How to connect current transformer and reactive power meter

1. It is the wiring form of a single current transformer.

Can only reflect the situation of single-phase current. It is applicable to the need to measure the balance of one-phase current or three-phase load. When one phase is measured, the three-phase condition can be known, and most of the ammeters are connected.

2, three-phase complete star wiring and delta wiring form.

The three-phase current transformer can accurately understand the three-phase load changes in time, and is often used in transformer differential protection wiring. Only use three-phase complete star-wired current acquisition for watt-hour meters in a direct neutral grounding system. The three-phase three-relay connection method can not only react to various types of phase-to-phase short-circuits, but also can react to single-phase ground short-circuits. Therefore, this wiring method is used for the protection of phase short-circuit protection and single-phase ground short-circuit in the neutral point direct grounding system.

3, two-phase incomplete star wiring form.

It is used most in practical work. It saves one current transformer and uses the combined current of phase A and phase C to form an inverting phase B current. The two-phase dual-relay connection method can respond to phase-to-phase short circuits, but it cannot fully respond to a single-phase ground short circuit, so it cannot be used for single-phase ground protection. This wiring method is used for neutral point ungrounded systems or arc suppression coil grounding systems for phase-to-phase short-circuit protection.

4, two phase difference current wiring form.

It is also used only in three-phase three-wire circuits. The neutral point is not grounded, and there is no neutral line. The advantage of this type of connection is that it not only saves a current transformer, but also uses a relay to reflect the various types of three-phase circuits. Phase-to-phase short-circuit faults, that is, three-phase overcurrent protection with minimal relays, save investment. However, when the failure mode is different, the sensitivity is different. This type of wiring is often used for phase-to-phase short-circuit protection in distribution networks up to 10kV. Due to the low sensitivity of this type of protection, modern times have rarely been used.