Discussion on the application of jump locking of c

Discussion on several applications of circuit breaker jump locking

1. Circuit analysis of jump locking circuit

electrical jump locking circuit is usually realized by jump locking relay. Figure 1 is the wiring diagram of jump locking circuit applicable to the circuit breaker with one tripping coil. The jump locking relay TBJ has a current starting coil tbj/i, a voltage holding coil tbj/u, two pairs of dynamic making contacts tbj1, TBJ 4 and two pairs of dynamic breaking contacts TBJ 2, tbj3, tbj/i connected to the tripping coil circuit of the circuit breaker, tbj/u connected to the closing circuit of the circuit breaker, tbj1 used for current self holding, tbj2, tbj3 connected in series into the closing circuit after being connected in parallel

when the tripping relay TJ acts to start tripping, tbj/i is excited, TBJ acts, tbj1 is closed, and the tripping command is maintained until the circuit breaker is disconnected. At the same time, tbj2 and tbj3 open the closing circuit, tbj4 is closed, and the voltage self holding circuit of TBJ is ready. If the manual closing relay contact SHJ or automatic reclosing contact zhj is closed before the circuit breaker is disconnected, that is, before the TBJ returns, the TBJ will continue to be in the disconnected state through the closed TBJ 4 and SHJ or zhj, that is, tbj2 and TBJ 3, so as to ensure that the circuit breaker will not be closed, so as to achieve the purpose of jumping and closing people's requirements for material mechanical property test and continuously improving the lock

Figure 1 electrical jump locking wiring diagram

2. Technical requirements of jump locking relay

2.1 current starting value

according to the anti accident measures of the Ministry of electric power industry in 1984 and the regulations of the secondary circuit design specification of power system, the current starting value of jump locking relay should match the tripping current of circuit breaker, and its current starting value should not be greater than 50% of the tripping current of circuit breaker, That is, when tripping, the current of tripping circuit should be greater than 2 times of TBJ starting current to ensure that the reliability coefficient of TBJ current is greater than 2

2.2 voltage drop of current coil

according to the above provisions, the voltage drop of the current coil of the jump locking relay should be less than 5% of the rated voltage of the operating circuit

2.3 voltage action value

according to the regulations, the voltage action value of the jump locking relay should not be greater than 70% of the rated DC voltage of the operating circuit, so as to ensure the reliable action of TBJ when the operating DC power supply voltage fluctuates within the specified range; At the same time, the TBJ voltage action value should not be less than 50% of the rated DC voltage of the operating circuit, so as to ensure that the TBJ will not misoperate when the operating DC power circuit is grounded

2.4 contact performance

tbj's contact performance should be the same as that of the outlet intermediate relay in the relay protection device. According to the power industry standard, the contact performance of the outlet intermediate relay in the relay protection device should meet the following requirements: return characteristics, return value ≥ 10% of the rated value (for dry spring relay, return value ≥ 70% of the rated value is required); Closing capacity, DC circuit 220V, 5 A; Mechanical life, 105 actions without load; Contact resistance, measured with a milliohmmeter ≤ 0.1 Ω; ≤ 0.5 Ω when measured with a digital multimeter; ≤ 0.1 Ω when measured by current voltage method

2.5 insulation performance

a. when the same group of contacts is disconnected, it can withstand power frequency 1000V voltage for 1min

b. the conductive parts without electrical connection can withstand power frequency 2000V voltage for 1min

c. between all conductive parts and mounting frames, it can withstand power frequency 2000V voltage for 1min

3. Composition of jump lock relay starting circuit

3.1 change the parameters of relay current coil

generally, the current type relay with current type action coil is selected as the jump lock relay TBJ, and its current coil current action value is selected according to the tripping current of the circuit breaker to ensure the action sensitivity of the relay. The relay current action value designed for this requirement is specified as 30% - 50% of the nominal rated value. As long as the relay current is selected to be consistent with the circuit breaker current, the requirement of relay sensitivity can be met

the advantage of selecting current type relay as jump locking relay TBJ is that the jump locking circuit wiring is simple, and the current coil of TBJ can be monitored through the closing position relay hwj. In the process of operation, if TBJ is disconnected, hwj will send an abnormal alarm signal for timely processing. Its disadvantage is that when the tripping current of the circuit breaker changes, the relay with corresponding current specification must be replaced, which is more troublesome

3.2 relay coil and parallel branch

in order to reduce the workload of changing the TBJ parameters of jump lock relay due to the change of circuit breaker parameters, relevant technicians and manufacturing units have been looking for a method suitable for circuit breakers of various specifications. Among them, the method of shunt branch in parallel with voltage type relay in the voltage coil of relay is gradually being recognized. Its parallel branch can be composed of resistance, diode or regulator circuit respectively. The current starting circuit of jump lock relay composed of voltage type relay and parallel branch of resistance, diode and regulator is introduced below (as shown in Figure 2 (a) (b) (c))

Figure 2 TBJ current starting circuit wiring diagram

(1) the relay voltage Japan Toray company will enhance its PPS material production capacity coil and resistance parallel branch constitute

as shown in Figure 2 (a), the current starting value of relay j/i is 0.07 ~ 0.12 a, and the coil resistance is 10 Ω. The parallel resistors are generally divided into 4 groups, and one or several resistors can be connected with the connecting piece to adjust the shunt size, so as to change the action value of the relay and realize the matching with the tripping current of the circuit breaker. When using this circuit, attention should be paid to preventing the resistance from breaking. It is advisable to select a metal oxide film resistor with a power of 8 ~ 10W, which has high reliability

(2) it is composed of relay voltage coil and diode parallel branch

as shown in Figure 2 (b), the current starting value of relay j/i is 0.07 ~ 0.12A, and the coil resistance is 10 Ω. The four diodes in parallel are connected in series and then connected in parallel at both ends of the relay coil, and the midpoint of the two strings is connected. This wiring can ensure that when one of the diodes is open circuit, the circuit works normally and improve the reliability of the circuit. At the same time, the two branches can share large current to prevent diode damage caused by excessive current

after testing, according to this wiring, when the passing current is 0.25 ~ 10a, the voltage at both ends is 1.2 ~ 2.3V, and the current in the relay starting coil is 0.12 ~ 0.23a, which can not only meet the requirements that the voltage drop is less than 5% of the rated voltage, but also ensure the action sensitivity of the relay

(3) it is composed of the relay voltage coil and the parallel branch of the regulator tube

as shown in Figure 2 (c), the current starting value of relay j/i is 0.07 ~ 0.12A, and the coil resistance is 10 Ω. The rated regulated voltage of VS1 and VS2 is 1.5V and the rated current is 5A. Two regulators in parallel can improve the reliability of the circuit. The test shows that the circuit can meet the requirements that the voltage drop is less than 5% of the rated voltage and ensure the action sensitivity of the relay

the deficiency of the current starting circuit of the jump locking relay composed of relay coil and parallel branch is that the parallel branch is added at the end of relay coil 2, so the relay coil cannot be monitored. If the relay coil is disconnected, incorrect action will occur

4. Conclusion

the circuit breaker jumping locking device composed of electrical circuit will still be widely used in a revolution in the printing industry. The way of changing relay current coil parameters is the main way of application at present because of its simple wiring and easy monitoring; However, the mode of jump lock relay current starting circuit composed of relay coil and parallel branch is more popular with manufacturers and operators because it is easy to change parameters. However, due to the complexity of the circuit and the inability to monitor the relay coil, it still needs further experience and careful use. (end)