JPH07298478A - Circuit breaker control method - Google Patents

Abstract

(57) [Summary] [Object] The present invention provides a control method of a circuit breaker that suppresses the occurrence of overvoltage when a transmission line is opened during a transmission line accident. [Structure] The present invention relates to a circuit breaker control method for controlling circuit breakers installed at both ends of a power transmission line by protective relays.
In parallel with the main circuit breaker of each phase at both ends of the power transmission line, a circuit breaker with a resistor is connected, and the protective relay sends an open command signal to the main circuit breaker under the condition that the power transmission line is in a single-phase open phase. When output, the main circuit breaker of the phase to which the circuit breaker opening command signal is output is first opened, and then the circuit breaker with resistance connected in parallel with this opened main circuit breaker is opened. Therefore, by absorbing the vibration energy by the resistance, it is possible to control the generation of the overvoltage due to the LC free vibration that occurs when the transmission line is out of phase thereafter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breaker control system in which circuit breakers at both ends of a transmission line are opened by an operation signal of a protective relay.

[0002]

2. Description of the Related Art FIG. 11 shows a simplified power system configuration centered on general transmission line protection, particularly a system configuration of a circuit breaker control system. In the figure, a phasing capacitor 6 and a transformer 9 are connected to a power supply 12 via a power transmission line 1. Circuit breakers 2a and 2b are installed at both ends of the power transmission line 1 between each phase and the busbars 5a and 5b. This circuit breaker 2
A protective relay 4 such as an overcurrent relay or a current differential relay is provided for each phase of the transmission line in order to open and close a and 2b in the case of a transmission line accident, and protective relays 13a and 13b such as an undervoltage relay and an overvoltage relay are provided. Is the bus 5 to which the power transmission line connects
It is installed in each phase a, 5b. When an accident such as a short circuit or a ground fault occurs on the power transmission line 1, the protective relays 4a, 4
b, the accident is detected by the protective relays 13a, 13b, and an opening command is given to the circuit breakers 2a, 2b at both ends of the transmission line 1 of the phase in which the accident has occurred.

[0003]

By the way, in the prior art, when a single-phase accident occurs in the transmission line and the circuit breakers at both ends of the transmission line in the accident phase are opened to enter the single-phase open phase state, a high resistance grounding system is provided. Alternatively, in the case of a non-grounded system, an overvoltage is generated on the bus bar due to LC free vibration of a reactor component such as a load side and a capacitor component such as a phasing capacitor. For example,
In the case where both L and C are ungrounded Y connection on the load side as shown in FIG. 12, if voltage V is applied across each capacitor, E =
(1/2) ・ C ・ V ² becomes vibration energy,

[Equation 1] An oscillating current flows through the circuit.

This vibrating circuit is shown in FIG.

[Equation 2] An oscillating current flows at the vibration frequency of. An overvoltage is generated by superposing the vibration frequency component and the fundamental wave component. The magnitude of the overvoltage depends on the voltage applied to each capacitor when the switch shown in FIG. 12 is opened, and is twice as large as that when the LC element is three-phase balanced, and as large as before when the LC element is unbalanced. 4 ~
There is a problem that an overvoltage of 5 times is generated.

The present invention has been made to solve the above problems, and an object thereof is to provide a control system for a circuit breaker that suppresses the occurrence of overvoltage when the transmission line is opened even in the case of a transmission line accident. .

[0006]

In order to solve the above-mentioned problems, claim 1 of the present invention relates to a circuit breaker control system for controlling circuit breakers installed at both ends of a power transmission line by protective relays. A circuit breaker with a resistor is connected in parallel to the main circuit breaker of each phase at both ends of the power transmission line, and the protection relay outputs an open command signal to the main circuit breaker under the condition that the power transmission line has a single phase open phase. Then, the main circuit breaker of the phase to which the command signal for opening the circuit breaker is output is opened first, and then the circuit breaker with resistance connected in parallel with the opened main circuit breaker is opened. And

According to a second aspect of the present invention, there is provided a circuit breaker control system for controlling circuit breakers installed at both ends of a power transmission line by protective relays, wherein a main circuit breaker of each phase at both ends of the power transmission line is provided in parallel with a resistor. When a circuit breaker is connected and the protection relay outputs an opening command signal to the circuit breaker under the condition that the transmission line is in a single-phase open phase, first the main circuit breaker of the phase to which the circuit breaker opening command signal is output. Is opened and then the circuit breaker with resistance is opened on condition that the operation signal of the overvoltage relay is not output for a certain period of time.

