JPS628891B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic disconnector operating device for automatic operation of a power system.

When opening a disconnector, pay attention to the disconnection capacity of the disconnector. Generally, a disconnector has the ability to cut off the excitation current of a transformer and the charging current of a short line, but does not have the ability to cut off the load current. Therefore, the opening operation is performed after thoroughly checking that there is no load current in the disconnector and the connection state, for example, that no power source or load is connected to both ends of the disconnector. Conventionally, disconnector operation was performed manually or manually activated (even if it was electrically operated, it was activated manually), and was extremely slow because it involved human judgment and telephone contact with other substations. Therefore, there was no need to pay attention to current transient phenomena.

However, when automatic system operation is performed by an automatic system operation device such as an automatic restoration device, a series of operations are performed extremely quickly, so it has become necessary to pay attention to current transient phenomena.

This will be explained using the power system shown in FIG. 1 as an example.

In Figure 1, 1 to 3 bridges and disconnectors, 4 to 11
12 and 13 are power supply systems or generators, 14 is a load, 15 and 16 are cables, and 17 is a transformer.

Now, with the cable breaker 3 open and power being supplied from the power source 12 to the load 14, the cable 1
Assume that an accident occurs in No. 5, and the circuit breakers 1 and 2 are tripped by the protection relays. The load 14 immediately performs a series of system switching operations in order to receive power supply from the power system 13, but first, the disconnector 6 must be opened in order to disconnect the fault location from the system. Judging from the connection state, there is no fault current or current in the disconnector, so the conditions for opening the disconnector are met. However, for a while after the cable breakers 1 and 2 trip, the cables 15 and 1 appear as shown in Figure 2.
6, the zero-phase inductance 23a and resistor 23b of the transformer 17 (transformer zero-phase circuit), and the inductances 24a, 25a and resistors 24b, 2 of the cables 15, 16.
Due to the resonance phenomenon of 5b, damping transient currents i ₁ and i ₂ flow through the disconnectors 6 and 7, respectively. Depending on the system, these currents i ₁ and i ₂ greatly exceed the disconnection capacity of the disconnector. Therefore, the disconnector 6 cannot be opened immediately after the disconnector trips, and can only be opened after this transient current becomes sufficiently small. This transient current usually disappears in a few seconds to several tens of seconds, and this time varies depending on the individual system constants and connection conditions.
It can be estimated by calculation, experiment, etc. Therefore, it is possible to determine whether or not the disconnector can be opened based on the time that has passed since the disconnector was disconnected from the power source.

The present invention has been made in view of the above-mentioned points, and its purpose is to ensure that the magnitude of the above-mentioned transient current remains within the capacity of the disconnector, regardless of the opening/closing state of the disconnector in the event of an accident in the power system. To provide an automatic disconnector operating device which can open a disconnector after a period of time when the disconnector becomes lower than its breaking capacity, and which is not affected by transient current when opening the disconnector.

The present invention will be explained in detail below.

FIG. 3 shows an embodiment of the automatic disconnector operating device according to the present invention, and particularly shows the opening operation of the disconnector 6 in the system shown in FIG. 1 in the case described above.

If at least one of the disconnector 6, the disconnector 1, and the disconnectors 4 and 5 is open, and at least one of the disconnector 3, the disconnector 7, 10, and 11 is open, the opening operation is possible. It is a condition. Therefore, these conditions are detected by the detection circuit 31 shown in FIG. This detection circuit 31 is a circuit that determines whether the disconnector has been disconnected from the power supply system based on the open/close information of the associated disconnector or disconnector, and is also a condition detection circuit in accordance with the connection state of the disconnector in other systems. It is easy to make.

Now, in the detection circuit 31, the breaker 1, 3,
The opening/closing information of the disconnectors 4, 5, 7, 10, 11 is sent to the AND gate 31 through the OR gates 31a and 31b.
Enter c. If the AND condition is satisfied here, the above-mentioned condition for enabling disconnection of the disconnector 6 is satisfied, and an output is obtained from the AND gate 31c, that is, the detection circuit 31, but in this case, due to the presence of the above-mentioned transient current, a certain period of time elapses. Since the disconnector 6 cannot be opened until then, the timer circuit 33
The output of the disconnector 1 delayed by a certain time T may be used as the condition for enabling the disconnector 6 to be opened. Here, the settling time T of the timer circuit 32 may be set to the longest case in which the transient current in the system becomes below the disconnecting capacity of the disconnector.

Next, in the system shown in Figure 1, if only the breaker 1 is opened due to a busbar accident at substation A, and the breaker 2 remains closed, the cable charge will be discharged through the load, In this case, the shiya breaker 1,
Since the time constant of the transient current is shorter than when the disconnector 2 is opened, the disconnector 6 can be opened earlier. In this way, the time required for the disconnector to be opened and disconnected differs depending on the state of opening and closing of the disconnector. Therefore, in order to open the disconnector as quickly as possible, it is effective to change the setting time of the timer circuit according to each aspect of the open/close state of the disconnector.

