JPS6241462Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a thyristor circuit breaker applied to a DC circuit, and particularly provides a thyristor circuit breaker that prevents dangers due to charge in the circuit when inspecting the thyristor circuit breaker. This is what I am trying to do.

An example of an electrical circuit to which a thyristor circuit breaker is applied is a direct current power supply device typically used in subways. This DC power supply equipment used a DC high-speed circuit breaker, which is well known for interrupting the power circuit in the feeding system. In addition, thyristor circuit breakers are now being used in place of DC high-speed circuit breakers because of their difficulties in terms of maintenance and the like. As is well known, in such a thyristor circuit breaker, a forced arc extinguishing circuit consisting of an auxiliary thyristor, a commutating reactor, and a commutating capacitor is connected in parallel to the main thyristor of the thyristor circuit breaker, and the thyristor circuit breaker is connected in parallel to the main thyristor of the thyristor circuit breaker. In the case of predetermined selection and cutoff, this is done by decharging the charge that has been previously charged with a predetermined polarity through the auxiliary thyristor to the main thyristor side when the auxiliary thyristor is ignited. A problem with such a thyristor circuit breaker which performs steady operation is, for example, when the thyristor circuit breaker is removed from a feeder (main circuit busbar) during inspection. In other words, the circuit including the thyristor circuit breaker includes a commutating capacitor for the forced arc-extinguishing circuit, a capacitor for absorbing surges on the power supply (thyristor rectifier) side, and a capacitor for the snubber circuit connected in parallel to the auxiliary thyristor of the forced arc-extinguishing circuit. If there are various types of capacitors and these capacitors are charged, it will be extremely dangerous for workers during inspections. A method for preventing danger during such inspection work will be specifically explained using a conventional device shown in FIG.

Figure 1 shows only one circuit in the feeding system of a DC power supply device. In the figure, 1 is the main thyristor of the thyristor circuit breaker, 2 is the first commutating stopper diode, and 2 ₁ to 2 ₂ are the main thyristors of the thyristor circuit breaker. Resistors and capacitors forming a snubber circuit include an auxiliary thyristor 3 and resistors and capacitors 3 ₁ to 3 ₂ for the snubber. 4 is a second commutation stopper diode 4 ₁ - 4 ₂ is a capacitor and resistor for the snubber, 5 is a commutation reactor, 6 is a commutation capacitor, 6 is a charging current limiting resistor, 6 ₂ is a 6 ₃ is a rectifier circuit that rectifies the alternating current power from the charging power source 6 ₄ , and 6 ₅ is a discharging disconnector. 7 is a reactor that suppresses the di/dt of the discharge current, 8 ₁ is a current limiting resistor, and 8 ₂ is a stopper diode for preventing discharge. Thyristor rectifier 11 is used to stop power supply to the substation in the event of a short circuit accident.
₉₁ to ₉₂ are resistors for suppressing surges on the power supply side; Similarly, with a capacitor, 9 ₃ ~
9 ₄ is a resistor and capacitor for suppressing surges on the load (feeding line) side, 10 is a wheeling diode for circulating the energy on the load side 12 when the thyristor circuit breaker is cut off, and 10 ₁ to 10
₂ is a resistor and a capacitor for the snubber of the diode 10.

When inspecting a thyristor circuit breaker using a conventional device configured as described above, it is well known that the circuit breaker including the thyristor circuit breaker, shown by the solid line in the figure, is first removed from the feeder. However, prior to inspection, the commutating capacitor 6 of the forced arc extinguishing circuit is normally charged to a predetermined value with the indicated polarity, so first the discharge disconnector 6 is
₅ , the charge in the commutating capacitor 6 is discharged through the path of the discharge disconnector ₆₅ → the resistor ₆₂ . Here, the charged charge of the capacitor ₉₄ , which absorbs the surge on the load (feeding line) side, passes through the path of the capacitor ₉₄ → resistor ₉₃ → discharge disconnector ₆₅ → resistor ₆₂ → resistor ₈₁ → diode ₈₂ . Descharged and similarly commutated stopper diodes 2 to 4 and wheeling diode 10
There is no problem since the charge charged in the capacitor of each snubber circuit is descharged through each diode, but the problem is that the capacitor 9 which absorbs the surge on the power supply side is charged with the polarity shown. ₂ and a capacitor ₃₂ of the snubber circuit of the auxiliary thyristor 3.
As is clear from the illustrated circuit example, these capacitors 9 ₂ to 3 ₂ are constantly connected to the feed voltage of the feeder line.
If DC1500 (V) is used, approximately the same amount of charge is charged, and as is clear from the illustrated circuit example, there is no path for instantaneous discharge of these charges, such as a surge absorption capacitor on the power supply side. As is well known, ₉₂ has a large capacity, so the discharge time constant is large and it takes a considerable amount of time to discharge. Therefore, it is extremely dangerous to perform a predetermined inspection after turning on the discharge disconnector ₆₅ due to the undischarged charging voltage mentioned above.

