Protection and control device and protection and control system

Abstract

To provide a protective control device and a protection control system capable of reliably interrupting lines that need to be simultaneously interrupted.SOLUTION: A protective control device includes a voltage acquisition unit, an abnormality detection unit, a control condition setting unit, a group decomposition unit, and an output unit. The voltage acquisition unit acquires a voltage of a power system. The abnormality detection unit detects a frequency abnormality when a time period during which a frequency of the acquired voltage is equal to or less than a setting value is equal to or longer than a predetermined time. The control condition setting unit sets, on the basis of the detected frequency abnormality, control conditions for each of a plurality of line groups including a plurality of lines which are set in advance. The group decomposition unit distributes a control signal to be provided for the plurality of lines included in the line group, when the control conditions are satisfied. The output unit outputs the control signal to the plurality of lines.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a protection control device and a protection control system. [Background technology]

[0002] Under-frequency relay (hereinafter referred to as UFR) devices are used as protection and control devices in power systems, for example, as devices to counter under-frequency (see, for example, Non-Patent Document 1). Under-frequency phenomena in power systems occur when the supply (power source) is less than the demand within the power system, due to, for example, a power source tripping or system separation. By installing multiple UFR devices within the power system and cutting off predetermined loads when the frequency drops, it is possible to maintain the supply and demand balance within the power system and restore the frequency to its original state.

[0003] FIG. 1 is a diagram illustrating an example of a conventional UFR device 100. The conventional UFR device 100 includes, for example, a voltage acquisition unit 110, an abnormality detection unit 120, and an output unit 130. The UFR device 100 is connected to a voltage detection unit 200 that detects the voltage of the power system and a circuit breaker 300 that breaks the load. The circuit breaker 100 is connected to the circuit breaker 300 via, for example, an electric cable. For example, when the power system includes a first line to an n-th line (n: an integer equal to or greater than 1), the UFR device 100 causes the circuit breaker 300 to break the load on each of the lines.

[0004] The voltage acquisition unit 110 acquires the voltage of the power system detected by the voltage detection unit 200. The abnormality detection unit 120 includes, for example, a frequency abnormality detection unit 121 and a timer unit 122. The frequency abnormality detection unit 121 measures the frequency of the power system based on the power system voltage acquired by the voltage acquisition unit 110, and determines whether a frequency abnormality state has occurred in which the frequency has dropped below a predetermined level of cutoff target value (hereinafter referred to as a set value). The frequency abnormality detection unit 121 includes a first UFR 121-1 to an n-th UFR 121-n. The frequency abnormality detection unit 121 determines whether a frequency abnormality state of a cutoff level set for each line has occurred.

[0005] The timer unit 122 measures the duration of a frequency anomaly state. The timer unit 122 has set therein first timer time 122-1 to n-th timer time 122-n, which are timer times for each line. The timer unit 122 is activated when the frequency anomaly detection unit 121 detects a frequency anomaly, measures the duration of the frequency anomaly state for each line, and determines whether the duration of the frequency anomaly exceeds the timer time.

[0006] When the duration of the frequency anomaly measured by the timer unit 122 exceeds a predetermined timer value, the output unit 130 outputs a control command to the circuit breaker 300 to shed the load. When the power system includes the first circuit to the nth circuit, the output unit 130 includes the first output unit 130-1 to the nth output unit 130-n. The first output unit 130-1 to the nth output unit 130-n output control commands to shed the loads of the first circuit to the nth circuit of the power system, respectively. The UFR device sheds the load for each circuit.

[0007] To shed the load for each line, the anomaly detection unit 120 detects frequency anomalies for the first UFR to the nth UFR. The timer unit 122 measures the duration of the frequency anomaly for each of the first UFR to the nth UFR. For lines that require simultaneous closure, simultaneous closure is achieved by, for example, setting the setting value of the frequency anomaly detection unit and the timer value of the timer unit to the same value.

[0008] Furthermore, renewable energy sources are now often connected to circuits, and UFR devices are sometimes designed to look at the direction of the current and cut off only the circuits that act as a load. However, if a renewable energy generator is connected midway through the first circuit 1L or the second circuit 2L, the current values ​​of the first circuit 1L and the second circuit 2L may differ, with one in the load direction and the other in the power generation direction. For this reason, it is necessary to determine the current direction based on the current flow of both circuits combined.

