark-IV
Status : a. Unit is at coasting down.
The unit trips on the Pole slip protection, Resynch the machine after stabilization of the grid parameters

14.POLE DISCREPANCY PROTECITON:
Setting : 0.5 Sec.
If One or two poles of generator breaker fail to close during synchronization, all poles of the breaker trip on this protection. It may be due to mechanical failure of the breaker un equal distribution of closing signal to the breaker from protection system.
Relays acted : a. Flag operation at 220KV Breaker panel.
b. Indication at Annunciation Panel.
Consequences : a. tripping of 220KV breaker
Status : a. Unit is at FSNL with potential.
The generator breaker trips on the pole discrepancy protection, Resynch the generator. Even after two to three attempts, the machine is tripping on the same protection, probably the generator breaker is faulty. Inform to maintenance staff for rectification of the same.

15.LOCAL BREAKER BACKUP PROTECTION:
Setting : 25% Time : 0.8 Sec.
For most of the faults, the generator breaker involves tripping the generator from the system. Failure of the breaker to open probably results in loss of protection and other problems such as motoring action or single phasing, If one or two poles of the generator breaker fail to open due to mechanical failure in breaker mechanism, the result can be a single phasing and negative phase sequence currents inducted on the rotor. The LBB protection is energized when the breaker trip is initiated after a suitable time interval if confirmation of the confirmation of breaker tripping from three poles is not received. The energized tripping signal from LBB protection will trip all 220KV generator breakers and all 220KV feeder breakers through Bus-bar protection.
Relays acted : a. Flag operation at Protection panel.
b. Acting of Master relay for all units.
c. Indication at Annunciation Panel.
Consequences : a. Tripping of 220KV breaker
b. Tripping of Field breaker of all units.
Status : a. all Units are at FSNL.
Once the LBB protection operated, the entire station is in dark. First restore all essential services to all units such as lube oil system and turning gear etc., from battery backup and. Checkup the faulty 220KV breaker and isolate the breaker from the system by opening the both side of the isolators.
After restoring all services from station supply, Close 220KV feeder breakers first and take all units into service one after the other duly co-coordinating with the DE/LD.
Since it involves complex operation, it is necessary to get help from maintenance staff for restoring the normally in the station. Never attempt to close the faulty 220KV generator in panic as it causes permanent damage to the generator and transformer.

16.BUS BAR PROTECTION:

Setting : 0.8 Amp.
There are mainly three protection zones namely called generator zone, bus duct transformer zone, 220KV breakers zone. The protection of generator zone and bus duct & transformer zone are covered in previous schemes. All 220KV breakers at switchyard will come under Bus-Bar protection. Functioning of this scheme is similar to the generator differential protection or generator-transformer differential protection. It measures all incoming currents from the generators at 220KV side and all outgoing currents in 220KV feeders, and initiates trip signal if it detects any deviation more than the preset value as the algebraic sum of all currents at 220KV bus must be less than the preset value. It isolates all 220KV generator breakers and all 220KV feeder breakers connected to 220KV bus.
Relays acted : a. Flag operation at Protection panel.
b. Acting of Master relay for all units.
c. Indication at Annunciation Panel.
Consequences : a. Tripping of 220KV breaker
b. Tripping of Field breaker of all units.
Status : a. all Units are at FSNL.
Once the Bus-Bar protection operated, the entire station is in dark. First restore all essential services to all units such as lube oil system and turning gear etc., from battery backup and 6.6/0.44KV Stage – II reserve power supply. Checkup the entire 220KV switch yard for any wire snapping or equipment damage.
After restoring all services from station supply, Close 220KV feeder breakers first and take all units into service one after the other duly co-ordinating with the DE/LD.
Since it involves complex operation, it is necessary to get help from maintenance staff for restoring the normalcy in the station. Never attempt to restore the 220KV supply at switch yard in panic unless the entire system is thoroughly examined and satisfy yourself as it causes permanent damage to the equipment or injury/death to the person working at switch yard.

17.OVER FREQUENCY PROTECTION:
Setting : 52 Hz Time - 2 Sec.
For a generator connected to a system, abnormal frequency operation is a result of a severe system disturbance. The generator can tolerate moderate over frequency operation provided voltage is within an acceptable limits. The machine operated at higher speeds at which the rotor material no longer contain the centrifugal forces imposed on them resulting in serious damage to the turbine-generator set. The abnormal over frequency on the machine may be due to improper speed control adjustment or disoperation of the speed controller or severe grid disturbance or sudden load through off.
Relays acted : a. Flag operation at Protection panel.
b. Acting of Master relay
c. Indication at Annunciation Panel.
Consequences : a. Tripping of 220KV breaker
b. Tripping of Field breaker

c. Stop command to Turbine thro’ Mark-IV
Status : a. Unit is at coasting down.
The unit trips on the over frequency protection, Resins the machine. Even after two to three attempts, the machine is tripping on the same protection; probably the governor of turbine is faulty. Inform to maintenance staff for rectification of the same.

18.UNDER FREQUENCY PROTECTION:

Setting : 48 Hz Time : 2.0 Sec.
For a generator connected to a system, under frequency operation is a result of a severe system disturbance. The generator can tolerate moderate under frequency operation provided voltage is within an acceptable limits. The machine operated at lower higher speeds causes severe over fluxing in the generator-transformer. The abnormal under frequency on the machine may be due to improper speed control adjustment or disoperation of the speed controller.
Relays acted : a. Flag operation at Protection panel.
b. Indication at Annunciation Panel
Consequences : a. NIL
Status : a. Unit is at lower speed with potential.
Increase governor speed until machine reaches full speed. Even after two to three attempts, the machine are running at lower speed, probably the governor of turbine is faulty. Inform to maintenance staff for rectification of the same. 

