Bil Electrical

March 21, 2024 Post a Comment

Bil electrical

There are two basic classifications of insulation strength: basic insulation level (BIL) or lightning-impulse withstand voltage, and power-frequency withstand voltage (often called “hipot” voltage).

What is BIL and SIL in electrical?

BIL: Basic Impulse Insulation Level defines the maximum crest impulse voltage that insulation will withstand repeatedly and without damage. SIL: Switching Impulse Level, same as BIL except with a longer switching surge, typically 200 – 2,000 microseconds.

What is Bil value?

Basic Insulation Level (BIL means reference voltage level expressed in peak (crest) voltage with standard 1.2/50 µs lightning impulse wave. Apparatus should be capable of withstanding test wave of basic insulation level or higher.

What is bil on a transformer?

What is BIL and how does it apply to transformers? BIL is an abbreviation for Basic Insulation Level. Insulation levels in electrical equipment are characterized by the withstand voltages used during the impulse test.

How is Bil level calculated?

	Basic insulation level, kV (standard 1.5- × 40-μs wave)
5.0	60	75
8.7	75	95
15	95	110
23	110	150

How is Bil determined?

The BIL depends upon many factors; lightning intensity, earthing resistance, soil conditions, equipment ratings, transmission line configuration, type of equipment, switching surges, etc., etc.

What is the BIL rating of a 25 kV class termination?

The cable terminating station shall be 25 kV class, 125 kV BIL, 1250 ampere (Alternate—1500 ampere) continuous current, suitable for use on 15.2/26.3 kV grounded wye max design systems.

What is insulation level in VCB?

Highest system voltage. 36 KV. Insulation level. 36 KV/70 KV/170 KV(P) Frequency.

What is basic insulation electrical?

Basic insulation is a single layer of insulation that provides protection from hazardous voltages. An example of basic insulation is the plastic insulation around each conductor of a common ac power cord.

What is impulse voltage?

impulse voltage means a wave of voltage which, without appreciable oscillations, rises rapidly to a maximum value and falls, usually less rapidly to zero with small, if any, loops of opposite polarity; Sample 1.

What is standard impulse wave?

A waveform that has a defined virtual front time and a defined virtual time to half peak value. NOTE 1 Impulse waveshapes may be given for either voltage or current.

What is insulation voltage?

The rated insulation voltage of an equipment is the value of voltage to which dielectric tests and creepage distances are referred. In no case shall the maximum value of the rated operational volatage exceed the rated insulation voltage and there is no withstanding time for it.

What is the power frequency withstand voltage?

ac power-frequency withstand voltage is 2 kV and 5 kV for the impulse withstand voltage. Ordinarily, 2 kV 1 min. ac withstand voltage is required for the insulations of secondary devices [32], [34].

What is lightning impulse test?

Impulse testing systems are designed to generate impulse voltages that simulate lightning strikes and switching surges. The complete test system consists of a charging rectifier, impulse stages according to the “Marx Circuit”, an impulse voltage divider and impulse voltage measurement system.

What is switching impulse voltage?

Transient overvoltages accompanying sudden changes in the state of power systems, e.g. switching operations or faults, are known as switching impulse voltages.

What is the difference between functional and basic insulation?

Functional insulation — Insulation needed for the correct operation of the equipment. Basic insulation — Insulation that provides basic protection against electric shock.

What is the meaning of 1.2 50 μs?

The 1.2/50 is termed as the standard lightning impulse voltage having a front time of 1.2 µs ±30%, a time to half value of 50 µs ±20% and a peak value tolerance of ±3 %.

What is double insulation?

(Electrical engineering: Electrical power) Double insulation is insulation that consists of both basic insulation and supplementary insulation. Equipment such as hand-held domestic electric drilling machines has the additional safety precaution of double insulation.

What is volt time curve?

The volt-time curve is a graph showing the relation between the crest flashovervoltages and the time to flashover for a series of impulse applications of a given waveshape.

What are 3 types of cable termination?

Soldered connections, wire-wrapping connections, crimp connections, compression terminations, and loop or “eye” connections are the most common types of terminations used.