JPH03135334A - Circuit breaker control apparatus for phase modifying equipment - Google Patents

Abstract

PURPOSE:To execute a cutoff operation without generating a reignition by outputting a pullout command at an appropriate time point calculated on the basis of the detected value of an AC current at a zero phase point, the contact parting time and the arc time of a circuit breaker and the operating time of an electric circuit. CONSTITUTION:A sampling processing is executed via a sampling circuit 53, where whether a circuit breaker pullout command is present is judged. When the pullout command is present, sampling data are read and a phase zero point and a frequency are detected. Then, a time Ttr is calculated. When the time Ttr is obtained, whether the present time point is a command time point is judged by comparing with the time Ttr. When the present time point is the command time point, whether a target circuit breaker 3 is in a closed condition is judged. Thus, by outputting the pullout command so as to conduct a contact parting at an appropriate phase point, a circuit breaker operation can be executed without generating a reignition.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention is a circuit breaker control device for phase adjusting equipment, particularly for controlling the opening phase of a current to be cut off in order to prevent re-ignition. The present invention relates to a breaker control device for phase modifier equipment.

(Prior art) In order to adjust reactive power in a power system, a shunt reactor for offsetting leading power in the grid and a shunt capacitor for offsetting lag power in the grid are connected to the grid via a breaker. Connecting is widely practiced.

Figure 4 shows an example of such a system configuration.
A shunt reactor 2 for flowing delayed power for phase adjustment is connected to the power system 1 via a breaker 3. The shunt reactor 2 is shown as an example, and generally a shunt capacitor is also provided via suitable switching means so that forward power can also flow. In such phase adjustment equipment, when the breaker 3 switches on and off the lagging current or the leading current, for example, when the lag current flowing in the shunt reactor 2 is cut off by the breaker 3, the voltage of the power system 1 is changed as shown in Fig. 5. As shown by V and current i, if the arc time (time from opening until current i reaches zero) is short when the current is cut off, re-ignition will almost always occur, and this will occur at that time. There is a problem in that the excessive surge voltage puts stress on the insulating parts of the breaker connection gap switch and the shunt reactor 2, accelerating the deterioration of those parts.

(Problems to be Solved by the Invention) If the dielectric strength between the breaker electrodes cannot withstand the voltage between the electrodes when the circuit breaker is opened, it will re-ignite. FIG. 5 shows an example where such re-ignition occurs.

The surge voltage generated by the re-ignition is affected by the capacitance and inductance of the lines and equipment on the load side and power supply side of the breaker.

The present invention has been made to solve the above problems, and is a breaker control device for phase adjustment equipment that controls the opening of the breaker so that re-ignition does not occur when the reactive power device for phase adjustment is opened. is intended to provide.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the breaker control device for phase adjustment equipment of the present invention includes a detection means for detecting an amount of alternating current electricity in a power system, and a calculation means for calculating the phase zero point and frequency of the amount of alternating current electricity detected by the means; setting means for setting the opening time and arcing time of the breaker; and the operating time of the electric circuit; and a detection means for detecting the breaker control voltage. a calculation means for calculating a correction value for the operation time of the circuit breaker using the detection means; and a tripping unit for outputting a tripping command based on the phase zero point calculated by the calculation means and each time set by the setting means. It is characterized by comprising a command means.

(Function) Re-ignition, which is calculated based on the detected value, the opening time of the circuit breaker, the arcing time, and the operating time of the electric circuit, by detecting the phase zero point of the alternating current electricity in the power system, such as the phase zero point of the alternating current. By issuing a tripping command at an appropriate timing that does not cause a tripping command, an ideal breaker operation that does not cause re-ignition can be performed, thereby preventing excessive surges and Prevent insulation deterioration of equipment.

(Example) Examples will be described below with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of a breaker control device for phase modifier equipment according to the present invention.

In FIG. 1, a breaker control device 5 for phase adjustment equipment controls a current i in order to use a breaker 3 to interrupt a current i flowing in a shunt reactor 2 connected to a power system 1 via a breaker 3. This device detects the current with the current detector 4 and sends a tripping command to the breaker 3 at an appropriate phase point. The output signal of current detector 4 is led to input converter 51. The input converter PAa 51 converts the current signal from the current detector 4 to a level suitable for signal processing.

The output signal of the input converter 51 is passed through a filter (Fll, ) 5
2, the signal is sampled at every sampling period ΔT by a sampling circuit (SH) 53 which generates a hold circuit. The sampled value by this sampling circuit 53 and the breaker control voltage value inputted via the voltage divider 62 are sent to a multiplexer<HPX
) 54 in a time-series manner and input to the ^/D converter 55, where it is converted into a digital quantity.