19.OVER VOLTAGE PROTECTION :

Setting : a. 110% Time - 2.0 Sec.
b. 120% Time - 0.3 Sec.
Generator voltage is at present value under normal operating conditions as selected by operator in AVR. If it parts from preset value, May be due to AVR mal-functioning or a system disturbance. Severe over voltage can cause over fluxing and winding insulation failure. The over voltage protection can be considered as a backup to the Volts-per-Hertz protection.
Relays acted : a. Flag operation at Protection panel.
b. Acting of Master relay
c. Indication at Annunciation Panel.
Consequences : a. Tripping of 220KV breaker
b. Tripping of Field breaker
Status : a. Unit is at FSNL without potential.
Raise the generator voltage slowly with manual mode in AVR and keep generator voltage within the limits of normal voltage. If it is unable to control the generator voltage, trip the field breaker and inform to the maintenance staff for rectification of the AVR.

High Voltage Pulse Generators


Many applications require a repetitive source of high voltage pulses having fast rise and fall times. These applications include drivers for piezo-electric devices, ion tubes, gas tubes, liquid polarizing cells, beam steering applications, the generation of electric fields in aqueous solutions, and time-of-flight mass spectrometry measurements.
A high voltage pulse generator consists, essentially, of a high voltage power supply and a high voltage switch capable of alternately connecting and disconnecting this voltage source to a load. A simplified pulse generator is shown below. Here the high voltage supply charges a reservoir capacitor while the high voltage switch (HVS) is open. When HVS is closed, this reservoir capacitor rapidly supplies a pulse of current to charge the various capacitances (consisting of internal, cable, and load capacitances, as shown) to the full pulse amplitude and then, with the help of the power supply, supplies a steady current as determined by the load resistance to maintain this amplitude until HVS is again opened.
High Voltage Pulse Generators  in a Circuit
Although a high voltage pulse is the desired waveform, it is important to consider the current waveform required to produce this voltage pulse because it is this current waveform that sets important requirements on both the power supply and the high voltage switch. Current through the high voltage switch is a function of the sum of all internal, cable, and load capacitances and the load resistance. All three capacitances and the load resistance also have a significant impact on the rise and fall times of the pulse. A common problem with many users is in failing to consider these effects when specifying pulse operating requirements. Let’s consider a typical current waveform in more detail.
Component of Current Pulse
This current waveform consists of two parts: an initial sharp pulse and then a steady component. The sharp pulse of current, which determines the voltage pulse 10% to 90% rise time, has an average value as given by the following equation, where dV is the change in pulse amplitude during the rise time and dT is the rise time. As a rule of thumb, the peak current during the rise time is 2 to 3 times this average value.
Iaverage-rise = [Cinternal + Ccable + Cload] dV/dT
The surrent required to maintain the pulse amplitude across the load resistor is as follows, where R is the value of the load.
Iflat top = Pulse Amplitude / R
The 90% to 10% pulse fall time is given by the following equation:
Fall Time = 2.2 R [Cinternal + Ccable + Cload]
Consider this typical application. A 3.2 kV pulse generator with a 1 ns rise time and 12 pF of internal stray capacitance is connected to a Pockels Cell having a capacitance of 1 pF and a resistance of 10 M ohms via a 2-foot length of RG 114, 185 ohm coaxial cable. This cable has a capacitance of 6.5pF per foot when not terminated in its characteristic impedance. The values give:
Iaverage-rise = [12 pf +13 pf +1 pf] [3,200 volts / 1 ns] = 83.2 amps

Ipeak-rise ~ 160 amps

Iflat top = [3,200 volts / 10 M ohms] = 320 µa

Fall Time = 2.2[10 M ohms] [12 pf + 13 pf + 1 pf] = 572 µs
Therefore, to drive a 1 pF Pockels Cell, through 2 feet of 185 ohm cable, from 0 to 3.2 kV in 1 ns requires a peak current of approximately 160 A. The fall time is slow because the various capacitors are discharged through the 10 M ohms resistor when the high voltage switch is opened. The fall time may be made faster by using a shunt resistor across the cell terminals.
As an example, consider what happens when the cable is terminated in its characteristic impedance by adding a 185 ohm shunt resistor across the load. This reduces the current required during the pulse rise time dT by effectively eliminating the cable capacitance, increases the current required from the power suppluy to maintain the pulse amplitude, and reduces the pulse fall time.

Iaverage-rise = [12 pf +1 pf] [3,200 volts / 1 ns] = 41.6 amps

Ipeak-rise ~ 80 amps

Iflat top = [3,200 volts / 185 ohms] = 17 amps

Fall Time = 2.2[185 ohms] [12 pf + 1 pf] = 5.3 ns
Another technique that can be used to reduce the pulse fall time and minimize the effects of load and cable capacitance is to add another high voltage switch from the load to ground. When the first HVS is turned off this HVS is turned on, effectively discharging the load capacitance to ground, or “biting the tail” of the pulse. This generally results in a fall time that is less dependent on the load capacitance and resistance. The average pulse current is also decreased since a shunt resistor across the load is no longer required. The addition of the second switch increases the cost of the pulse generator and, in most cases, has a minimal effect on the rise time.
The HV Pulse 5k-2500 is an example of a pulse generator that utilizes a tail biter to control pulse fall time. This pulser is designed to drive the grid of a high power vacuum tube, which presents a large load capacitance. Assume a pulse amplitude 0-5 kV and a load that looks like 250 ohms in parallel with a total of 1450 pF. The design goal is to keep the pulse fall time below 200 ns. With no tail biter, the approximate fall time would be:
Fall Time = 2.2[250 ohms] [100 pf + 1450 pf] = 853 ns
When a tail biter consisting of a current-limiting resistor of 70 ohms in series with a second HVS is introduced across the load, the fall time is reduced to:
Fall Time = 2.2[250 ohms || 70 ohms] [100 pf + 1450 pf] = 187 ns
It is apparent that load capacitance, including cable capacitance, is a very important consideration in the design and application of high voltage pulsers. Depending on operating requirements, the effects of capacitance can be controlled in several ways: the length of the interconnecting cable can be made as short as possible, a shunt resistor can be added across the load, or a tail biter can be introduced into the circuit.

10 good reasons why to study Electrical Engineering


1. It's easy to get your first job

Electrical engineering students fairly easy find their first job because most employers in electrical field search for fresh mind, with fresh knowledge and at the same time they get young people they can mold to their own specific needs and make experts out of them.

