When a fault such as a short circuit or current overload is detected by a protective relay, a trip impulse is sent to the circuit breaker. The circuit breaker must function as specified and interrupt the current as soon as possible or severe damage may occur. The damage caused by a malfunctioning circuit breaker can often be catastrophic, resulting in significant damage to the electrical system.
When a high current passes through a pair of mechanically independent metallic contacts, the resistance must be as low as possible. An increase in resistance can lead to additional degradation, as I2R losses will cause local heating of the contact surfaces. Our range of micro-ohmmeters measure both steady state and dynamic low resistance values. With test currents up to 600A available, logging and trending are also available on some models. We ensure that our Contact Resistance tests sets are portable, making them suitable for field measurements. Our contact resistance testers’ portability makes them ideal for a vast range of resistance testing across the entire LV, MV HV and EHV spectrum.
Primary current injection testing is utilised in high current/high voltage scenarios found at large electrical installations such as substations. A large current (between 100A and 20,000A depending on system specifications and test requirements) is injected directly on the primary side of the electrical system such as a circuit breaker. The objective of the test is to identify how the system operates under various levels of current load.
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