According to a third aspect of the present invention, there is provided a circuit breaker control method for controlling circuit breakers installed at both ends of a power transmission line by protective relays, wherein the protective relay is a single-phase open phase with respect to the circuit breaker. Under this condition, when the command signal to open the circuit breaker is output, the circuit breaker on the power supply side of the circuit breakers at both ends of the transmission line for which the command signal to open the circuit breaker is output is opened first, and then the other load side is disconnected. It is characterized by releasing the vessel.

According to a fourth aspect of the present invention, in a circuit breaker control system in which circuit breakers installed at both ends of a power transmission line are controlled by protective relays, the protective relay causes the circuit breaker to have a single-phase open phase. When the command signal to open the circuit breaker is output under the following conditions, first the circuit breaker on the power supply side is opened first among the circuit breaker at both ends of the transmission line where the command signal to open the circuit breaker is output. Is delayed by a predetermined time, and then the load side circuit breaker is released.

[0010]

According to the present invention (corresponding to claims 1 and 2), immediately after the occurrence of a single-phase open phase accident, the main circuit breaker is opened to cause a fault current to flow through the circuit breaker with resistance, and damping is used to vibrate by the resistance. By absorbing the energy, it is possible to control the generation of an overvoltage due to the LC free vibration that occurs when the transmission line is out of phase thereafter.

According to the present invention (corresponding to claims 3 and 4), immediately after the occurrence of a single-phase open phase accident, the circuit breaker on the power source side is opened first, and the breaker on the load side is opened later. Reduces the voltage applied to the capacitor when in phase,
As a result, the vibration energy of the LC free vibration is reduced to reduce the vibration voltage on the load side and control the generation of overvoltage.

[0012]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a system configuration diagram of a first embodiment (corresponding to claim 1) of the present invention. In the figure, circuit breakers with resistors (circuit breakers connected in series with resistors) 3a, 3b are connected in parallel to the phase breakers 2a, 2b at both ends of the transmission line 1. Protective relays 4a and 4b, protective relay 13a, and busbars 5a and 5b and transmission line 1
13b is provided, and a sequence for determining an open phase accident is provided by a combination of operation signals of this relay group. Relay 4
When a, 4b, 13a, 13b outputs a command signal for circuit breaker opening, if the accident is an open phase accident, the main circuit breakers 2a, 2b for which the command signal is output are opened, and this command signal is time delayed. The signal is input to the set delay 8 and the circuit breaker with resistor 3 is opened by the output signal from the delay 8. Relay 4
When a, 4b, 13a, 13b output a command signal to open the circuit breaker under conditions other than an open phase accident, the main circuit breakers 2a and 2b to which the command signal is output and a resistor installed in parallel with the circuit breaker The circuit breakers 3a and 3b are simultaneously opened.

The above sequence consists of a main circuit breaker opening sequence and a resistance circuit breaker opening sequence, and is shown in FIG. This sequence is provided for each circuit breaker (main circuit breaker and circuit breaker with resistor are one set).

In this embodiment, in the case of a single-phase open phase accident in a transmission line,
For example, if there is a one-phase ground fault in the case of a single-line power transmission line, or if there is a two-line power line in the same phase of a two-line transmission line, a command signal to open the breaker from the protective relay and The main circuit breakers 2a and 2b are opened by a signal indicating a phase accident. The circuit breakers with resistors 3a and 3b are opened after a fixed time set by the output signal from the delay 8 using the command signal as an input signal. With this operation, when a single-phase open phase accident occurs, a current is passed through the resistor to start the accident elimination, and damping is used.
After that, the circuit breaker with resistance is opened to suppress the overvoltage. The main circuit breaker and the circuit breaker with a resistor installed in parallel with the circuit breaker are opened at the same time except during a single-phase open phase accident.

As described above, after the main circuit breaker is opened at the time of a single-phase open phase accident in the power transmission line, and the fault current is passed through the resistors connected in parallel to the circuit breaker, the circuit breaker with resistance is opened. Overvoltage can be suppressed.