2. You can work in another country

Working as electrical engineer opens you lots of opportunities in other countries. Laws of math, electricity and physics are universal and your gained knowledge doesn't limit you to only the country you studied in. There are a lot of international companies that need electrical engineers, also most of them are willing to employ people form other countries, and most of them operate on international level that offers you additional options of traveling while working. Besides, you are usually getting payed well for it!

3. Student praxis can be extended to employment

Most European universities demand students of electrical engineering to get short praxis with companies before they graduate and usually, if you perform well you can extend your praxis into employment after graduation. The employer already knows you already, they know your skills and work ethics and also they usually start to mold you in their "specific needs" profile during your praxis.

4. You gain a wide range of knowledge during your studies

Thinking that electrical engineering is just one dimensional is wrong. The range of knowledge gained during studies is amazingly broad and versatile. Even just basic studies gives you wide range of skills - from programming to writing reports; lets face it, reports are required on every step of electrical engineering studies and every employer will demand writing reports on different fields you work on. Even though you are studying a specific part of electrical engineering you will get basics of almost all aspects of electrical engineering and it shouldn't be a big problem to find solutions to a problem that is not strictly in your specific field of expertise.


5. Computer skills

Modern world is run by computers. Most of the people use it on regular basis, but some still struggle with some operations that demand knowledge, that goes just a little bit beyond "Click an icon". Electrical engineers are faced with computer problems on every step of their studies and also every day on a job, that's why we usually gain computer skills during studies, when we have to install different programs for our studies, run analysis and tweak components or electrical circuits. Computers become parts of us and we know that hitting them won't make them run faster but fixing might...

6. Adrenaline

Maybe adrenaline isn't first thing that pops in your mind when you think about electrical engineering, but trust me there will be a lot of adrenaline rush moments if you get in electrical engineering. Occasional jolts of electrical charge that hits you when you aren't paying attention and touch the leads of charged capacitor or when you connect 2 wires that you shouldn't or an electrical component more or less explodes in front of your eyes because you connected it on the testing board in the wrong way... Those events make you jump out of your chair and definitely raise your adrenaline level. On the other hand you won't most likely do the same mistake again!

7. DIY

DIY or "Do It Yourself" is one of more exciting reasons why to get in electrical engineering. When you know how stuff works, what usually malfunction and what are basic rules of electrical engineering you can make your own stuff that usually you need to search for and buy. It's not always cheaper, although some solutions will save you great deal of money, but it works as you want it to work and it's your own creation what gives it additional value and also nice reference in your CV if you are applying for a job. 

8. Mr./Mrs. Fix-It

Not only everyday fixes, like changing a burned out light bulb or faulty fuse aren't scary moments any more - you might also be able to cope with more complex problems with your computer etc. That doesn't only save you money but also works great as a pick up line...

9. New stuff gets out all the time - it never gets boring

Electrical and electronic components are modified, invented and reinvented every day, so you will never be bored because you are using same process or component for the last 10 years. New and exciting stuff is available all the time and you will have lots of fun testing an assembling it.

10. Only few simple rules to follow

    Things work better when plugged to power
    Electrical components work on smoke - when it gets out you are in trouble
    If things don't work, read a manual.

