Surge Protection Capacitors
TRANSQUELL Surge capacitors are designed for protection of rotating electrical machines (large electrical motors‚ generators‚ etc)‚ connected to systems which are subject to voltage and switching surges. The magnitude of lightning and switching surges are often controlled by lightning arresters‚ but this form of protection may not be sufficient to protect the turn to turn insulation of rotating machines from steep fronted voltage waves. It is therefore essential to connect a capacitor between line and earth to modify the rate of rise of the surge voltage‚ ensuring the voltage is more evenly distributed across the insulation of the winding.
These capacitors are also used in conjunction with HT Bus–Ducts‚ i.e. Segregated Phase / Transformer–Generator Interconnection Bus–ducts.
Manufactured to exacting specifications of customers‚ based on application specific designs‚ these capacitors comply rigidly with international standards‚ IEC specifications and to ISS : 11548–1986.
Various Configuration Of Surge Protection Capacitors :
7.2 kV Surge Capacitor
12/24 kV Surge Capacitor
7.2/12/24 kV 3 Phase Surge Capacitor
24 kV Surge Capacitor Double Bushing Type
36 kV Surge Capacitor Double Bushing Type
Diagram Showing Steep & Modified Wave Forms :
Ratings :
Preferred rated outputs of Capacitors :
| Highest System Voltage kV | Surge Capacitor Voltage kV | Capacitance Per Phase μF (Microfarads) |
|---|---|---|
|
3.6 |
6 |
0.5 and 0.5 |
|
7.2 |
12 |
0.25 and 0.5 |
|
12 |
18 |
0.25 and 0.5 |
|
24 |
28 |
0.25 |
|
36 |
40 |
0.125 and 0.25 |
Preferred rated outputs of Capacitors & Arresters for use with rotating machines :
| Machine voltage rating (kV r.m.s) | Surge capacitor voltage rating (kV r.m.s) | Capacitance (μF) | Arrester effectively grounded (kV r.m.s) | Arrester not effectively grounded (kV r.m.s) |
|---|---|---|---|---|
|
0.65 |
0.65 |
1.0 |
0.65 / 0.75 |
0.65 / 0.75 |
|
2.4 |
2.4 |
0.5 |
3.0 |
3.0 |
|
4.16 |
4.16 |
0.5 |
3.0 |
4.5 |
|
4.8 |
4.8 |
0.5 |
4.5 |
6.0 |
|
6.9 |
6.9 |
0.5 |
6.0 |
7.5 |
|
11.5 |
11.2 |
0.25 |
9.0 |
12.0 |
|
13.8 |
13.8 |
0.25 |
12.0 |
15.0 |
Operating Conditions :
- Installation : Indoor / Outdoor.
- Mounting : Horizontal / Vertical.
- Ambient Temperature : 50°C.
- Altitude : 1000 meters above sea level.
Operating Conditions :
All Surge Capacitors are tested in accordance with IS : 11548–1986.
Routine Tests Conducted :
- Measurement of capacitance.
- Dielectric loss angle test & Capacitor losses test.
- Voltage test.
- Test for efficacy of discharge device.
- Sealing test.
Type Tests :
- Thermal stability test.
- Impulse voltage test.
- Short circuit discharge test.
- Verification of container protection against corrosion.
- Drop hammer test for bushing seal.