Hi All,
The Motor protection Relay NC (Normally Close) or NO (Normally Open) usage will be based on type of motor On/Off switching. This is core electrical engineering best practice since the beginning.
If Contactor is used for switching of Motor, then to energize contactor coil NC is best...
Hi all,
Recently I come across following technical specification clause for MV or LV motor (LV motors can be considered as > 100 kW rating)
The clause details are as follows
....Electric motors shall be suitable for two (2) successive starts with the motor already at full load working...
Hi all
Recently we procured Exide make 100 Ah, 2 V - 55 nos to supply motive power to switchgear. We asked type test certificates of 100 Ah, 2V cells. They provided 400 Ah, 2V (higher rated) type test certificates and mentioned 100Ah, 2V and 400 Ah, 2V cells are same model.
Can anybody...
Dear Folks,
PV Solar Power plant has two voltage levels- 33kV and 0.4kV. Solar PV plant is connected to remote end 33kV sub-station through 33kV cable. Local 33/0.42kV transformers are used for auxiliary power supply to solar farm. Ground fault currents at 33kV and 0.4kV voltage levels are 2kA...
Hi Linspire
In practice, Number of OLTC switching per day depends on
1. The location of the transformer
Power generation plant's, Grid transmission transformer's OLTC requires less operations
Distribution trasnformer in Substation (not in power plants) OLTC require more number of oeprations...
Hi ART007
As per your technical details. The following option is essential to keep safe and meet long life of the transformers.
1. After successful autoclosure and tap adjustment, ALL transformer remains in Auto mode.
In fact while paralleling it is highly essential to ensure transformer...
Hi all
In general, In a power plant (capacity 100 MW to 4000 MW) the following equipment exists. Here power plants are Gas based or coal based.
Emergency Diesel Generator and Black start Diesel Generator.
Now I would like to know Why can not we club together and install a Black start diesel...
System voltage: 3.3kV (L-L)
Neutral Resistance: 19.0526 Ohms
Ground fault current:100A (through each neutral circuit)
If two units are in operations, total ground fault current: 200A, however the ground fault current in each neutral circuit is 100A
Question is incomplete...Protection is completely depending on reliability and safety of the system. In order to design the protection, need to know down stream and upsteam network system, criticality of the supply etc., Moreover you may need to mitigate harmonics as well based on the type of...
Though total ground fault current is 200A, the current through each neutral is 100A only.... Then the maximum current through the sensitive earth fault relay is 100A... but ETAP is showing 200A in the senstive earth fault relay clipping current page... Based on this current,TCC graph shall clip...
Dear Folks,
Greetings...
In a small Isolated network with two generators are connected to a bus directly (without transformers) and operating in parallel. Each generator's ground (Earth) fault current is limited to 100A due to neutral ground resistor. Each generator has a neutral CT and...
I have just now read one article that "if motor starting current is more than 200A for 11kV motor, surge capacitor is not required to consider"...I am thinking that how come this is link to current chopping surges???
Source, section-V C of the link...
Fine... Let us assume transformer (Dyn11) is located remotely and neutral is solid grounded....If there is a ground fault at another remote location where load is connected, obviously GPR should not be more than Ph-E voltage for load side ground fault, where earth is referring to neutral point...