List of electrical engineers


This is a list of electrical engineers, people who made contributions to electrical engineering or computer engineering.
Who Contribution(s)
Norman Abramson ALOHAnet network communication
Edwin Armstrong Regenerative circuit, frequency modulation (FM)
William Edward Ayrton Measuring instruments, electric railways, searchlight
John Bardeen Two Nobel prizes: transistor, superconductivity
Emile Baudot Telegraphy communications
Andy Bechtolsheim Cofounder of Sun Microsystems
Arnold Orville Beckman pH meter, Beckman Instruments, Silicon valley pioneer
Alexander Graham Bell Bell telephone company
Alfred Rosling Bennett Pioneer of electric lighting and telephones
Harold Stephen Black Negative feedback amplifier
Ottó Bláthy Pioneering electrical engineer
André Blondel Oscillography, electrical machine theory
Alan Blumlein Inventions in telecommunications, sound recording, stereo, television, radar
Hendrik Wade Bode Control theory, Bode plot
Paul Boucherot Reactive power
Karlheinz Brandenburg Audio compression scheme MP3
Charles Tilston Bright Transatlantic cable
Charles Eugene Lancelot Brown co-founder of Brown, Boveri & Cie
William C. Brown crossed-field amplifier, microwave power transmission
Walter Bruch Television pioneer, inventor of the PAL colour television system
Charles F. Brush Efficient dynamos, electric lighting,founder of one of the General Electric companies, wind power
Charles Frederick Burgess Batteries' development, pioneer of electrochemical engineering
Alan Archibald Campbell-Swinton Theory of television
Marvin Camras Magnetic recording
John Renshaw Carson Single-sideband modulation
James Kilton Clapp Clapp oscillator, General Radio Corporation
Lynn Conway very large scale integrated circuit design, Mead & Conway revolution
William Coolidge X-rays
William Corin Snowy Mountains Scheme
R. E. B. Crompton electric lighting, instruments, manufacturer
Seymour Cray Supercomputer architect
Sidney Darlington the Darlington transistor
Lee DeForest Audion vacuum tube
Georges de Mestral Velcro
Jack Dennis time sharing, Multics
Robert H. Dennard Dynamic random access memory
Marcel Deprez HVDC power transmission pioneer
Bern Dibner Founder Burndy Co., electrical connectors, historian of the Transatlantic cable
Mikhail Dolivo-Dobrovolsky Inventor of three-phase motor
Ray Dolby Dolby sound
William Duddell Oscillography, the singing Arc lamp
Allen B. DuMont television manufacturing pioneer
J. Presper Eckert Computer pioneer
Thomas Edison Prolific inventor: phonograph, first practical light bulb, telegraph improvements
Douglas Engelbart computer mouse, hypertext
Justus B. Entz Electric transmission,electric vehicles, worked with Edison
A. K. Erlang Communications and Queueing
Lloyd Espenschied Developments in radio communications and coaxial cable technology.
Federico Faggin Intel microprocessor, Zilog z80
Michael Faraday Discovered electromagnetic induction and Faraday shield
Moses G. Farmer Electric railway
Philo T. Farnsworth American television pioneer
Galileo Ferraris Rotating magnetic field
Sebastian Ziani de Ferranti Ferranti Corporation
Reginald Fessenden "Father of Radio Broadcasting"
Donald G. Fink Radio navigation LORAN, television standards, author
Gerhard Fischer Handheld metal detector
John Ambrose Fleming Inventor of the thermionic valve (vacuum tube)
Thomas Flowers Designer of the first programmable digital electronic computer
Jay Forrester American computer pioneer
Charles Legeyt Fortescue symmetrical components for three-phase power system analysis
Jean Baptiste Joseph Fourier Physicist; Fourier transform / Fourier series
Leonard F. Fuller radio pioneer, carrier current on power systems
Dennis Gabor Hungarian inventor of holography, Nobel Laureate
Zénobe Gramme Dynamo
Elisha Gray telephone pioneer
Richard Grimsdale transistorized computers
Edward E. Hammer Spiral Compact fluorescent lamp
Ralph Hartley Electronics
Oliver Heaviside Re-formulated Maxwell's equations (vector calculus)
Oskar Heil field-effect transistor, loudspeaker
Heinrich Rudolf Hertz Hertzian Waves
Peter Cooper Hewitt Mercury vapor lamp, mercury arc rectifier
William Hewlett Hewlett-Packard
Hugo Hirst Co founder, General Electric Company plc
Godfrey Hounsfield Inventor of the world's first computed tomography (CT) scanner, shared a 1979 Nobel prize
Edwin J. Houston Arc lighting, cofounder of what would become General Electric, president of AIEE
John Hopkinson Inventor of Three-phase electrical system
Grace Hopper Computer programmer (first compiler)
Paul Horowitz SETI, coauthor of The Art of Electronics
Lawrence A. Hyland Radar pioneer, leader of Hughes Aircraft
Kees Schouhamer Immink Pioneer optical recording, CD, DVD, Blu-ray Disc
Samuel Insull Central station generation, electrical utilities, Edison Pioneer
Fleeming Jenkin Submarine telegraph cables
Bill Joy Unix - Sun Microsystems
Rudolf Kalman Inventor of the Kalman filter
Kálmán Kandó Pioneer of high voltage railway electrification systems
Nathaniel S. Keith founding secretary AIEE; electric power
Arthur E. Kennelly complex numbers in AC circuit theory
Charles Kettering Automobile electrical innovations, Delco founder
Jack Kilby Nobel prize: Integrated circuit
Max Knoll Electron microscope
John D. Kraus Radio telescope, antennas
Herbert Kroemer Heterostructures and semiconductor physics
Eric Laithwaite Linear induction motor
Hedy Lamarr Communications
Uno Lamm Swedish, HVDC and mercury arc valves
Benjamin G. Lamme Niagara Falls power engineering
Georges Leclanché primary battery
Morris E. Leeds Leeds & Northrup measurement and control devices
Alexander Lodygin Russian, incandescent lighting, motors
Östen Mäkitalo Father of Cellular Phone
Guglielmo Marconi Practical radio
Orlando R. Marsh electrical sound recording
Erwin Otto Marx Marx generator high voltage DC
John Mauchly ENIAC designer
Charles Hesterman Merz NESCO Electric power grid, England
William Henry Merrill founder of Underwriters Laboratories
Robert Metcalfe Ethernet, 3Com
John L. Moll Solid-state physics, the Ebers-Moll transistor model
Robert Moog Electronic music pioneer, invented Moog synthesizer
Daniel McFarlan Moore electrical discharge lighting
Shuji Nakamura blue gallium-nitride Light emitting diodes
Edward Lawry Norton Norton's theorem
Robert Noyce Co-founder of Fairchild Semiconductor and Intel
Bernard M. (Barney) Oliver Hewlett-Packard, Founder HP Labs
Kenneth Olsen Magnetic core memory; Digital Equipment Corporation
Stanford R. Ovshinsky semiconductors
David Packard Hewlett-Packard
Robert H. Park Park's transformation
Donald Pederson Father of SPICE
G. W. Pierce oscillator, crystal control
William Henry Preece Telegraphy, nemesis of Heaviside
Franklin Leonard Pope telegraphy, electric lighting, Edison influence
Valdemar Poulsen Magnetic recording
Michael I. Pupin Long-distance telephone communication. "Pupin coil"
Simon Ramo Physicist, microwaves, missiles, founder TRW and Bunker Ramo Corporation
Richard H. Ranger wireless fax, radar, magnetic tape recording
Alec Reeves Inventor of pulse code modulation
Johann Philipp Reis Inventor of the Reis telephone
Hyman G. Rickover "Father of the Nuclear Navy"
Edward S. Rogers, Sr. Inventor of the first successful AC radio tube
Harold Rosen Syncom communication satellite
H. J. Round Radio pioneer and assistant to Guglielmo Marconi
Reinhold Rudenberg Electron microscope
Carl Louis Schwendler Electric lighting and telegraph
Thomas Johann Seebeck Thermoelectric effect
Oliver B. Shallenberger AC electricity meters
Claude Shannon "Father of Communication Theory"
Ernst Werner von Siemens Inventor, industrialist, Siemens & Halske, Siemens (unit)
Carl Wilhelm Siemens Telegraphy, motors and generators, electric pyrometer
Alexander Siemens Electric lighting, power, Society of Telegraph Engineers (predecessor to IEE)
Phillip Hagar Smith Smith chart
Percy Spencer Microwave oven
Frank J. Sprague "Father of Electric Traction"
Chauncey Starr Founder, Electric Power Research Institute
Charles Proteus Steinmetz Alternating current theories
Sarkes Tarzian Radio inventor, broadcasting, radio manufacturer
Albert H. Taylor First demonstration of radar
Bernard D. H. Tellegen inventor of the Pentode, formulated Tellegen's theorem
Nikola Tesla Revolving magnetic field electric motor, Tesla coil, Polyphase transmission systems, transformer
Silvanus P. Thompson Educator, author, electrical machinery, X-rays, radio
Elihu Thomson Entrepreneur, co-founder of what would become General Electric
William Thomson (Lord Kelvin) Telegraphic cables
René Thury High voltage direct current power transmission, electric traction
Kálmán Tihanyi Television pioneer
Charles Joseph Van Depoele Electric railway pioneer
C. F. Varley Submarine cable, Varley bridge
Milan Vidmar Power transformers and transmission of electric current
Andrew Viterbi Communications
Trevor Wadley Innovations in radio and microwave technology
Harry Ward Leonard Inventor of the Ward Leonard control system.
Robert Watson-Watt First practical radar
George Westinghouse AC power industrialist
Harold Alden Wheeler Automatic volume control, radar
Uncas A. Whitaker Founder of AMP Inc. and philanthropist
Bob Widlar Integrated circuits
Niklaus Wirth Computer programming languages
Steve Wozniak Personal computers; Apple Computer
Pavel Yablochkov Electric arc lighting
Jerry Yang Co-Founder, Former CEO of Yahoo
Hidetsugu Yagi Yagi-Uda antenna
Otto Julius Zobel Filters
Konrad Zuse Computers