[0009] Furthermore, when collecting the power flow values ​​of each line of multiple UFR devices in one place and determining the control priority (shutdown priority) that indicates the priority of shutdown, if it is necessary to shut down lines of different UFR devices simultaneously, those lines must be treated as a single load.

[0010] In the conventional UFR device 100, the setting value of the frequency anomaly detection unit 230 and the timer value of the timer unit are set for each line, so the setting value and timer value are set to be the same for lines that need to be cut off at the same time. However, for example, when changing the setting value, there is a possibility that different setting values ​​may be mistakenly set for lines that need to be cut off at the same time, in which case the lines that need to be cut off at the same time cannot be cut off at the same time. [Prior art documents] [Non-patent literature]

[0011] [Non-Patent Document 1] Akihiko Yokoyama and Koji Ota, "Power System Stabilization System Engineering," Institute of Electrical Engineers of Japan, 2014 Summary of the Invention [Problem to be solved by the invention]

[0012] The problem to be solved by the present invention is to provide a protection control device and a protection control system that can reliably and simultaneously cut off circuits that need to be cut off simultaneously. [Means for solving the problem]

[0013] A protection and control device according to an embodiment includes a voltage acquisition unit, an abnormality detection unit, a control condition setting unit, a group decomposition unit, and an output unit. The voltage acquisition unit acquires the voltage of a power system. The abnormality detection unit detects a frequency abnormality when the frequency of the acquired voltage remains below a set value for a predetermined period of time or longer. The control condition setting unit sets control conditions for each of a plurality of line groups, each of which includes a predetermined number of lines, based on the detected frequency abnormality. The group decomposition unit distributes a control signal to be provided to a plurality of lines included in the line group when the control condition is satisfied. The output unit outputs the control signal to a plurality of lines. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram showing an example of a conventional UFR device 100. [Figure 2] FIG. 1 is a diagram showing an example of a UFR device 1 according to a first embodiment. [Figure 3] FIG. 10 is a diagram showing an example of a line group reference table. [Figure 4] FIG. 10 is a diagram showing an example of a line reference table. [Figure 5] FIG. 10 is a diagram showing an example of grouping multiple circuits within the same power station. [Figure 6] FIG. 10 is a diagram showing an example of grouping a plurality of lines between a plurality of electric power stations. [Figure 7] FIG. 10 is a diagram showing an example of a UFR device 2 according to a second embodiment. [Figure 8] FIG. 10 is a diagram showing an example of a control possibility determination table. [Figure 9] FIG. 10 is a diagram showing an example of a UFR device 3 according to a third embodiment. [Figure 10] FIG. 10 is a diagram showing an example of a UFR device 4 according to a fourth embodiment. [Figure 11] FIG. 10 is a diagram showing an example of a protection control system M according to a fifth embodiment. [Figure 12] FIG. 10 is a diagram showing an example of a total group number setting table. [Figure 13] FIG. 10 is a diagram showing an example of a cutoff target amount determination table. [Figure 14]FIG. 10 is a diagram showing an example of the relationship between loads sorted in order of overall group number and UF shutoff GRs including the loads, and the load power flow P. [Figure 15] FIG. 10 is a diagram showing an example of the relationship between load flow P and cutoff priority in a UF cutoff GR. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, a protection control device and a protection control system according to an embodiment will be described with reference to the drawings.

[0016] (First embodiment) First, a first embodiment will be described. Fig. 2 is a diagram showing an example of a UFR device 1 according to the first embodiment. The UFR device 1 is connected to a voltage detection unit 200 that detects the voltage of the power system and a circuit breaker 300 that breaks a load. For example, when the power system includes first to n-th lines, the UFR device 1 causes the circuit breaker 300 to break the load in each of the lines. The UFR device 1 is an example of a protection and control device.