This digital quantity is stored by OP RAM 56. Digital quantities stored in the OP RAM 56 are transferred to the central processing unit W, (CPU) 5 via a bus 57.
8, the data is processed. CPo 58 includes a digital input circuit (D/I) for externally inputting a breaker disconnection command via bus 57 59. L or disconnector 3
A digital output circuit (D
lo) 60, and a setting circuit 61 for setting the opening time T1 of the circuit breaker 3, are connected to the circuit breaker 3, respectively.

Here, the instantaneous value of the current i read at the sampling time t is defined as ill, and the value of the current read at the next sampling time t1141 after the sampling period ΔT has elapsed is i.
Then, if the vicinity of the zero point of the sine wave 1N+1 in Fig. 2(b) is approximated by a right-angled triangle as shown in Fig. 2(C), then the following equation is obtained, where the time from the current zero point to the point +1 is set as X. Stand up.

i : i = (ΔT-x): x re n++1 X = ΔT-i / (i + i ) −・(
1) m+1 rln+1 The time X obtained here is the sampling time t141
This means that time X has passed since the zero point.

Further, since the optimum calculation result of the trip command time changes depending on the frequency fluctuation, the frequency is determined from the current zero point determined from the sampling value, and the averaged frequency f is calculated.

Next, as shown in Fig. 2(a), if the target arc time is 1', the opening time of the shear breaker 3 is CT1, and the operating time of the control circuit that issues the tripping command is tl, then Based on the time of zero point detection, then the next time ′
It is only necessary to send a control signal to issue a tripping command to the control circuit at time ttr, when time rtr has elapsed.

Furthermore, since the opening time of the breaker varies depending on the control voltage variation, the voltage variation correction time 'rk is determined from the control voltage (■).

Tk=k(■.-V) k: Voltage correction coefficient + Vo: Rated voltage T = (1
/f ) + + (1/2f) -TaC1r T t x Th 1 (3/2f) T T-tlx xac
1...(2) Each of the above calculations is executed by the CPo 58.

Next, the operation of the control device will be explained with reference to the flowchart shown in FIG.

It starts by turning on the power to the control device, and first,
Initialization processing is performed (step 51) 0
Next, sampling processing is performed via the sampling circuit 53 (step S2), and it is then determined whether there is a breaker disconnection command (step S3). If there is no tripping command (eaves 'N''), the sampling process is performed again. If there is a tripping command in step S3 (Y')
Reading of sampling data is performed (step S4), and phase zero point detection and first frequency detection are performed (step S5). Next, time T according to equations (1) and (2)
tr is calculated (step S6).

Once the time T is determined, it is determined whether the current time is the command time by comparing it with the time Ttrt (
Step S7). If it is not the command time (N'°), the tripping command is not sent out. If it is the command time, it is determined whether or not the target breaker 3 is in the on state (step S8), and if it is not in the on state ("N"), the process returns to the sampling state in step S2. The above-described tripping control is performed for each breaker of each phase.

As described above, since the zero point of the current phase is detected and a tripping command is issued so that the contact is opened at an appropriate phase point, the breaking operation can be performed without causing re-ignition.

Although the embodiments described above have been described in terms of cutting off the current flowing through the shunt reactor, the present invention is also applicable to the case where a power capacitor provided for phase advancement is cut off.

[Effects of the Invention] As explained above, according to the present invention, a trip command is issued in consideration of the detected current zero point and the opening time of the target breaker, and an ideal trip command that does not cause re-ignition is generated. A shutoff operation can be performed.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an embodiment of a breaker control device for phase adjustment equipment according to the present invention, FIG. 2 is a waveform diagram for setting the current cutoff time, and FIG. 3 is a flowchart showing the processing contents of the control device. FIG. 4 is a diagram showing an example of connecting a reactor for adjusting reactive power, and FIG. 5 is a diagram showing the relationship between current interruption by a circuit breaker and surge voltage. 5... Breaker control device for phase modifier equipment 51... Input converter 52... Filter 5
3... Sample hold circuit 54... Multiplexer 55... A/D conversion circuit 56... DP RAM 57... Bus 58... CPU 59... D/1
60... Dlo 61... Setting circuit 62... Voltage divider

Claims (1)

[Claims] Means for detecting the amount of alternating current electricity in the power system, calculation means for calculating the phase zero point and grid frequency of the amount of alternating current electricity detected by the detection means, the opening time and arcing time of the breaker, and the operating time of the electric circuit. Set the setting time and
a calculation means for correcting the opening time in consideration of control voltage fluctuations of the circuit breaker; and a tripping device for outputting a trip command based on the phase zero point calculated by the calculation means and each time set by the setting means. 1. A breaker control device for phase adjustment equipment, characterized by comprising a command means.