Introduction to installing power cables


1. Open-Wire
Open-wire construction consists of uninsulated conductors on insulators which are mounted on poles or structures. The conductor may be bare or it may have a thin covering for protection from corrosion or abrasion. The attractive features of this method are its low initial cost and the fact that damage can be detected and repaired quickly.

On the other hand, the uninsulated conductors are a safety hazard and are also highly susceptible to mechanical damage and electrical outages resulting from short circuits caused by birds or animals. Proper vertical clearances over roadways, walkways, and structures are critical. Exposed open-wire circuits are also more susceptible to the effects of lightning than other circuits, however, these effects may be minimized by the use of overhead ground wires and lightning arresters.

In addition, there is an increased hazard where crane or boom truck use may be involved. In some areas contamination on insulators and conductor corrosion can result in high maintenance costs.

2. Aerial Cable

Aerial cable consists of fully insulated conductors suspended above the ground. This type of installation is used increasingly, generally for replacing open wiring, where it provides greater safety and reliability and requires less space.

Properly protected cables are not a safety hazard and are not easily damaged by casual contact.



They do, however, have the same disadvantage as open-wire construction, requiring proper vertical clearances over roadways, walkways, and structures.

2.1 Supports

Aerial cables may be either self-supporting or messenger-supported. They may be attached to pole lines or structures. Self-supporting aerial cables have high tensile strength for this application. Cables may be messenger-supported either by spirally wrapping a steel band around the cables and the messenger or by pulling the cable through rings suspended from the messenger.

2.2 Distance

Self-supporting cable is suitable for only relatively short distances, with spans in the range of 100-150 feet. Messenger-supported cable can span relatively large distances, of over 1000 feet, depending on the weight of the cable and the tensile strength of the messenger. For this reason, aerial cable that must span relatively large distances usually consists of aluminum conductors to reduce the weight of the cable assembly.

The supporting messenger provides high strength to withstand climatic rigors or mechanical shock. It may also serve as the grounding conductor of the power circuit.

3. Above-Ground Conduits

Rigid steel conduit systems afford the highest degree of mechanical protection available in above-ground conduit systems. Unfortunately, this is also a relatively high-cost system. For this reason their use is being superseded, where possible, by other types of conduit and wiring systems.

Where applicable, rigid aluminum, intermediate-grade steel conduit, thin-wall EMT, intermediate-grade metal conduit, plastic, fiber and asbestos-cement ducts are being used.

4. Underground Ducts

Underground ducts are used where it is necessary to provide a high degree of safety and mechanical protection, or where above-ground conductors would be unattractive.

4.1 Construction
Underground ducts use rigid steel, plastic, fiber, and asbestos-cement conduits encased in concrete, or precast multi-hole concrete with close fitting joints.
Clay tile is also used to some extent. Where the added mechanical protection of concrete is not required, heavy wall versions of fiber and asbestos-cement and rigid steel and plastic conduits are direct buried.

4.2. Cables
Cables used in underground conduits must be suitable for use in wet areas, and protected against abrasion during installation.

5. Direct Burial

Cables may be buried directly in the ground where permitted by codes and only in areas that are rarely disturbed. The cables used must be suitable for this purpose, that is, resistant to moisture, crushing, soil contaminants, and insect and rodent damage. While direct-buried cable cannot be readily added to or maintained, the current carrying capacity is usually greater than that of cables in ducts. Buried cable must have selected backfill.

It must be used only where the chance of disturbance is unlikely. The cable must be suitably protected, however, if used where the chance of disturbance is more likely to occur.

Relatively recent advances in the design and operating characteristics of cable fault location equipment and subsequent repair methods and material have diminished the maintenance problem.


6. Underwater (Submarine) Cable

Submarine cable is used only when no other cable system can be used. It supplies circuits that must cross expanses of water or swampy terrain.

6.1 Construction

Submarine cable generally consists of a lead sheathed cable and is usually armored. Insulation material should be XLP or EPR, except when paper insulation is justified because of its high resistance to, and freedom from, internal discharge or corona.

Multiconductor construction should be used, unless limited by physical factors. The lead sheathing usually consists of a copper-bearing lead material, however, other alloys may be required when special conditions warrant nonstandard sheathing. The most common type of  armoring material used for submarine cables is the spirally wrapped round galvanized steel wire.





Standard applications for submarine power cables to connect mainland areas or cities via water passages. This applies to mainland-to-island connections. Many of these networks and connections are getting older and need to be overhauled. We are constantly working on the continuous refinement of these products to reduce environmental effects (precisely during the laying process) and losses during power transmission (using new materials).

In this type of cable, asphalt impregnated jute is usually applied over the lead sheath and the wire armor is applied over the jute to reduce mechanical damage and electrolytic corrosion. An additional covering of the asphalt impregnated jute may be applied over the wire armor.
Nonmetallic sheathed cables are sometimes suitable for certain submarine applications. The cable must be manufactured specifically for submarine service and, generally, has an increased insulation thickness. The cable may require wire armor and should have electrical shielding for all voltage ratings above 600 V.

6.1 Installation

Submarine cable should lie on the floor of the body of water and should have ample slack so that slight shifting caused by current or turbulence will not place excessive strain on the cable. Where the cable crossing is subject to flow or tidal currents, anchors are often used to prevent excessive drifting or shifting of the cable. In addition to laying cables directly on the bottom, burying cable in a trench using the jet water method should be considered.