[0017] The UFR device 1 includes, for example, a voltage acquisition unit 110, an abnormality detection unit 120, an output unit 130, a control condition setting unit 140, and a group decomposition unit 150. The voltage acquisition unit 110, the abnormality detection unit 120, the output unit 130, the control condition setting unit 140, and the group decomposition unit 150 are realized by, for example, a hardware processor such as a CPU (Central Processing Unit) (computer) executing a program (software). Furthermore, some or all of these components may be realized by hardware (including circuitry) such as an LSI (Large Scale Integration), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a GPU (Graphics Processing Unit), or may be realized by a combination of software and hardware. The program may be stored in advance in a storage device (a storage device having a non-transitory storage medium) such as a HDD or flash memory of the controller, or may be stored in a removable storage medium such as a DVD or CD-ROM, and installed in the storage device by inserting the storage medium (non-transitory storage medium) into a drive device. The program may be stored in a storage unit.

[0018] The voltage acquisition unit 110 acquires the voltage of the power system detected by the voltage detection unit 200. The abnormality detection unit 120 includes, for example, a frequency abnormality detection unit 121 and a timer unit 122. The frequency abnormality detection unit 121 measures the frequency of the power system based on the power system voltage acquired by the voltage acquisition unit 110, and determines whether an abnormal frequency state has occurred in which the frequency has dropped below a set value. The frequency abnormality detection unit 121 includes a first UFR 121-1 to an mth UFR 121-m (m: an integer equal to or greater than 1). The frequency abnormality detection unit 121 determines whether an abnormal frequency state has occurred for each group including the first UFR 121-1 to the mth UFR 121-m (hereinafter referred to as a UF cutoff group). In the following description, when components with branch numbers are not to be distinguished from one another, the branch numbers will be omitted.

[0019] The timer unit 122 measures the duration of the frequency abnormality state. The timer unit 122 has set therein a first timer time 122-1 to an m-th timer time 122-m, which are timer times for each UF cutoff group. The timer unit 122 is activated when the frequency abnormality detection unit 121 detects a frequency abnormality, measures the duration of the frequency abnormality state for each UF cutoff group, and determines whether the duration of the frequency abnormality exceeds the timer time. When the duration of the frequency abnormality exceeds the timer time, the timer unit 122 generates a control condition satisfaction signal and outputs it to the control condition setting unit 140.

[0020] The control condition setting unit 140 refers to the line group reference table when a control condition establishment signal for a UF blocking group unit is output by the timer unit 122 in the abnormality detection unit 120. Based on the result of referring to the line group reference table, the control condition setting unit 140 generates a UF blocking group unit control signal for the line group to be blocked and outputs the signal to the group decomposition unit 150.

[0021] 3 is a diagram showing an example of a line group reference table. The line group reference table is a table showing the relationship between line groups corresponding to UF cutoff group-unit control signals for m line groups. For example, in the first UFR 121-1, the first line group corresponds to the first UF cutoff group-unit control signal UF-T1 output by the abnormality detection unit 120 when the frequency abnormality state exceeds the first timer time.

[0022] Each UF blocking group includes one or more lines. FIG. 4 is a diagram showing an example of a line reference table. The line reference table is a table showing the lines included in a line group. For example, the first line group includes multiple lines, namely the first line and the second line. Also, the mth line group includes a single line, namely the nth line. The lines included in a line group are predetermined. The combination of lines included in a line group may be changeable, for example, by an administrator operating an input interface (not shown).

[0023] The group decomposing unit 150 determines the lines for which loads are to be cut off based on the UF cutoff group unit control signal output by the control condition setting unit 140. By determining the lines for which loads are to be cut off, the group decomposing unit 150 groups together the lines that need to be cut off at the same time into a line group.

[0024] The output unit 130 outputs, for example, a control command to interrupt the circuit determined by the group decomposition unit 150 to the circuit breaker 300 via an electric cable. The output unit 130 may output the control command to the circuit breaker 300 using a communication device (not shown). In this way, the UFR device 1 controls the circuit breaker 300 to interrupt the circuit in the power system.

