Megger, UK SCITS 50 D Secondary Current Injection Test Set

• Variable 50-A a.c. output test current and 240-V a.c./d.c. auxiliary voltage output
• Sinusoidal constant current source that eliminates the need for waveform correction
• Integral timer for checking protection relay operation

The SCITS50D Secondary Current Injection Test Set has a maximum rating of 50 A/0,46 kVA and incorporates a timer. It is designed for testing electricity supply protection systems and particularly measuring the operating times of relays involved in them. Current from the main a.c. terminals is completely variable by use of the output control. The output test current is maintained constant and essentially independent of the load impedance; also, its sinusoidal waveform is regulated so that extra filtering is not necessary. Two independently controlled auxiliary outputs, 240 V a.c. and 240 V d.c. are included. These enable directional relays to be fully tested or can be used as a power supply. APPLICATIONS The SCITS50D is primarily intended for testing protection systems that include IDMT relays. However, it may be suitable for testing systems incorporating thermal overload, instantaneous and directional relays, so long as the thermal shutdown limits are not exceeded. Protective devices such as relays, overload coils and circuit breakers must be checked at regular intervals while in service. This routine checking ensures that they are always ready to operate should a fault occur in the equipment they are protecting. Routine secondary current injection testing with the SCITS50D will quickly detect faulty or incorrectly adjusted protection devices and therefore may prevent damage to plant equipment and injury to personnel. An important part of the correct functioning of a protective system is the time taken for the relay to operate. The integral timer of the SCITS50D, with the option of control by a remote pushbutton, means that the operating time of a protective relay can be easily and conveniently measured.