Cables must be buried in waters where marine traffic is present. The depth of burial should be enough to prevent damage caused by dragging anchors, which may be in excess of 15 feet for large ships on sandy bottoms.

Warning signs located on shore at the ends of the submarine cable should be provided to prohibit anchoring in the immediate vicinity of the cable.




Electrical Engineering Seminar Topics


1. Energy Conservation by Soft Start 
2. Power System Contingencies 
3. Direct torque control of AC drives 
4. Servomotor Magnetic resonance imaging (MRI 
5. Mild Hybrid Electric Vehicle 
6. Non conventional source (biomass 
7. Geothermal Energy 
8. Reactive Power Consumption in Transmission Line 
9. Pace maker 
10. Computer Clothing 
11. Robotics and its application 
12. Synchronous voltage source 
13. Space Solar Power 
14. Laser and its application 
15. Surge Arrestor 
16. Liquid Electricity 
17. Field oriented control drives without shaft sensors 
18. Hydrogen Fuel cell 
19. Fast Breeder Reactor 
20. Stepper Motor 
21. Single phase neutral point clamped AC/shos converter with power factor corrector and active filter 
22. Nano Wire 
23. High-Temperature Nuclear Reactors for Space Applications 
24. Medical Imaging Techniques 
25. Homo Polar Generator 
26. Transducer 
27. Maglev Train 
28. Automatic solar tracker 
29. Surge Protection in Modern Devices 
30. Load Monitoring 
31. Ultra sonic motor 
32. Effect on generating units caused by loss of excitation 
33. Ultra capacitors 
34. Remote Monitoring and Thought inference 
35. PWM technique applied to induction motor 
36. Expert Technician System 
37. Plastic chips 
38. Missile Technology 
39. Interactive Voice Response System 
40. Permanent magnet D C Motor 
41. Solar hybrid pvt systems 
42. Neural Networks application in Induction motor 
43. Bridge capacitor bank in EHV system 
44. Energy Efficient Motor 
45. Advancements in inverter technology for industrial applications 
46. Gas Insulated Transformer 
47. Gyro bus 
48. Ultrasonic sound detection and its applications 
49. Solar Ponds 
50. Electrostatic Generator 
51. Power System Solvability 
52. Automation of temp rise test for L T Switch gear 
53. Micro Fuel Cells 
54. Power Factor Correction 
55. Evacuated Tube Solar Collector 
56. Energy Storage within a Hydrogen Transportation Fuel Infrastructure 
57. Electrical Energy Management & Audit 
58. E-nose 
59. Installation Maintenance and application of power transformer 
60. Secure User Authentication using Automated Biometrics 
61. Speed Detection Camera 
62. Direct Broadcast Satellite 
63. Production of & Protection against Surge 
64. Implementation of PLC 
65. Automatic Circuit Recloser 
66. Flywheel Energy Storage 
67. Satellite Radio 
68. Uninterrupted Power Supply 
69. Superconductivity 
70. 66kv Receiving Sub-Station 
71. Availability based tariff scheme 
72. Magnetic Resonance imaging 
73. Artificial Neural Network 
74. DC circuit breaker 
75. Arc Fault Circuit Interrupters 
76. HVDC Converter 
77. Load Shedding 
78. D C Arc Furnace 
79. DSP (Digital Signal process Based Motor Control System) 
80. Integrated Gate Commutated Thyristor 
81. Vector control Of Induction Motor 
82. Energy Saving Motor 
83. Prepaid Energy meter 
84. Smartcard 
85. Power line carrier communication 
86. Multiterminal D C supply (MTDC 
87. Flexible Photovoltaic Technology 
88. Geothermal Power Stations 
89. Coal IGCC power production 
90. Wire less power transmission 
91. Condition Based Maintenance of UG Cable Systems 
92. Flexible AC transmission System 
93. Wind Power 
94. Cathodic Protection 
95. Fuel Cells 
96. Virtual Instrumentation 
97. Stirling Radioisotope Generator (SRG 
98. ome Automation 
99. PMDC Motor 
100. Integrated Vehicle Health Management Technology 
101. Solar Tower Technology 
102. Conditional monitoring 
103. Protection of overhead transmission against lighting 
104. Super conductor 
105. Remotely Queried Embedded Microsensors 
106. Electric Locomotive 
107. Fuzzy logic 
108. Fibre Optic Communication 
109. In-Memory Database 
110. Electrical & Electromagnetic interferance 
111. Condition Based Maintenance of Underground Cable Systems 
112. wind power generation 
113. Electrical vehicles 
114. ELECTRICAL 
115. Failure of Distribution Transformer 
116. Narrowband Powerline Communication 
117. Bluetooth? Wireless Technology 
118. Distributed Generation 
119. Data Compression 
120. Automated distribution system 
121. Micro electro-mechanical system 
122. HVDC back to back converter & transformer 
123. Utilization Of Solar Energy 
124. 33 KV gas insulated switchgear 
125. Cluster Meter System 
126. Geothermal 
127. Metamorphic Robots 
128. Faraday's Disk Generator 
129. Fuel cell vehicle 
130. Load sharing between the inverters operating 
131. Brush less DC motor 
132. Axial-field electrical machines 
133. Fusion 
134. Expert system as applied to power system 
135. RPM's flywheel power storage system 
136. Feeder protection 
137. Context Disambiguation on Web Search Results 
138. Tiny Switch 
139. Traction System 
140. Super Conducting Magnetic Energy Storage Systems 
141. H V D C converter 
142. Organic LED 
143. Biomedical Instruments (EEG 
144. Earth leakage circuit breaker 
145. MPEG Video Compression 
146. Energy conservation 
147. Direct torque Control Method for Speed control of Induction Motor 
148. Hydrogen The Future Fuel 
149. Static excitation system for alternator 
150. Architecture of an Electric Vehicle 
151. Nano Fuel Cell 
152. A report on series compensation 
153. Modern trends in thermal power station 
154. AVR in Alternator 
155. Blue ray Disc Technology 
156. Electromagnetic Bomb 
157. Fuel cell & Fuel cell power plant 
158. Advanced less-flammable transformer Insulating Fluid 
159. Power system relability 
160. Artificial intelligence in power station 
161. Automatic Change Over with Current Limiter 
162. RFID Systems 