[0025] The UFR device 1 of the first embodiment includes a control condition setting unit 140 and a group decomposing unit 150. When a control condition establishment signal is output by the timer unit 122, the control condition setting unit 140 refers to the line group reference table. Furthermore, based on the result of referring to the line group reference table, the control condition setting unit 140 generates a UF blocking group-unit control signal for the line group to be blocked and outputs it to the group decomposing unit 150. The group decomposing unit 150 determines the line whose load is to be blocked based on the UF blocking group-unit control signal output by the control condition setting unit 140. Therefore, by grouping lines that need to be blocked simultaneously into a line group, it is possible to reliably block the lines that need to be blocked simultaneously.

[0026] The lines to be grouped may be lines within the same electric power station, or may be lines between multiple electric power stations. Fig. 5 is a diagram showing an example of grouping multiple lines within the same electric power station. In the example shown on the left side of Fig. 5, within the same electric power station, a load F is connected to a power system E via a first line 1L and a second line 2L. A generator H is connected to the second line 2L. Here, a first power flow P1L flows through the first line 1L, and a second power flow P2L flows through the second line 2L.

[0027] In this example, as shown in the right diagram of Figure 5, when the first circuit 1L is shut off, the total power flow (P1L + P2L) of the first power flow P1L of the first circuit 1L and the second power flow P2L of the second circuit 2L flows to the second circuit 2L. Therefore, the total amount of load does not change, and the frequency drop cannot be resolved. In this case, to resolve the frequency drop, the first circuit 1L and the second circuit 2L within the same substation can be grouped together, allowing the first circuit 1L and the second circuit 2L to be shut off simultaneously.

[0028] Fig. 6 is a diagram showing an example of grouping multiple circuits between multiple electric power stations. In the example shown in Fig. 6, in a first electric power station Q1, a first load F1 is connected to the electric power system E via a first circuit 1L and a second circuit 2L, and a second load F2 is connected via a first connection circuit 1LA. In a second electric power station Q2, a third load F3 is connected to the electric power system E via a third circuit 3L and a fourth circuit 4L, and a generator H is connected via a second connection circuit 1LB. Here, a first power flow P1LA flows through the first connection circuit 1LA, and a second power flow P1LB flows through the second connection circuit 1LB.

[0029] In this example, the first power flow P1LA, which is the power flow through the first connection line 1LA, and the second power flow P1LB, which is the power flow through the second connection line 1LB, may have different directions. In this case, it is not possible to determine whether the power flow is toward the load (second load F2) based on the power flow direction of one of the first connection line 1LA and the second connection line 1LB. For this reason, the power flow direction is determined using the total power flow of the first power flow P1LA and the second power flow P1LB, and by grouping the lines between multiple substations, it is possible to determine whether the power flow direction is toward the load.

[0030] (Second embodiment) Next, a second embodiment will be described. The UFR device of the second embodiment differs from the first embodiment mainly in that it includes a controllability determination unit. The UFR device of the second embodiment will be described below, focusing on the differences from the first embodiment. Figure 7 is a diagram showing an example of a UFR device 2 of the second embodiment.

[0031] In the first embodiment, when a control condition establishment signal is output by the timer unit 122, the control condition setting unit 140 outputs a UF blocking group-unit control signal set by referring to the line group reference table to the group decomposing unit 150. In contrast to this, in the second embodiment, the control condition setting unit 140 outputs the generated UF blocking group-unit control signal to the control feasibility determining unit 160.

[0032] The control feasibility determination unit 160 refers to the control feasibility determination table when a UF blocking group unit control signal set by the control condition setting unit 140 is output. Based on the result of referring to the control feasibility determination table, the control feasibility determination unit 160 determines whether or not to output a UF blocking group unit control signal for the line group indicated by the UF blocking group unit control signal to the group decomposing unit 150. The conditions shown in the control feasibility determination table are examples of control feasibility conditions.

[0033] Fig. 8 is a diagram showing an example of a controllability determination table. The controllability determination table defines whether or not each of the first to m-th line groups can be used. In the example shown in Fig. 8, the first line group is deemed uncontrollable, and the second, third, and m-th line groups are deemed controllable. If the controllability determination unit 160 determines that the group is controllable, it outputs a UF blocking group-unit control signal to the group decomposition unit 150.

