Switchgear consists of busbars, circuit breakers, disconnectors and earthing switches. There are various connections and contacts within the switchgear. Poorly maintained or damaged contacts can cause arcing, single phasing or even fire which can lead to the total loss of the asset.
Therefore, it is common practice to conduct contact resistance measurements to ensure that the connections have been made with the appropriate contact pressure.
Additionally, the insulation of circuit breakers within the switchgear has to be tested. These assets are frequently exposed to HV stresses, switching currents and very high fault currents, which heat up the circuit breakers and impact on the insulation material.
The Omicron CPC 100 Multi-functional Primary Test System can measure contact resistance by injecting a current of up to 400 ADC into the contacts and measuring the voltage drop (using the 4-wire method). The resistance value can be compared to the value given by the manufacturer as well as to previous records.
For power / dissipation factor (tan δ) measurements of circuit breakers, the CPC 100 is combined with the Omicron CP TD1. Measuring this factor over a wide frequency range, in addition to mains frequency, helps to better assess the insulation condition.
For testing of circuit breakers or load breaker switches with integrated overcurrent elements, the CPC 100 can inject AC primary currents up to 800 A, and measure the time from the start of the injection to the interruption of the current.
Switchgear / circuit breaker testing
• Contact resistance up to 400 ADC
• Bushing: power / dissipation factor (tan δ) + insulation capacitance 12 kV, 300 mA, frequency from 15 Hz to 400 Hz, with CP TD1
• Overcurrent relays with primary injection (MV) up to 800 A or 2 000 A with CP CB2, 5 kVA output power
• Circuit breaker: power / dissipation factor (tan δ) up to 12 kV, 300 mA, frequency from 15 Hz to 400 Hz, with CP TD1
• Insulating fluids: power / dissipation factor (tan δ) up to 12 kV, 300 mA, with CP TD1