163. Asynchronous systems 
164. Tele-Immersion 
165. Laser based application 
166. Static starting device 
167. Prediction of the closest margin to restore Power System Solvability 
168. 66 KV receiving station design 
169. Optical var Control 
170. Bioinformatics 
171. Tidel Power plant 
172. Digital Testing of High Voltage Circuit Breakers 
173. Micro Electro Mechanical Systems (REMEMS 
174. Static Relay 
175. Development Status of Superconducting Rotating Machines 
176. BiCMOS Technology 
177. Cable Modems 
178. Internet Protocol Television 
179. Storage battries 
180. Power supply for electrical traction drives 
181. Green Power 
182. Distributed Control System 
183. H V tester 
184. PLC 
185. Power Grid 
186. Supervisory control and data acquisition (SCADA systems in power stations) 
187. Power Theft Identification 
188. Micro stepping of stepper motor and application 
189. Night Vision 
190. PPTC Devices 
191. FACTS 
192. Explosive Flux Compression Generator 
193. Energy Saving Tube Light 
194. Power quantity standards 
195. Thermoelectric Coolers 
196. Automatic Meter Reading 
197. Phase Locked Loop 
198. Stenography 
199. Cryptography 
200. Magnetic Train 
201. Decentralized power sources 
202. Cable fault localization 
203. Public Key Encryption and Digital Signature 
204. Hybrid Electrical vehicles 
205. Superconducting Generator 
206. Performance Evaluation & EMI/EMC Testing of Energy Meter 
207. Static starting device for gas turbine 
208. Power frequency magnetic fields 
209. Electrolytic Hydrogen: A Future Technology for Energy Storage 
210. Solar cell 
211. Energy Audit 
212. Vector control of an induction motor 
213. Spintronics 
214. Molecular surgery 
215. Power distribution grid 
216. HVDC Technology 
217. Microprocessor based power theft identification 
218. Transient over voltages in electrical distribution system and suppression techniques 
219. Wireless power transmission 
220. Membrane Switch 
221. Extra high voltage transmission line 
222. Biometric Fingerprint Identification 
223. Stepper Motor & its Application 
224. Deregulation Of Energy Sector & [censored] Determination 
225. Renewable Energy Source Biomass 
226. Upgrading generator protection using multiple replay 
227. Electric field optimization of high voltage electrode based on neural network 
228. Line Reactors 
229. Relay Performance Testing With High Technology 
230. Two phase Neural Network 
231. Margin to restore Power System Solvability 
232. Contact less energy transfer system 
233. Matteran Energy 
234. Impacts of harmonics on power quality 
235. Protection through switchyard equipment 
236. Ultracapacitors 
237. Biosensors 
238. A technique for on-line detection of shorts in fields of turbine generator rotor 
239. Non conventional source (Geothermal 
240. 66 K V Switch Yard 
241. Broadband Over Power Line (BPL 
242. Perceptive computing 
243. Voltage Sag Analysis 
244. Terrestrial Photovoltaics (PVs 
245. Home Electrical Device Control HOWTO 
246. Satellite Television 
247. Neutral networks in process control 
248. Wireless fidelity 
249. Different Type of Excitation scheme on alternator 
250. Transformer Oil 
251. Buck Boost Transformer 
252. Dust collection & scrubing tech 
253. Herd coating Technology 
254. Solar power generation 
255. Less Flammable Transformer Insulating Fluids 
256. Modeling of Transformers with Internal Incipient Faults 
257. E H V transmission lines 
258. DC UPS 
259. Energy convection tower 
260. Power electronics 
261. Electrical fuses & its Application 
262. Speed control of DC shunt Motor Using PWM 
263. Introduction of Batteries 
264. Electrical Fuses, its types & Applications 
265. Maximum power point tracking 
266. Prospects Of Nanotechnology 
267. Fiber Optic Sensors 
268. Circuit Breaker Switching & Arc Modeling 
269. Lightning Protection Using LFA-M 
270. Medical imagining techniques 
271. High-Availability Power Systems 
272. Polymeric Positive Temperature Coefficient (PPTC 
273. Improving Electrical System Reliability with Infrared Thermography 
274. Hydrogen fuel cell in India 
275. Electroencephalogram 
276. Fuel Cells on Aerospace 
277. MOCT (Magnetic Optical Current Transformer 
278. Sensor less speed estimation of I M 
279. Operation & Maintenance of Substation 
280. Fault prediction & diagnoses 
281. Optical Antenna 
282. Satellite Solar power 
283. Alternator synchronization 
284. Electric cars 
285. Electronics Ballast 
286. Control of excitation system 
287. Protection of Distribution System 
288. Power system stability 
289. Superconducting Rotating Machines 
290. Position Emission Tomography 
291. Power factor improvement 
292. Fusion Technology 
293. Nanotechnology-Fueling the Chemical Industry?s Future 
294. Infrared Thermography 
295. Gas insulated Substations (GIS 
296. H V Testing of Circuit Breaker 
297. Solar Battery Storage Pump 
298. Flexible AC transmission 
299. Telluri Current 
300. Synchronization of alternator with grid 
301. Maintenance of Distribution Transformer 
302. Renewable energy 
303. Fractal Image Compression 
304. Testing of 3 phase induction motor and trouble shooting 
305. Radio Frequency Identification Sensors 
306. High voltage testing of Transformer 
307. Switched Reluctance Motor 
308. Pyroelectric Fusion 
309. Solar electric vehicles 
310. Hydrogen as an alternative fuel 
311. Compensation of Harmonic Currents Utilizing AHC 
312. Variable speed drives 
313. Combined cycle power plant 
314. Direct to Home 
315. Transformer Protection 
316. ISDN 
317. E-commerce 
318. Wavelet Transforms 
319. Lighting 
320. Fault location in Grounded and High resistance Grounded systems 
321. Distribution system relaying 
322. Magnetoencephalography 
323. CAES 
324. Wave energy 
325. HTS power cables 
326. Smart Card 
327. Capacitor voltage transformer 
328. DVD Combo ROM disc Technology 
329. Microprocessor Based Motor Speed Controller 