[0034] The possibility of control can be set, for example, by an administrator operating an input interface (not shown). For example, a line group including lines for which power supply should not be cut off, such as a hospital or a temporary construction site, may be set to be uncontrollable. Alternatively, the uncontrollable line groups may be rotated to eliminate a sense of unfairness in areas where power supply is cut off for each line or line group.

[0035] The UFR device 2 of the second embodiment has the same operational effects as the UFR device 1 of the first embodiment. Furthermore, the UFR device 2 of the second embodiment includes a controllability determination unit 160. This makes it possible to suppress the cutoff of power supply to areas where power supply cutoff is not desired, and to reduce the sense of unfairness felt in areas where power supply is cutoff.

[0036] In the second embodiment, the control feasibility determination unit 160 determines whether or not control is possible based on the UF cutoff group unit control signal output by the control condition setting unit 140, but may also determine whether or not control is possible based on a control condition satisfaction signal output by the timer unit 122 of the abnormality detection unit 120. In this case, when the control feasibility determination unit 160 determines that control is possible, it outputs the control condition satisfaction signal output by the timer unit 122 to the control condition setting unit 140.

[0037] (Third embodiment) Next, a third embodiment will be described. The UFR device of the third embodiment differs from the second embodiment mainly in that it includes a current acquisition unit, a power flow measurement unit, a group power flow calculation unit, and a power flow determination unit, and is connected to a current detection unit. The UFR device of the third embodiment will be described below, focusing on the differences from the second embodiment. Figure 9 is a diagram showing an example of a UFR device 3 of the third embodiment.

[0038] In the second embodiment, when the control condition setting unit 140 outputs a UF blocking group-unit control signal, the control feasibility determination unit 160 determines whether the line group can be controlled, and if it is determined that the line group can be controlled, it outputs the UF blocking group-unit control signal to the group decomposing unit 150. In contrast, in the third embodiment, the control feasibility determination unit 160 outputs the UF blocking group-unit control signal to the power flow determination unit 190 if it is determined that the line group can be controlled.

[0039] The UFR device 3 of the third embodiment includes, for example, a current acquisition unit 111, a power flow measurement unit 170, a group power flow calculation unit 180, and a power flow determination unit 190. The UFR device 3 is also connected to a current detection unit 210. The current acquisition unit 111 acquires the current of the power system detected by the current detection unit 210.

[0040] The power flow measurement unit 170 calculates and measures the power flow value of each circuit in the power system based on the positive / negative and magnitude of the current taken in by the current taking unit 111, and further based on the voltage taken in by the voltage taking unit 110. The power flow measurement unit 170 may measure the active power value instead of or in addition to the power flow value.

[0041] Group power flow calculation section 180 refers to the line reference table (FIG. 4) to acquire the relationships between the lines included in the line group, and calculates the total value of the power flow values, etc. of each line group based on at least one of the line power flow values ​​or active power values ​​(hereinafter referred to as power flow values, etc.) measured by power flow measurement section 170. Group power flow calculation section 180 may calculate the active power value of each line group instead of or in addition to the total value of the power flow values, etc. of each line group. Group power flow calculation section 180 generates a line group control signal according to the calculated total value of the power flow values, etc. of each line group, and outputs it to power flow determination section 190. The total value of the power flow values, etc. is an example of a total power flow value.

[0042] Power flow determination unit 190 determines whether the direction of power flow in the line group is the load direction, based on the line group control signal output by group power flow calculation unit 180. If power flow determination unit 190 determines that the direction of power flow in the line group is the load direction, it determines that control is possible under the control conditions set in control condition setting unit 140, and outputs the UF cutoff group-based control signal output by control feasibility determination unit 160 to group decomposition unit 150.

[0043] The UFR device 3 of the third embodiment has the same operational effects as the UFR device 1 of the first embodiment. Furthermore, when a line group is controllable, the UFR device 3 of the third embodiment determines that the power flow direction in the line group is the load direction before outputting a UF cutoff group-based control signal. Therefore, the power flow direction after grouping can be determined to be the load direction.

[0044] (Fourth embodiment) Next, a fourth embodiment will be described. The UFR device of the fourth embodiment differs from the third embodiment mainly in that a control avoidance determination unit is not provided. The UFR device of the fourth embodiment will be described below, focusing on the differences from the third embodiment. Figure 10 is a diagram showing an example of a UFR device 4 of the fourth embodiment.

