Live Line Capacitors
Morgan Technical Ceramics Electroceramics (MTC Electroceramics) has long experience of the manufacture of ceramic capacitors for high voltage DC and power frequency applications. These products are used all over the world in onerous service conditions, and are backed by rigorous testing procedures to ensure the electrical integrity and long service life of such components.
| Over one million capacitors of the categories described here have been successfully used in Live-Line Indication applications. MTC Electroceramics has decades of involvement in high voltage system practices and the design of capacitors for those environments. The capacitors described in this section are used in circuitry indicating the presence of voltage on conductors. A capacitor voltage divider enables a small neon lamp to be illuminated or alternatively the low voltage signal may be used to feed a sensing circuit which monitors for supply failure and circuit condition . |  | |
| Theory |
| Fig.1 | Fig.2 |
 |  |
| C1 = High Voltage Series Capacitor C2 = low Voltage Shunt Capacitor |
| Material Characteristics | Dielectric | |||
| Units | K1500 | K2100 | K3500 | |
| EIA Category | Z5U | X7R | Y5U | |
Dielectric Constant  r @ 1kHz, 20°C LV | approx 1500 | approx 2100 | approx 4300 | |
| Dielectric Constant r @ 50Hz, 0.35kV/mm 20°C | approx 1650 | approx 3000 | approx 5200 | |
| Typical Dissipation Factor @ 1kHz 20°C LV | % | =<0.5 | =<2.0 | =<1.0 |
| Insulation Resistance @ 500V, 20°C | ohm | >=1010 | >=1010 | >=1010 |
| Ageing Rate per decade hour | % | -3 | -2.5 | -3.5 |
| Capacitors for encapsulation by the user.
|  |  |
| All Dimensions in mm | Style A | Style B |
Style A
| Type | Cap Value | Cap Tol | Dielectric | Voltage rating | System Voltage | Voltage Test 1 Min | Voltage Test Impulse | Discharge Free Test | øD | L1 | L2 | Thread Size Socket |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| pF | kV rms | kV | kV 50Hz | kV pk | kV<5pC rms | mm | mm | mm | mm | |||
| 07849 | 250 | ±20% | K3500 | 7 | 12 | 30 | 60 | 8 | 17 | 50.5 | 30.5 | M4 |
| 07727 | 220 | ±20% | K3500 | 7 | 12 | 38 | 75 | 8 | 17 | 60 | 40 | M4 |
| 07724 | 150 | +20, -10% | K3500 | 15 | 24 | 55 | 140 | 26.4 | 17 | 81 | 61 | M4 |
| 07723 | 50 | ±8pF | K1500 | 15 | 24 | 55 | 125 | 25.0 | 17 | 81 | 61 | M4 |
| 07853 | 50 | ±10pF | K2100 | 15 | 24 | 55 | 125 | 26.4 | 12 | 81 | 61 | M4 |
| 07897 | 20 | ±20% | K200 | 8 | 12 | 38 | 75 | 13.2 | 25 | 56 | 40 | M4 |
| 07898 | 15 | ±20% | K200 | 15 | 24 | 50 | 125 | 26.4 | 25 | 82 | 62 | M4 |
Style B
| Type | Cap Value | Cap Tol | Dielectric | Voltage rating | System Voltage | Voltage Test 1 Min | Voltage Test Impulse | Discharge Free Test | øD | L2 |
|---|---|---|---|---|---|---|---|---|---|---|
| pF | kV rms | kV | kV 50Hz | kV pk | kV<5pC rms | mm | mm | |||
| 55530 | 150 | +35, -15pF | K3500 | 14 | 24 | 55 | 140 | 15 | 17 | 61 |
| 55701 | 50 | ±10% | K1500 | 14 | 24 | 55 | 140 | 15 | 17 | 61 |
| 55559 | 50 | ±10% | K2100 | 14 | 24 | 55 | 140 | 15 | 12 | 61 |
Notes
1. Terminals are soldered to the ceramic parts with 220°C melting point solder
2. Capacitors of this type have been used in transformer oil and in SF6 gas. In these cases we would recommend a paint coating on the otherwise bare ceramic surfaces.
3. The usual end product is a resin cast capacitor stand-off for bus-bar or link support of appropriate height for the achievement of the system requirements of flashover and creepage distance etc.
4. Additional metal connectors can be attached to the above on request.
| Capacitance Dividers Many users prefer to have Morgan Electro Ceramic supply in the same moulding, not only the high voltage capacitor but also a lower voltage capacitor of larger value. This shunts the signalling circuit of the live-line indicator and prevents the incidence of high voltage at the tapping point should the indicating lamp loosen in the socket or become open circuit. In the type of construction shown a heavily insulated HV lead is taken from the capacitor at the top. The construction is such that the lead contributes to a higher creepage distance such that this range is useful for certain distribution applications as well as for the requirements of mining switchgear. |  |
| The following descriptions apply to integral dividers primarily designed for mining switch gear applications. However, certain distribution switchgear requirements are met by virtue of their electrical withstand properties. |
| Type | Cap Value | Cap Tol | Dielectric | Voltage Rating | System Voltage (Distribution) | System Voltage (Mining) | Voltage Test 1 Min | Voltage Test Impulse | Discharge Free Test |
|---|---|---|---|---|---|---|---|---|---|
| pF | % | kV max | kV | kV | kV 50Hz | kV 50Hz | kV<5pC rms | ||
| 07529 | 375/5000 | ±10 | K3500 | 4 | 3.6 | 7.2 | 20 | 40 | 5 |
| 07517 | 250/5000 | ±10 | K3500 | 7 | 7.2 | 12 | 28 | 60 | 8 |
| 07590 | 250/5000 | ±10 | K3500 | 7 | 12/17.5 | 38 | 95 | 8 | |
| 07596 | 1000/5000 | ±10 | K3500 | 4 | 3.6 | 7.2 | 10 | 40 | 5 |
| 07574 | 900/2500 | ±20 | K3500 | 2 | 3.6 | 10 | 20 | 3 |
(Cap Value at 50Hz, +20°C)
 | Capacitors of Special Configuration These are shapes produced to meet special space limitation factors and are often custom-made for the user. |  |
| Type | Cap Value | Cap Tol | Dielectric | Voltage Rating | System Voltage (Distribution) | System Voltage (Mining) | Voltage Test 1 Min | Voltage Test Impulse | Discharge Free Test |
|---|---|---|---|---|---|---|---|---|---|
| pF | % | kV max | kV | kV | kV 50Hz | kV 50Hz | kV<5pC rms | ||
| 07560 | 1000 | ±20 | K3500 | 2 | 3.6 | 10 | 20 | 3 | |
| 07573 | 250 | ±20 | K3500 | 7 | 7.2 | 12 | 28 | 60 | 8 |
| 07576 | 375 | ±20 | K3500 | 7 | 7.2 | 12 | 28 | 60 | 8 |
| 07580 | 1000 | ±20 | K3500 | 7 | 7.2 | 12 | 28 | 60 | 8 |
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