Circuit breaker anti-jump loop function and typical wiring and application precautions - News - Global IC Trade Starts Here.

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Circuit breakers are important primary devices in power systems. At present, there are many domestic manufacturers. The arc-extinguishing principle, operating mechanism and control loop are also diverse, each with its own characteristics, especially the design of the anti-jump circuit is very different. How to combine the control loop and the anti-jump loop is the most concerned issue for engineers and technicians. Based on years of field experience and application practice, this paper introduces the current popular anti-jump circuit wiring and principle, and discusses the problems in the application.
1 The role of the anti-jump circuit
A1 Prevent the switch of the control switch or the automatic device from failing to return in time (for example, the operator does not release the handle, the closing contact of the automatic device is stuck) and just closes the faulty line and equipment, causing the continuous closing of the circuit breaker. .
B1 An important function of the current-starting and voltage-holding electrical anti-jump circuit is to prevent the improper adjustment of the auxiliary contact of the circuit breaker due to the trip circuit (the displacement is too slow), causing the protection of the outlet contact to be broken and burned first. This phenomenon is intolerable for microcomputer protection devices, and this is often overlooked.
2 Typical connection of anti-jump circuit Commonly used anti-jump circuit has series anti-jump circuit, parallel anti-jump circuit, spring energy storage anti-jump circuit, trip coil auxiliary contact anti-jump circuit and so on. Multi-circuit type anti-jump circuit breakers are often used in domestic circuit breakers. Among them, the series anti-jump circuit is the most reasonable and the most widely used. In addition to the anti-skip function, it also has the advantage of preventing the arc of the outlet joint from being broken and burned. This is also an indispensable technical condition for the application of the microcomputer protection device. Other anti-jump circuits only have the function of preventing the circuit breaker from jumping. When the trip coil auxiliary contact type anti-jump circuit performs the anti-skip function, the trip coil may be burned if it is charged for a long time.
2.1 Series anti-jump circuit The so-called series anti-jump, that is, the anti-jump relay TBJ is started by current, and the coil is connected in series in the trip circuit of the circuit breaker. The voltage holding coil is connected in parallel with the closing coil of the circuit breaker. When the switch is connected to the faulty line or equipment, the relay protection action, the protection outlet contact TJ is closed, at this time, the current coil of the anti-jump relay TBJ is started, and the circuit breaker trips, the normally closed contact of the TBJ opens the closing circuit, and A pair of normally open contacts turns on the voltage coil and holds it. If the SK (5-8) or HJ contact cannot be returned at this time and the closing command is issued, the circuit breaker cannot be closed because the closing circuit has been disconnected, thus achieving the anti-jumping purpose. In addition, when the TBJ is started, its normally open contact parallel to the protection outlet is closed and self-protected, until the "compulsory" circuit breaker normally opens the auxiliary contact displacement, effectively preventing the protection of the outlet contact from arcing. The series anti-jump circuit is shown in Figure 1.

2.2 Parallel anti-jump circuit The so-called parallel anti-jump, that is, the voltage coil of the anti-jump relay KO is connected in parallel to the closing circuit of the circuit breaker (as shown in Figure 2). For example, when a permanent closing command exists, the output of the closing rectifier bridge is turned on by Y3, S2, S3, S1, KO (2-1). After the circuit breaker is closed, the auxiliary contact S3' connected in parallel in the closing circuit is closed, and the anti-jump relay KO is activated. The KO contact is switched from the 2-1 position to the 4-1 position, and the closing circuit is opened and held. If the line or equipment fails at this time, the relay protection action trips. However, since the closing circuit has been reliably disconnected, the switch jump is prevented.

2.3 Spring energy storage type anti-jump circuit As shown in Figure 3, when a permanent closing command arrives, the closing current is turned on by SK or HJ through S3, K1, K1, S2, S1, YA 1 . After the closing, the spring mechanism starts to store energy. The spring energy storage auxiliary switch S3 connected in parallel in the closing circuit is connected to the anti-jump relay K1. The normally open point of K1 is self-protected, and the normally closed point is closed. If the line or equipment fails at this time, the relay protection action trips, and since the closing circuit has been reliably disconnected, the switch jump is effectively prevented.

2.4 Trip coil auxiliary contact type anti-jump circuit As shown in Figure 4, when a short-circuit fault occurs during the closing process, the protection device trips the circuit breaker, and the normally open auxiliary contact TQ 2 operated by the trip coil is closed, keeping the trip coil continued. power ups. The normally closed auxiliary contact TQ 1 of the trip coil is opened, and the closing circuit is cut off. If the closing command continues to exist at this time, the circuit breaker will not be closed again. After the closing command is released, the trip coil loses power and the wiring returns to its original state.

3 Problems to be aware of during application
A1 For the circuit breaker without anti-jump device, an electric anti-jump circuit should be installed. The performance of the series anti-jump circuit is optimal. It should be used preferentially, and it can receive two effects.
B1 The starting current coil of the series anti-jump relay should be selected according to the sensitivity not less than 2, and the polarity of the current coil and the voltage coil should be the same when installing.
C1 When there is an electrical anti-jump circuit inside the protection device and the switch operation mechanism, it is recommended to use the anti-jump circuit inside the protection device, and the anti-jump circuit in the operation mechanism is removed, so that the use is reliable and easy to maintain.
D1 For the spring energy storage operating mechanism, some people think that its energy storage mechanism itself has anti-jump function, it seems that it is no longer necessary to add an electrical anti-jump circuit. However, the energy storage mechanism does not prevent the switch jump caused by the closing of the closing contact, and does not prevent the arc of the protection outlet from being burnt, so it is better to install an electrical anti-jump circuit.