A brief introduction to the electrical primary automatic reclosing device
A primary recloser is defined as an automatic recloser that does not reclose again if the reclosing is unsuccessful. The automatic reclosing device is an automatic device that automatically puts the circuit breaker that jumps open due to failure as needed. According to the number of reclosing, there are one recloser and multiple reclosers, and according to the number of phases, it is divided into three-phase and single-phase automatic reclosing.
Its content is shown in the image.
In the diagram, the 1 s a switch is the circuit breaker control switch.
2 s a is the automatic recloser selector switch for putting and unloading a r d device. The k a r in the diagram is the reclosing relay.
The DH2 reclosing relay is used as a reclosing element in the realization of three-phase primary reclosing wiring on transmission lines.
Analyze the automatic reclosing process after a fault trip.
When the system is functioning normally, the loop through which the flow flows starts from this + W c and goes through 2 s a
The automatic recloser selector switch goes to resistor R 4, then through capacitor C, and finally back to - W C.
Capacitor C is charged with resistor 4R. In the process of capacitor charging, the current will pass through 4R and capacitor C, and capacitor C will gradually accumulate charge, store electrical energy, and gradually increase the voltage. The charging process ends when the voltage across the capacitor reaches the charging voltage. In this process, 4R has the function of limiting the current to prevent the capacitor from being overcharged in a short period of time, thus protecting the safety of the capacitor and the circuit. Indicator light h l
Bright, it means that the bus voltage is normal, the capacitor is in the charging state, and at the same time, it can also indicate the operating status of the power system.
When there is a fault in the power system.
In the figure, the quick-break protection or over-current protection action in the relay protection trips the circuit breaker and removes the fault.
After tripping, due to the closure of the 1,2 contacts of Q F, the KT time relay will be energized to act, KT
The 3,4 contacts are closed after a time delay, and the capacitor C is on the km line.
Circle discharge, so that km action;
In the figure, the resistor 5R is connected to the K T loop to limit the current flowing through and keep the K T in action. After the km action, its contacts are closed. After the km current coil, the contacts of KS, XB, KTL, the 3,4 contacts of QF, and then the closing contactor 1km action. Reclose the circuit breaker.
If the fault is instantaneous, the recloser closes successfully. At the same time, due to the closure of the 7,8 contacts at km, the rear acceleration relay 2km will also start.
If the fault is permanent, the relay protection action, 1kt normally open and closed, after a delay of 2 km to open the contact, the tripping circuit is switched on and tripped. Since capacitor C is already connected in parallel with the KM coil, capacitor C will not be charged to the power supply voltage value, so it will automatically be reloaded.
The closing is only re-closed once.
Electrical primary automatic reclosing device related to the relevant coordination mode.
When tripping manually, the recloser should not be reclosed.
The capacitor is connected in parallel with 6R, and C cannot be reclosed because it cannot charge the power supply voltage.
Anti-Trip Function: When the ARD coincides with a permanent fault, the circuit breaker will trip again, the KTL's current coil will be activated due to tripping, and the KTL's contacts will close and self-lock. KTL voltage coil is energized and maintained, and the point of KTL is disconnected, cutting off the closing circuit to prevent jumping.
The way in which ARD works with relay protection.
The main way to cooperate with ARD and relay protection is currently the acceleration protection mode after the power supply and distribution system is Chongclosing.
Acceleration protection after reclosing means that when a fault occurs on the line, the protection first trips in a selective manner. After the circuit breaker is closed, if it coincides with a permanent fault, the protection action will be accelerated and the fault will be removed.