An embodiment of the present invention applied to such a case is shown in FIG.

In FIG. 4, a portion 41 surrounded by a dashed line is used to detect that the disconnector is disconnected from the power supply system and to select the timer circuit setting time for the associated disconnector or disconnector connected to the disconnector. This is a detection circuit that performs detection from the open/closed state. In the detection circuit 41, disconnectors 1 to 3 and disconnectors 4, 5, and 7 are connected as shown in the figure.
-11 opening/closing information is input into OR gates 41a-41c, and AND gates 41d-41g perform an AND operation. The output terminals of AND gates 41d to 41g are connected to the input terminals of corresponding timer circuits 42 to 45, respectively, and the outputs of timer circuits 42 to 45 are configured to be outputted through OR gate 46. Here, each timer setting time of the timer circuits 42 to 45 is determined based on the associated disconnector connected to the disconnector, each aspect of the open/close state of the disconnector, that is, FIG.
They are set at T ₁ to _{T 4} corresponding to the open state of d. For example, the establishment of the AND of the AND gate 41d means the establishment of the open state shown in _FIG . Set the time to be below your capacity. Furthermore, since the establishment of the AND of the AND gate 41e means the establishment of the open state shown in FIG. 5b, the set time of the timer circuit 43 is
_T2 is set to a time during which the magnitude of the transient current in this open state becomes less than the disconnection capacity of the disconnector 6. Furthermore, since the establishment of the AND of the AND gate 41f means the establishment of the open state shown in _FIG . Set it to a time when the power is below the cutting capacity. Furthermore, since the establishment of the AND of the AND gate 41g means the establishment of the open state shown in FIG. 5d, the set time of the timer circuit 45 is
_T4 is set to a time during which the magnitude of the transient current in this open state becomes less than the disconnection capacity of the disconnector 6.

Accordingly, the corresponding timer circuit is activated by the output of the AND gate among the AND gates 41d to 41g for which an AND has been established, and the OR gate 46 is activated after the set time of the timer circuit corresponding to each aspect of the open state shown in FIGS. A signal indicating that the disconnector (in this case 6) can be opened is taken out through the disconnector. Note that in FIG. 5, the locations marked with an x mark are open.

In this way, the disconnector can be opened as quickly as possible without being affected by transient currents, depending on the opening/closing status of the related disconnectors and breakers connected to the disconnector to be opened. A condition fulfillment signal can be extracted, and the disconnector can be opened.

Furthermore, related disconnectors connected to the disconnector, and opening/closing information of the disconnecting switch can be easily obtained via a multipurpose data communication network, but if the opening/closing information cannot be obtained from the communication network, other Substation information cannot be used. Therefore, in this case, it is convenient to detect that the disconnector has been disconnected from the power supply system based on voltage information obtained from the voltage transformer installed in the own substation.

However, the power line voltage also does not immediately go to zero when disconnected from the power supply system, and transient phenomena exist.

Therefore, in the present invention, as shown in FIG. 6, the output obtained from the voltage transformer 63 provided at one end of the disconnector 61 is passed through a bandpass filter 64 for removing these transient phenomena. Monitor only commercial frequency components. That is, the output of the bandpass filter 64 is passed through the rectifier circuit 65 to obtain the DC level corresponding to the effective value, and this is compared with the set level from the constant voltage source 66 by the analog comparator 67, and the former is smaller than the latter. When the voltage at one end of the disconnector 61 becomes zero, it indicates that the voltage at one end of the disconnector 61 becomes zero, and the disconnector 6
This means that it has been detected that 1 has been disconnected from the power supply system. Then, the output of the comparator 67, that is, the output of the detection circuit 62, is supplied to the timer circuit 68 to operate the timer, and after the time has elapsed such that the magnitude of the transient current becomes equal to or less than the breaking force of the disconnector 61, the timer circuit 68 operates the disconnector 61. A signal indicating that the disconnector 61 can be opened is sent, and the disconnector 61 is opened. After the detection circuit 62 detects that the disconnector 61 has been disconnected from the power supply system, the timer circuit 6
Transient current can be taken into account by allowing the disconnector to be opened after the set time of 8 has elapsed. Note that the detection circuit 62 includes an instrument transformer 63, a bandpass filter 64, a rectifier circuit 65, a comparator 67, and the like.

Each of the embodiments of the present invention described above is a circuit that creates the conditions for opening the disconnector. As shown in FIG.
(Fig. 6) output of the disconnector automatic operating device 71 (signal indicating that the disconnector can be opened) and the system automatic operating device 7
The disconnector open operation command signal from 2 is sent to AND gate 7.
3, and when the AND is established, the disconnector opening operation output is sent out to perform the opening operation, it is possible to block the disconnector opening operation command when the disconnector opening operation is added.