330. Calorimetric measuring systems: Problems and solution 
331. Magnetic Levitation & it’s Application 
332. Magnetic material used in static rotating machines 
333. Global Positing System 
334. Pumped Hydroelectric Energy Storage 
335. Nomad Expert Technician System 
336. Kalpsar Project Capturing Tidal energy 
337. Flywheel Energy Storage System (FESS 
338. Protection of transmission systems by using the global positioning system 
339. Condition Monitoring of Electrical equipment 
340. CT Scanning 
341. Nanotechnology-The Next Science Frontier 
342. Conducting polymers & plastic batteries 
343. Modern Trends & Evolution of C B 
344. Matrix Inversion Generator 
345. Lates IE Rules 
346. Missile guidance system 
347. Magnetic Levitation 
348. Surge current protection using superconductors 
349. High Voltage Transmission Line 
350. Excitation System for Alternator & AVR 
351. Written-Pole technology 
352. Transient Over Voltages 
353. Instrument Landing System 
354. Project Oxygen 
355. Speech Enabled Interactive Voice Response System 
356. Grid Connected PV Systems 
357. Energy Conservation in Electrical equipment 
358. Cascade Tripping 
359. High voltage test techniques 
360. Micro-power Generator 
361. Magnetic Levitation And Its Application 
362. Demand side management and energy audit 
363. High Voltage D C Transmission 
364. High Voltage A C Transmission 
365. Iris Scanning 
366. Conditional Access (CA System) 
367. Magnox 
368. Battery Charger 
369. E-mail alert System 
370. Internet through power lines 
371. Biomass Fuelled Power Plant 
372. Wireless Application protocol 
373. Development of Superconducting Rotating Machines 
374. Radio Correction Finder 
375. Secure Authentication Using Automated Biometrics 
376. Quality of Electrical power 
377. Direct Methanol Fuel Cell 
378. Design of solar power plant 
379. Protection Against Blackout 
380. Power Quality 
381. Tidal power 
382. Intelligent Substation 
383. Electrical and chemical diagnostics of transformer insulation 
384. Relay performance & testing 
385. Introduction to Data Mining and Knowledge Discovery 
386. SF6 circuit breaker 
387. Paralleling of LTC transformer 
388. UPS 
389. Helms Pump Storage Plant 
390. Speech Synthesis 
391. Brushless Alternators 
392. Transmission for Offshore Wind Farms 
393. Energy Saving Fan 
394. AC Cable Versus shos Cable Transmission for Offshore Wind Farms 
395. Universal Current Sensor 
396. Controller Of Electric Vehicle 
397. Testing of transformers 
398. Fiber optical sensors 
399. ANN Based Power System Restoration 
400. V/F method of speed control 
401. Technique for Online Detection of Shorts in Fields 
402. Microprocessor based alternator synchronization 
403. Lighting protection of over head 
404. Microprocessor Based Protective Relays 
405. Different types of energy storage system 
406. PLCC 
407. PPTC Devices for Protection of Battery Packs 
408. Robotics and its Applications 
409. Micowave genration & its application 
410. Fusion Energy 
411. Variable Reluctance Motor Drive 
412. Satellite solar power station 
413. Navigation system 
414. Traction Drives 
415. Molecular Electronics 
416. Nano Technology 
417. Losses reduction system in power 
418. HVDC Technology and Short Circuit Contribution of HVDC Light? 
419. DSP For Motor Control 
420. Generator protection 
421. Mercury removal in coal burned power plants by electro catalytic oxidation 
422. 12 Phase Capacitor 
423. Transformers Internal Incipient Fault Model 
424. Numerical Relay 
425. Wave Power Devices 
426. Feeder Protective Relay 
427. Localization of faults 
428. Friction machines 
429. Microprocessor based X’mer Protection 
430. Effect of Under Frequency on Generating Units 
431. Data Acquisition System 
432. Linear Induction motor 
433. Static VAR (Voltage Ampere Reactive compensator) 
434. Electrowetting 
435. Fuel cell driven vehical 
436. Integration of IT in Machine Tools 
437. Robotics Sensor 
438. Production & protection against surges 
439. Opto Electric Battery 
440. High-availability power systems: Redundancy options 
441. Electro wetting 
442. Micro Power Electrostatic Generator (MEG 
443. Harmonic elimination techniques 
444. Growler 
445. Development & compensation of transm line 
446. Dual-Core Processor 
447. EHV AC Transmission 
448. Reactive power management 
449. Seasonal Influence on Safety of Substation Grounding 
450. Radial Feeder Protection 
451. Automatic voltage regulation of alternator used in UKAI PP 
452. Liquefied Natural G 
453. Train lighting on railways 
454. Compressed Air Energy Storage (CAES 
455. Latest trends in nuclear power station 
456. Energy transmission system for an artificial heart - leakage inductance compensation 
457. Automation of temperature rise test for switchgear 
458. Comparative Study Of Maximum Power Point Tracking 
459. EHV transmission system 
460. Iridium Satellite Phone 
461. Solid State Interlocking 
462. Electrocardiogram 
463. E-paper 
464. Bone growth using electrical simulation 
465. Internet telephony 
466. The global voltage regulation 
467. Magnox Nuclear Reactor 
468. Adaptive Piezoelectric energy harvesting circuit 
469. Review of Electricity Act -2003 
470. Vacuum Circuit Breaker 
471. ACSR & alloy 
472. Ocean Thermal Energy Conversion 
473. Optical current transducer & its fault location in substation 
474. Input Output Completion Ports 
475. Super conducting generator 
476. Motor Protection 
477. Numerical relays 
478. Power EC based distribution transformer 
479. User Authentication using Automated Biometrics 
480. Industrial fire safety 
481. Intrusion Detection With Snort 
482. Icing of Power Transmission lines 
483. Electronic Ballast 
484. Electronic Fuel Injection (EFI 
485. Tsunami Early Warning System 
486. E-Bomb 
487. Broadband Over Power Lines (BPL 
488. Condenser Bushing 
489. Wind Diesel systems 
490. Magneto hydrodynamic Power Generation Technology (MHD