The present invention was devised in view of this point, and will be described in detail below based on the embodiment shown in FIG.

Components in this embodiment that are the same as those in FIG. 1 are given the same reference numerals, and a particular feature of the present application is the insertion point of the discharge disconnector ₆₅ . That is, the device of the present application has a discharge disconnector 6 ₅ - like the conventional device shown in FIG.
The electric path of the discharge current suppressing resistor ₆₂ is not connected in parallel to the commutating capacitor 6, but is connected in parallel to the arm of the auxiliary thyristor 3, for example, as shown in the figure.

Next, to describe the operation of this embodiment, when a predetermined inspection of the thyristor circuit breaker is performed, first the discharge disconnector 6 is
Insert ₅ . When the disconnector ₆₅ is turned on in this way, the charge in the commutator capacitor 6, which is charged with the illustrated polarity, is transferred from the commutator capacitor 6 to the commutator reactor 5 to the stopper diode 4 to the disconnector ₆₅ .
The charge of the polarity _shown is descharged through the path of _the resistor ₆₂ and _is further charged to the snubber capacitor ₃₂ of the auxiliary thyristor.
→The charge that is discharged through the path of resistor ₃₁ and further charged to the surge absorption capacitor ₉₂ on the power supply side with the polarity shown is the capacitor ₉₂ → resistor ₉₁ → diode 2 → disconnector ₆₅ → resistor 6. It is discharged through the path of ₂ → resistor 8 ₁ → diode 8 ₂ . As is clear from this explanation of the operation, according to the present application, it is possible to connect the surge absorption capacitor on the power supply side and the snubber capacitor of the auxiliary thyristor, which was difficult with conventional devices, by simply changing the insertion point of the discharge disconnector. Charged charges can be instantly discharged.

As described above, in the present invention, the desired purpose can be achieved simply by changing the electrical path between the discharge disconnector for descharging the charge of the commutating capacitor and the discharge current suppressing resistor. It has various effects.

Since the charges in all capacitors are discharged at the time of a predetermined inspection, the predetermined inspection work can be performed with extremely high safety.

Since the desired purpose can be achieved without any additional equipment, a very economical thyristor circuit breaker can be provided.

Since the circuit configuration is relatively simple, a highly reliable thyristor breaker can be provided.

[Brief explanation of drawings]

FIG. 1 is a specific circuit configuration diagram showing a conventional thyristor breaker, and FIG. 2 is a specific circuit configuration diagram of a thyristor breaker showing an embodiment of the present invention. 1 is the main thyristor, 3 is the auxiliary thyristor, 3 ₂
is a snubber capacitor, 5 is a commutation reactor,
6 is a commutating capacitor, 6 ₅ is a discharge disconnector, 7 is a
Reactor for di/dt suppression, 9 ₂ is a capacitor for surge absorption on the power supply side.

Claims (1)

[Scope of utility model registration request] A main thyristor inserted into a DC circuit connecting a DC power source and a load to cut off the DC current, and a main thyristor installed between the cathode side of this main thyristor and the negative electrode of the DC power source to commutate the main thyristor. A first series circuit consisting of a commutating capacitor and a discharge prevention diode, and a snubber capacitor connected in parallel between the anode side of the discharge prevention diode of the first series circuit and the anode of the main thyristor. a second series circuit consisting of a first commutating stopper diode and an auxiliary thyristor; a cathode was connected to the anode side of the auxiliary thyristor, and the anode was connected to the cathode side of the main thyristor via a commutating reactor. A second commutation stopper diode, a discharge disconnector connected in parallel with the auxiliary thyristor and turned on during predetermined inspection work, and a discharge disconnector provided on the DC power supply side and the load side of the main thyristor and connected to the DC circuit. A thyristor circuit breaker comprising a surge absorption circuit for absorbing generated surges.