Introduction to universal circuit breaker controllers and other structures.

I. Introduction to universal circuit breakers.

Universal circuit breakers are used in AC 50Hz voltage 380V, 660V or DC 440V, current up to 3900A distribution networks for power distribution and protection of line and power supply equipment against overload, undervoltage and short circuit, etc. Under normal conditions they can be used for frequent line conversion, 1250A and below circuit breakers can be used in AC 50Hz voltage 380V networks to protect motors against overload and short circuit. Under normal conditions, they can also be used for infrequent starting of electric motors.

Second, universal circuit breaker components.

As the piggyback current is mostly above 630A and up to 6300A, the conductive part of the contact is enclosed in a cavity affected by support, insulation, expected high short-circuit current and strong arc energy. The housing material is stamped with a special DMC material. The conductive contacts of each phase are fitted with a special fast saturation converter. The current signal of the phase is transmitted to the controller.

Using a series of complex mechanical mechanisms to stretch the energy storage a large diameter spring, using the tripping mechanism, the main spring is unlocked and released from the draw position, and then the closing or tripping operation is executed.

The main spring and these connecting rods and springs that are integrated are called energy storage mechanisms.

The extension of the main spring can on the one hand be carried out manually with a handle.

More often it is done by means of a motor and a connected reduction gear mechanism, relying on the motor mainly to stretch the spring to store energy. Electrical operation, energy storage motor, MOE, the designations are somewhat confusing.

Three, pole contacts are connected to the energy storage mechanism

Universal circuit breaker energy storage mechanism.

The operating mechanism is a mechanical product. Because of the professional reasons learned, I think this part is more important than the control, so I read a lot.

Universal circuit breaker controller.

(1) Acquisition of signals.

Current.

a-phase transformer, b-phase transformer, c-phase transformer, n-phase transformer, transformer centre point earth transformer.

Returns: collection of current values IA/IB/IC/IN/Ig/In.

Voltage.

Voltage of phase a, voltage of phase b, voltage of phase c.

Return: the set of voltage values Uab, Uac, Ubc.

Frequency.

Returns: f.

(2) Universal circuit breaker data pre-processing.

This part is used to calculate power, power factor, active power, reactive power according to the voltage and current signals

The unbalance of the three-phase currents is calculated, the formulae are confidential.

This part is also used for the statistics of harmonics.

Calculation of _parameters.

Active power, reactive power dependent on power

higher harmonics, frequency.

Three-phase unbalance, overvoltage %, undervoltage %, overfrequency %, underfrequency %

Connection to the RAM fault rule database.

2. The universal circuit breaker controller is set by the customer.

If a short circuit occurs before starting the overload timer program // 15 minutes, the timer parameters here need to be shortened. Thermal memory function.

Overload signal if timer = 180 seconds and Ia > 2 In.

If a fault signal is received

User specified fault handling rules are submitted according to the type of fault.

1. Circuit breaker release: various functions ending with "protection".

2. Alarm (temporary) inactivity, signal issued. For example, the PAL pre-alarm function.

3, in conjunction with a lockout signal to the upper circuit breaker, coming up on its own.

4. System control to signal the disconnection of "insignificant" load circuits at the lower level of the circuit breaker.