FIG. 3 is a system configuration diagram of a second embodiment (corresponding to claim 2) of the present invention. In the figure, the circuit breakers with resistors 3a, 3 are connected in parallel to the circuit breakers 2a, 2b at both ends of the transmission line 1.
Connect b. The busbars 5a, 5b and the power transmission line 1 are provided with protective relays 4a, 4b, 13a, 13b, and a sequence for determining an open phase accident is provided by a combination of operation signals of the relay groups. When the relays 4a, 4b, 13a, 13b output the command signal for opening the circuit breaker, if the accident is a phase failure, the main circuit breaker for which the command signal is output is opened, and then the operation of the overvoltage relays 13a, 13b. When the signal is not output for a certain period of time, that is, when the output signal of the on-delay 11 in FIG. 4 is output, the circuit breakers with resistors 3a and 3b installed in parallel with the circuit breaker are opened. Relays 4a, 4
b, 13a, 13b outputs a command signal for opening the circuit breaker under conditions other than the open phase accident, the main circuit breakers 2a, 2b to which the command signal is output, and a resistor installed in parallel with the circuit breaker. The circuit breakers 3a and 3b are opened.

The above sequence consists of a main circuit breaker opening sequence and a resistance circuit breaker opening sequence, and is shown in FIG. In each of the embodiments, the main circuit breaker is normally closed and the circuit breaker with resistance is opened, and the circuit breaker with resistance is closed when the main circuit breaker is opened under the single-phase open phase eventual condition. The circuit breaker with resistance may be opened.

FIG. 5 is a system configuration diagram of a third embodiment (corresponding to claim 3) of the present invention. As shown in FIG.
a, 5b, the transmission line 1 has protective relays 4a, 4b, 13
a and 13b are provided, and a sequence for determining an open phase accident is provided by combining the operation signals of the relay groups. When the relays 4a, 4b, 13a, 13b output the command signal for opening the circuit breaker, if the accident is a phase failure, the circuit breaker 2a on the power supply side is opened. When the contact signal of the circuit breaker 2a is turned off and the relays 4a, 4b, 13a, 13b output a command signal for opening the load side circuit breaker 2b, the load side circuit breaker 2b is opened. The above sequence consists of the power supply side and the load side, and is shown in FIG.

According to this embodiment, at the time of a single-phase open phase accident in the transmission line, the breaker on the power supply side is opened by the command signal for opening the breaker from the protective relay and the signal indicating the open phase accident. The load side circuit breaker is opened when the contact signal of the circuit breaker is turned off and the load side circuit breaker opening command signal is output.

Therefore, in this embodiment, in the case of a single-phase open-phase accident in the transmission line, the circuit breaker on the power supply side is opened first and the circuit breaker on the load side is opened later to suppress the overvoltage after the circuit breaker is opened. can do. The reason will be described below. Here, when the load side circuit breaker is opened, the vibration energy is compared when the power source side circuit breaker is opened first and when it is closed. Since the vibration energy is determined by the voltage applied to each capacitor when the breaker is opened, this voltage is indicated by a vector.

First, in the case where the power source side circuit breaker is closed, in the case of the ungrounded Y connection of FIG. 12, the sound phase voltage is as shown in FIG.
Is the dotted line, and the voltage across each capacitor is like the solid line. If vibration energy E is ungrounded Y-connection _{E = (1/2) C R ·} V ON 2 + (1/2) C S · V SN 2 + (1/2)
Since it is determined by C _T · V _TN ² , in this case V _ON = cos θ V _SN = cos (θ−120 °) V _TN = cos (θ + 120 °) C _R = C _S = C _T = C to E1 = (3 / 4) ・ It becomes C.

On the other hand, when the circuit breaker on the power source side is opened first, the voltage applied to each capacitor when the impedance on the system side is small becomes the solid line in FIG. When the vibration energy E2 in this case is similarly obtained, E2 = (3/4) · C · sin ² θ. Here, considering that the current is cut off at the zero point, θ = 0 ° or θ = 180 °, so E2 = 0.

Even when the system side impedance is large, E2 is about 1/6. In this way, by opening the breaker on the power supply side first, it is possible to suppress overvoltage due to vibration energy.