[0045] In the third embodiment, the UF blocking unit group-by-unit signal output by the control condition setting unit 140 is output to the control feasibility determination unit 160, and when the control feasibility determination unit 160 determines that control is possible, the UF blocking unit group-by-unit control signal is output to the power flow determination unit 190. In contrast to this, in the fourth embodiment, the UF blocking unit group-by-unit signal output by the control condition setting unit 140 is output to the power flow determination unit 190.

[0046] Power flow determination unit 190 determines whether the direction of power flow in the line group is the load direction based on the line group control signal output by group power flow calculation unit 180. If power flow determination unit 190 determines that the direction of power flow in the line group is the load direction, it outputs the UF blocking group unit signal output by control condition setting unit 140 to group decomposition unit 150. As in the first embodiment, group decomposition unit 150 groups lines that need to be blocked simultaneously into a line group.

[0047] The UFR device 4 of the fourth embodiment has the same operational effects as the UFR device 1 of the first embodiment. Furthermore, the UFR device 4 of the fourth embodiment outputs a UF cutoff group-based control signal after determining that the power flow direction in the line group is the load direction. Therefore, the power flow direction after grouping can be determined to be the load direction.

[0048] (Fifth embodiment) Next, a fifth embodiment will be described. The protection and control system of the fifth embodiment includes a plurality of UFR devices and a central processing unit. The UFR device is, for example, the UFR device 3 shown in the third embodiment. The UFR device of the fifth embodiment will be described below, focusing on the differences from the third embodiment. Figure 11 is a diagram showing an example of a protection and control system M of the fifth embodiment.

[0049] The protection and control system M of the fifth embodiment includes a plurality of UFR devices, including a first UFR device 5-1, a second UFR device 5-2, and so on, and a central processing unit 500. The first UFR device 5-1, the second UFR device 5-2, and so on all have the same configuration. The first UFR device 5-1, the second UFR device 5-2, and so on have the same configuration as the UFR device 3 of the third embodiment, for example.

[0050] The first UFR device 5-1, the second UFR device 5-2, etc. all transmit the total value of the power flow values, etc. of the line groups calculated in the group power flow calculation unit 180 to the central processing unit 500. The central processing unit 500 calculates the control conditions after grouping based on the total value of the power flow values, etc. of the line groups transmitted by the UFR device 5. The central processing unit 500 transmits the calculated control conditions to the UFR device 5. The UFR device 5 generates a UF cutoff group-based control signal in the control condition setting unit 140 based on the control conditions transmitted by the central processing unit 500, and outputs it to the control feasibility determination unit 160.

[0051] In the fifth embodiment, a plurality of line groups are provided in each of a plurality of electric power stations. Fig. 12 is a diagram showing an example of an overall group number setting table. The overall group number setting table is, for example, a table showing a priority order set for each line group provided in each of a plurality of electric power stations (electric power stations No. 1 to Q). The overall group number is arbitrarily set, for example, by an administrator who manages the central processing unit 500 operating an input interface in the central processing unit 500.

[0052] The central processing unit 500, for example, sets the overall group number of the line group to be cut off and determines the target amount of cut off. When setting the overall group number of the line group, the central processing unit 500 sets an overall group number (for example, 1 to L) to each line group in each electric power station.

[0053] An overall group number is set for each line group, but the same overall group number is set for line groups that require simultaneous shutdown at multiple power stations due to, for example, a loop system. For example, if line group 1 at power station No. 1 and line group 1 at power station No. 2 are included in the same loop system, the same overall group number (overall group number 1) is set for line group 1 at power station No. 1 and line group 1 at power station No. 2.

[0054] The central processing unit 500 sets the shedding target amount based on the setting value and system capacity of each line group. For example, a line group (hereinafter referred to as UF shedding GR) is set with UF shedding GRs that are to be shedding and UF shedding GRs that are not to be shedding. For UF shedding GRs that are to be shedding, the shedding target value is set in 0.01% steps, and for UF shedding GRs that are not to be shedding, the shedding target value is set to 0.00%. The central processing unit 500, for example, sorts the line groups in order of overall group number and sequentially assigns UF shedding groups to the line groups so as to satisfy the load shedding target amount of each UF shedding GR.