Furthermore, if the system is configured as shown in FIG. 8, the disconnector open operation command from the system automatic operating device 72 is held in the R-S flip-flop 83, and the Even if the disconnector opening operation is temporarily blocked by the disconnector automatic operation device 71 and the AND gate 84 shown in FIG. However, in the R-S flip-flop 83, the disconnector open operation signal output from the AND gate 84 is connected to the reset terminal R via the OR gate 82.
When the output of the timer circuit 81 is input to the reset terminal R via the OR gate 82, the output of the timer circuit 81 is automatically reset after a certain period of time has elapsed after the disconnector open operation command is issued from the circuit 72. It's summery.

By combining as shown in FIGS. 7 and 8 in this manner, the disconnector can be opened only after the conditions for enabling the disconnector to be opened are established. In addition, each of the embodiments of the present invention described above (Figs. 3, 4, and 6)
A signal indicating whether or not the disconnector can be opened, which is an output from the automatic disconnector operating device shown in FIG.

As described above, the following effects can be obtained by using the present invention. In other words, (1) The timer circuit that operates based on the output of the detection circuit is set to the time when the disconnector current becomes below the disconnection capacity of the disconnector.
A disconnector inserted in a power system can be opened quickly without being affected by transient current.

(2) The disconnector is in a state where it should be released based on the opening/closing information of the related disconnector connected to the disconnector (it is disconnected from the power system)
It is possible to detect whether the Moreover, since the command signal for opening the disconnector can be sent after the time set in the timer circuit has elapsed after detecting that the disconnector should be opened, the disconnector can be opened quickly without being affected by transient currents. Can be opened.

(3) Since the detection circuit is designed to detect that the disconnector is disconnected from the power supply system when the voltage at one end of the disconnector becomes zero, it is possible to detect whether the disconnector is connected to the disconnector that is about to be opened. Even if opening/closing information cannot be obtained from a substation-related disconnector or disconnector, it is possible to easily detect that the disconnector has been disconnected from the power supply system. Furthermore, even in this case, the disconnector can be opened quickly without being affected by transient current.

(4) A detection circuit is provided for each mode of the open/closed state of the related disconnector connected to the disconnector, and a timer circuit is provided for each of the detection circuits for each of the above-mentioned modes, Moreover, the set time of the timer circuit is set according to each of the above-mentioned aspects. Therefore, in the event of an accident in the power system, it is possible to determine whether or not the disconnector should be opened, regardless of the opening/closing state of the associated disconnector or shield disconnector connected to the disconnector. In addition, no matter what mode the related disconnector or circuit breaker is in the open/close state when the detection circuit detects that it should be opened, the time most suitable for the mode (timer circuit setting time) (i.e., the time period during which the transient current flowing through the disconnector becomes less than the cutting capacity of the disconnector), a signal indicating that the disconnector can be opened can be sent. This allows the disconnector to be opened quickly without being affected by transient currents, regardless of the opening/closing state of the associated disconnector or shield disconnector connected to the disconnector.

(5) When automatic system operation is performed using an automatic system operation device such as an automatic restoration device, a series of operations are performed extremely quickly. The opening operation can be fully handled without being affected by current transient phenomena.

[Brief explanation of the drawing]

FIG. 1 is a power system diagram for explaining the present invention,
FIG. 2 is an equivalent circuit diagram showing the cable charge discharge circuit when the disconnectors 1, 2, and 3 are open in FIG. 1, and FIG. 3 is an embodiment of the disconnector automatic operating device according to the present invention. 4 is a circuit diagram showing another embodiment of the automatic disconnector operating device according to the present invention, and FIGS. 5 a to d are the power system of FIG. 1 used to explain FIG. 4. FIG. 6 is a circuit diagram showing another embodiment of the present invention, and FIGS. 7 and 8 each show an application example to which the present invention is applied. In the diagram, 1 to 3 are disconnectors, 4 to 11 are disconnectors, 12 and 13 are power supply systems or generators, and 1 to 3 are disconnectors.
5, 16 are cables, 17 is a transformer, 31, 4
1 and 62 are detection circuits, 32, 42 to 45, and 68 are timer circuits, and 46 is an OR gate.

Claims (1)

[Scope of Claims] 1. When opening a disconnector inserted in a power system, a detection circuit detects that the disconnector is disconnected from the power supply system, and an operation is performed based on the detection output of this detection circuit. and a timer circuit that sends a signal to enable opening of the disconnector after a predetermined time,
An automatic disconnector operating device, characterized in that the predetermined time of the timer circuit is set to a time when the current of the disconnector becomes equal to or less than the breaking capacity of the disconnector. 2. The automatic disconnector operation according to claim 1, wherein the detection circuit detects that the disconnector has been disconnected from the power supply system based on the opening/closing information of the related disconnector connected to the disconnector. Device. 3. The automatic disconnector operating device according to claim 1, wherein the detection circuit detects that the disconnector is disconnected from the power supply system when the voltage at one end of the disconnector becomes zero. 4. A detection circuit is provided for each mode of the opening/closing state of the related disconnector connected to the disconnector, and a timer circuit is provided corresponding to the detection circuit for each mode. The invention operates based on the detection output of the detection circuit for each mode, and sends out a signal enabling the disconnector to be opened after each predetermined time, and each of the predetermined times is set depending on the mode. The disconnector automatic operating device according to item 2.