FIG. 7 is a system configuration diagram of the fourth embodiment (corresponding to claim 4) of the present invention. The protective relay outputs a command signal to open the circuit breaker at the time of an accident and a signal indicating whether or not there is an open phase accident. In the case of an open phase accident, the circuit breaker on the power supply side is opened first among the circuit breakers for which the command signal to open the circuit breaker appears, and the command signal to open the circuit breaker is delayed by delay 8, and the output signal of the circuit breaker opens. Open the circuit breaker. The above sequence consists of the power source side and the load side, and this sequence is shown in FIG.

[0025]

As described above, according to the present invention, the circuit breaker suppressing method for suppressing the LC oscillating current at the time of a single-phase open-phase accident has been implemented. The effect that can suppress is obtained.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a first embodiment of the present invention.

FIG. 2 is a diagram showing a sequence of control methods for the circuit breaker of FIG.

FIG. 3 is a system configuration diagram of a second embodiment of the present invention.

4 is a diagram showing a sequence of control methods for the circuit breaker of FIG.

FIG. 5 is a system configuration diagram of a third embodiment of the present invention.

6 is a diagram showing a sequence of the control method of FIG.

FIG. 7 is a system configuration diagram of a fourth embodiment of the present invention.

8 is a diagram showing a sequence of control methods for the circuit breaker of FIG.

FIG. 9 is a voltage vector diagram when an R-phase ground fault power source side circuit breaker is closed.

FIG. 10 is a voltage vector diagram when the R-phase ground fault power source side circuit breaker is opened.

FIG. 11 is a system configuration diagram of a conventional circuit breaker control system.

FIG. 12 is a circuit diagram of a load side ungrounded Y connection.

13 is an equivalent circuit diagram of the vibration circuit of FIG.

[Explanation of symbols]

1 ... Transmission line, 2a, 2b ... Main circuit breaker, 3a, 3b ... Resistor circuit breaker, 4a, 4b ... Protective relay, 5a, 5b ... Bus bar, 6 ... Capacitor, 7 ... Inductor, 8 ... Delay,
9 ... Transformer breaker, 10 ... Filter SC breaker, 1
1 ... On-delay, 12 ... Power supply, 13a, 13b ... Protective relay.

Claims (4)

[Claims] 1. In a circuit breaker control method for controlling circuit breakers installed at both ends of a power transmission line by protective relays, a circuit breaker with a resistor is provided in parallel with a main circuit breaker of each phase at both ends of the power transmission line. When connected and the protection relay outputs an open command signal to the main circuit breaker under the condition that the transmission line is in single-phase open phase, first open the main circuit breaker of the phase to which the circuit breaker open command signal is output. The circuit breaker control method is characterized in that the circuit breaker with a resistor connected in parallel with the opened main circuit breaker is then opened. 2. A circuit breaker control method for controlling circuit breakers installed at both ends of a power transmission line by protective relays, wherein a circuit breaker with a resistor is provided in parallel with a main circuit breaker of each phase at both ends of the power transmission line. When connected, the protective relay outputs an open command signal to the circuit breaker under the condition that the transmission line is in single-phase open phase,
First, the main circuit breaker of the phase to which the circuit breaker opening command signal is output is opened, and then the circuit breaker with resistance is opened on condition that the operation signal of the overvoltage relay is not output for a certain period of time. Control system for circuit breaker. 3. A circuit breaker control method for controlling circuit breakers installed at both ends of a power transmission line with protective relays, under the condition that the protective relay is a single phase open phase with respect to the circuit breaker. When the circuit breaker open command signal is output, the circuit breaker on the power supply side of the circuit breaker at both ends of the transmission line where the circuit breaker open command signal is output is opened first, and then the circuit breaker on the other load side is released. A circuit breaker control method characterized by: 4. A circuit breaker control method for controlling circuit breakers installed at both ends of a power transmission line by protective relays, under the condition that the protective relay is a single-phase open phase with respect to the circuit breaker. When the command signal to open the circuit breaker is output, first the circuit breaker on the power supply side is opened first among the circuit breaker at both ends of the transmission line where the command signal to open the circuit breaker is output, and this command signal to open the circuit breaker is delayed. A circuit breaker control method, characterized in that the circuit breaker on the load side is released after a delay of a predetermined time.