[0055] 13 is a diagram showing an example of a target shutoff quantity determination table. The target shutoff quantity determination table is a table showing, for example, the target shutoff values ​​for each of M UF shutoff GRs (UF shutoff GR1 to UF shutoff GRM). The target shutoff values ​​are arbitrarily set, for example, by an administrator who manages the central processing unit 500 operating an input interface in the central processing unit 500.

[0056] The central processing unit 500 sets the target shutoff values ​​of UF shutoff GR1 to UF shutoff GRM in 0.01% steps, for example. In the example shown in FIG. 13, target shutoff values ​​other than 0.00 are set for UF shutoff GR1, 3, and 5. The target shutoff amount is, for example, a value obtained by multiplying the system capacity by the target shutoff value. For example, if the system capacity is 1000 (MW), the target shutoff amount of UF shutoff GR1 is 1000 x 0.05 = 50 (MW).

[0057] Furthermore, the target shedding amount of a lower-level line group (a line group with a higher UF shedding GR number) is the sum of the load combination selected in the higher-level line group (a line group with a lower UF shedding GR number). For example, the target shedding amount of UF shedding GR3 is calculated by multiplying the system capacity by the sum of the shedding target values ​​of UF shedding GR1 and UF shedding GR3, or 1000 x (0.05 + 0.05) = 100 (MW). For example, the target shedding amount of UF shedding GR5 is calculated by multiplying the system capacity by the sum of the shedding target values ​​of UF shedding GR1, UF shedding GR3, and UF shedding GR5, or 1000 x (0.05 + 0.05 + 0.02) = 120 (MW).

[0058] Each UF shutdown group contains multiple loads, each of which is assigned a total group number. The central processing unit 500 sorts the loads included in the UF shutdown group in order of total group number so that the loads exceed the shutdown target amount for each UF shutdown group, and sequentially selects the loads so that the load shutdown target amount is met.

[0059] Fig. 14 is a diagram showing an example of the relationship between loads sorted in order of overall group number and UF shutdown GRs including the loads, and the load power flow P. Fig. 15 is a diagram showing an example of the relationship between the load power flow P in a UF shutdown GR and shutdown priority. The shutdown priority is an index that increases as the overall group number increases.

[0060] For example, UF shutdown GR1 includes loads of total group numbers 1 to 3, and UF shutdown GR2 includes loads of total group numbers 4 to 7. In UF shutdown GR1, the load flow of total group number 1 is 10 (MW), the load flow of total group number 2 is 20 (MW), and the load flow of total group number 3 is 30 (MW). In UF shutdown GR2, the load flow of total group number 4 is 20 (MW), the load flow of total group number 5 is 10 (MW), the load flow of total group number 6 is 5 (MW), and the load flow of total group number 7 is 5 (MW).

[0061] For example, if the grid power is 1000 MW and the load shedding target value in UF shedding GR1 (hereinafter referred to as the load shedding target value) is 5%, the load shedding target amount in UF shedding GR1 is 50 MW. Also, if the load shedding target value in UF shedding GR2 is 5%, the load shedding target amount in UF shedding GR2 is 50 MW.

[0062] In this case, for example, if loads of overall group numbers 1 to 3 are selected, the shedding amount of the loads to be shedding in UF shedding GR1 (hereinafter referred to as the shedding selection amount) will be 60 (MW). Here, the shedding target amount of UF shedding GR1 and UF shedding GR2 is 100 (MW), so the shedding selection amount of UF shedding GR2 is 100-60=40 (MW).

[0063] The UFR device 5 in the protection and control system M of the fifth embodiment has the same effects as the UFR device 1 of the first embodiment. Furthermore, the protection and control system M of the fifth embodiment can treat a line group of different UFR devices 5 as one load. Therefore, the control conditions can be made the same for multiple lines, making simultaneous blocking possible.

