BIL
Basic Impulse Level...
Basic Impulse Level...
B.I.L. stands for Basic Impulse Level for the transformer. It should be on the faceplate of the transformer.
BIL stands for Basic Impulse Level, it is the impulse voltage or power ( in the case of testing a transformer) or surge voltage in the case of lightning or switching, that a transformer or any other electric device is able to with stand. It refers to maximum voltage a device can with stand with out insulation breakdown which leads to a short circuit.
BIL
Basic Impulse Level...
Basic Impulse Level...
B.I.L. stands for Basic Impulse Level for the transformer. It should be on the faceplate of the transformer.
BIL is basic insulation level as per you or in other words it would be "basic impulse level" which implies the limit up to which an insulator could withstand impulse due to lightning strikes. Impulse is generated on the insulation due to the high voltage surges and spikes due to lightning strikes. BIL is generally much higher as compared to power frequency withstand voltage. In other words BIL is lightning Impulse withstand voltage. Impulse withstand voltage is the voltage that is generated due to switching operation and it's much higher than power frequency withstand, but BIL or the lightning withstand voltage is a the voltage level that an insulation can withstand during surge or lightning strikes.
BIL stands for Basic Impulse Level, it is the impulse voltage or power ( in the case of testing a transformer) or surge voltage in the case of lightning or switching, that a transformer or any other electric device is able to with stand. It refers to maximum voltage a device can with stand with out insulation breakdown which leads to a short circuit.
BIL (Basic Impulse Level) is the maximum voltage a insulation system can withstand without breaking down. For 600 volts, the BIL would typically be around 10 kV or higher, while for 480 volts, it would be around 8 kV or higher. BIL is important for protecting equipment from voltage surges and ensuring reliable operation.
Please refer Chapter 1, Page 2 of "Insulation coordination for power systems" by Andrew R. Hileman that gives a good description of the term BIL and BSL (Basic Switching Impulse Withstand Voltage).
BIL or basic impulse insulation level is the dielectric insulation gradient of a material tested to withstand the voltage stress at a voltage impressed between the material and a conductive surface beyond the BIL rating, an electric tracking starts to occur which will then result into an arcing flashover to the conductive surface. In addition it is the capacity of an equipment to withstand mechanical stress..like lightning strike without causing any damage to the equipment...
Also known as basic insulation level (BIL): A specific insulation level, expressed in kilovolts, in accordance with which the complete system (including the line pole insulation to earth at every pole, the switchgear, the line isolators and reclosers, and the substations connected to the system, including their transformers) is designed and constructed. (NRS 039:1995)
Yes. The IEC 60071.1 Std states a diminish withstand of aprox of 1% every 100mts above 1000mts. For example: for a 13.8kV system the insulation level should be of 95kV (interior). If the installation is going to be at 1,500mts then de minimum insulation level of your equipment must be: 95kv/(1-0.01*(500/100)) = 100kV BIL. The next std value for BIL is 125kV.
Lightning Impulse withstand test is a destructive test carried out on high voltage switchgear. It is classed as a destructive test as each shot damages the insulation and lays carbon tracks. The Energy Networks Association Technical Specification (ENA-TS) 41-36 states the BIL (basic Impulse level) Required for the Voltage rating of the piece of switchgear rated up to 36kV. For example an 11kV switchgear will have a BIL of 95kV. Switchgear which include a Vacuum circuit breaker must have a second means of isolation, ie a disconnector. This disconnector can be a two position (mains on, off) or three position (mains on, off, or earth on) disconnector operated off load which is in series with the Circuit breaker. To pass the test 15 shots at +95kV and 15 shots at -95kV are fired at all positions of the disconnector and only 2 out of the 15 (and not the last 5) shots can flash over to earth. For example if the disconnector was in the off position one side will be connected to the impulse generator and the other side will be earthed. Positive and Negative shots will be fired and the impulse can not flash through the air gap to the earthed side of the disconnector. This proves the isolation gap inside the disconnector has a BIL rating of 95kV. Therefore if the incoming side of a switchboard is live and the outgoing side is isolated for maintenance. There can be a transient impulse on the live side of the circuit and it will not flash across the isolating gap and endanger anyone working on the dead side of the circuit