[0064] According to at least one of the embodiments described above, by having a voltage acquisition unit that acquires the voltage of the power system, an abnormality detection unit that detects a frequency abnormality when the frequency of the acquired voltage remains below a set value for a predetermined period of time or longer, a control condition setting unit that sets control conditions for each of a plurality of line groups including a plurality of pre-set lines based on the detected frequency abnormality, a group decomposition unit that distributes a control signal to be provided to the plurality of lines included in the line group when the control condition is satisfied, and an output unit that outputs the control signal to the plurality of lines, it is possible to reliably simultaneously shut down lines that need to be shut down simultaneously.

[0065] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention described in the claims and their equivalents. [Explanation of symbols]

[0066] 1 to 4...UFR device 1, 110...voltage acquisition unit, 111...current acquisition unit, 120...abnormality detection unit, 121...frequency abnormality detection unit, 122...timer unit, 130...output unit, 140...control condition setting unit, 150...group decomposition unit, 160...control feasibility determination unit, 170...power flow measurement unit, 180...group power flow calculation unit, 190...power flow determination unit, 200...voltage detection unit, 210...current detection unit, 230...frequency abnormality detection unit, 300...circuit breaker, 500...central processing unit, E...power system, F...load

Claims

1. a voltage input unit that inputs a voltage of a power system; an abnormality detection unit that detects a frequency abnormality when the time during which the frequency of the captured voltage is equal to or less than a set value is equal to or longer than a predetermined time; a control condition setting unit that sets control conditions for each of a plurality of line groups including a plurality of lines that have been set in advance based on the detected frequency abnormality; a group decomposition unit that distributes a control signal to be provided to the plurality of lines included in the line group when the control condition is satisfied; an output unit that outputs the control signal to the plurality of lines; a control possibility determination unit that determines whether or not control is possible for each of the line groups based on a control possibility condition set for each of the line groups, Protection and control equipment.

2. a current acquisition unit that acquires a current for each of the lines; a power flow measurement unit that calculates a power flow value of each line based on the voltage and current captured by the voltage capture unit and the current capture unit; a group power flow calculation unit that calculates a total power flow value of each line group based on the power flow value of each line included in the line group measured by the power flow measurement unit, the control possibility determination unit determines whether the control is possible based on a direction indicated by a total power flow value of each line group calculated by a group power flow calculation unit. The protection and control device according to claim 1 .

3. A voltage input unit that inputs the voltage of a power grid; an abnormality detection unit that detects a frequency abnormality when the time during which the frequency of the captured voltage is equal to or less than a set value is equal to or longer than a predetermined time; a control condition setting unit that sets control conditions for each of a plurality of line groups including a plurality of lines that have been set in advance based on the detected frequency abnormality; a group decomposition unit that distributes a control signal to be provided to the plurality of lines included in the line group when the control condition is satisfied; an output unit that outputs the control signal to the plurality of lines; a current acquisition unit that acquires a current for each of the lines; a power flow measurement unit that calculates a power flow value of each line based on the voltage and current captured by the voltage capture unit and the current capture unit; a group power flow calculation unit that calculates a total power flow value of each line group based on the power flow value of each line included in the line group measured by the power flow measurement unit, the group decomposition unit distributes a control signal to be provided to the plurality of lines included in the line group when the direction indicated by the total power flow value of each line group calculated by the group power flow calculation unit is a load direction. Protection and control equipment.

4. A voltage input unit that inputs a voltage of a power system; an abnormality detection unit that detects a frequency abnormality when the time during which the frequency of the captured voltage is equal to or less than a set value is equal to or longer than a predetermined time; a control condition setting unit that sets control conditions for each of a plurality of line groups including a plurality of lines that have been set in advance based on the detected frequency abnormality; a group decomposition unit that distributes a control signal to be provided to the plurality of lines included in the line group when the control condition is satisfied; an output unit that outputs the control signal to the plurality of lines; setting a control condition for the line group based on a total power flow value obtained by adding up the power flow values ​​of each line group calculated by the protection and control device; a central processing unit that provides the set control conditions to the line group; Protection and control systems.

5. the central processing unit sets control conditions for the line groups based on the power flows for each of the line groups provided by the plurality of protection and control devices; The protection and control system according to claim 4.

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