JP7728205B2 - Protection and control device and protection and control system - Google Patents

Description

Embodiments of the present invention relate to a protection control device and a protection control system.

Under-frequency relays (UFR) are protective and control devices in power systems, such as frequency drop countermeasure devices (see, for example, Non-Patent Document 1). Frequency drop in power systems occurs when supply (power) is low relative to demand within the system, due to factors such as power source failure or system isolation. By installing multiple UFR devices within a power system and shedding predetermined loads when the frequency drops, it is possible to maintain the supply and demand balance within the power system and restore the frequency.

Figure 1 shows 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 cuts off the load. The circuit breaker 100 is connected to the circuit breaker 300, for example, via an electric cable. For example, when the power system includes a first line through an n-th line (n: an integer greater than or equal to 1), the UFR device 100 causes the circuit breaker 300 to cut off the load on each of the lines.

The voltage acquisition unit 110 acquires the power system voltage 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 in 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 the 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.

The timer unit 122 measures the duration of the frequency anomaly state. The timer unit 122 has timer times set for each line, from the first timer time 122-1 to the n-th timer time 122-n. 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.

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. If the power system includes the first through nth circuits, the output unit 130 includes the first output unit 130-1 through the nth output unit 130-n. The first output unit 130-1 through the nth output unit 130-n output control commands to shed the loads of the first through nth circuits of the power system, respectively. The UFR device sheds the load for each circuit.

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

In addition, 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 along the first circuit 1L or second circuit 2L, the current values of the first circuit 1L and 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.

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 the lines of different UFR devices need to be shut down simultaneously, those lines must be treated as a single load.

Here, conventional UFR devices 100 set the setting value of the frequency anomaly detection unit 230 and the timer value of the timer unit on a line-by-line basis, so for lines that need to be shut off simultaneously, the setting value and timer value were set to the same. 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 shut off simultaneously, in which case the lines that need to be shut off simultaneously cannot be shut off simultaneously.

Akihiko Yokoyama and Koji Ota, "Power System Stabilization System Engineering," Institute of Electrical Engineers of Japan, 2014

The problem that this invention aims to solve is to provide a protection control device and protection control system that can reliably simultaneously shut down circuits that need to be shut down simultaneously.

The protection and control device of this embodiment has 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 the 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 multiple line groups, each group including multiple pre-set lines, based on the detected frequency abnormality. The group decomposition unit distributes control signals to the multiple lines included in the line group when the control conditions are met. The output unit outputs the control signals to the multiple lines.

FIG. 1 is a diagram showing an example of a conventional UFR device 100. FIG. 1 is a diagram showing an example of a UFR device 1 according to a first embodiment. FIG. 10 is a diagram showing an example of a line group reference table. FIG. 10 is a diagram showing an example of a line reference table. FIG. 10 is a diagram showing an example of grouping multiple circuits within the same power station. FIG. 10 is a diagram showing an example of grouping a plurality of lines between a plurality of electric power stations. FIG. 10 is a diagram showing an example of a UFR device 2 according to a second embodiment. FIG. 10 is a diagram showing an example of a control possibility determination table. FIG. 10 is a diagram showing an example of a UFR device 3 according to a third embodiment. FIG. 10 is a diagram showing an example of a UFR device 4 according to a fourth embodiment. FIG. 10 is a diagram showing an example of a protection control system M according to a fifth embodiment. FIG. 10 is a diagram showing an example of a total group number setting table. FIG. 10 is a diagram showing an example of a cutoff target amount determination table. 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. FIG. FIG. 10 is a diagram showing an example of the relationship between load flow P and cutoff priority in UF cutoff GR.

The protection control device and protection control system of the embodiment will be described below with reference to the drawings.

(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 a first line to an n-th line, the UFR device 1 causes the circuit breaker 300 to break a load on each line. The UFR device 1 is an example of a protection and control device.

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 a hardware processor, such as a CPU (Central Processing Unit) (computer), executing a program (software). Some or all of these components may be realized by hardware (including circuitry) such as an LSI (Large Scale Integration), ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Gate Array), or 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 with a non-transitory storage medium) such as the controller's HDD or flash memory, or may be stored on a removable storage medium such as a DVD or CD-ROM, and installed in the storage device when the storage medium (non-transitory storage medium) is inserted into a drive device. The program may also be stored in a storage unit.

The voltage acquisition unit 110 acquires the power system voltage 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 power system frequency 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 drops below a set value. The frequency abnormality detection unit 121 includes the first UFR 121-1 to the mth UFR 121-m (m: an integer greater than or equal to 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 UFR blocking group). In the following description, when components with branch numbers are not distinguished, the branch numbers will be omitted.

The timer unit 122 measures the duration of the frequency abnormality state. The timer unit 122 has timer times set for each UF cutoff group, from the first timer time 122-1 to the m-th timer time 122-m. 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. If the duration of the frequency abnormality exceeds the timer time, the timer unit 122 generates a control condition establishment signal and outputs it to the control condition setting unit 140.

When the timer unit 122 in the abnormality detection unit 120 outputs a control condition establishment signal for a UF blocking group, the control condition setting unit 140 references the line group reference table. Based on the results of referencing the line group reference table, the control condition setting unit 140 generates a UF blocking group-based control signal for the line group to be blocked and outputs it to the group decomposition unit 150.

Figure 3 shows an example of a line group reference table. The line group reference table is a table that shows 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.

Each UF blocking group contains one or more lines. Figure 4 shows an example of a line reference table. The line reference table is a table that shows the lines contained in a line group. For example, the first line group contains multiple lines, the first line and the second line. The mth line group contains a single nth line. The lines contained in a line group are predetermined. The combination of lines contained in a line group may be changed, for example, by an administrator operating an input interface (not shown).

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

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 electrical cable. The output unit 130 may also 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.

The UFR device 1 of the first embodiment comprises a control condition setting unit 140 and a group decomposition unit 150. When a control condition establishment signal is output by the timer unit 122, the control condition setting unit 140 references the line group reference table. Furthermore, based on the results of referencing 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 decomposition unit 150. The group decomposition unit 150 determines the line for which to block loads 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 lines that need to be blocked simultaneously.

The lines to be grouped may be lines within the same power station, or may be lines between multiple power stations. Figure 5 is a diagram showing an example of grouping multiple lines within the same power station. In the example shown on the left side of Figure 5, within the same 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.

In this example, as shown in the right diagram of Figure 5, if the first line 1L is shut off, the total power flow (P1L + P2L) of the first power flow P1L on the first line 1L and the second power flow P2L on the second line 2L will flow on the second line 2L. As a result, the total load does not change, and the frequency drop cannot be resolved. In this case, to resolve the frequency drop, the first line 1L and the second line 2L can be grouped within the same power station, allowing the first line 1L and the second line 2L to be shut off simultaneously.

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

In this example, the direction of the first power flow P1LA, which is the power flow of the first connection line 1LA, and the direction of the second power flow P1LB, which is the power flow of the second connection line 1LB, may differ. 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 power stations, it is possible to determine whether the power flow is toward the load.

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.

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-based control signal set by referring to the line group reference table to the group decomposition unit 150. In contrast, in the second embodiment, the control condition setting unit 140 outputs the generated UF blocking group-based control signal to the control feasibility determination unit 160.

When a UF blocking group-unit control signal set by the control condition setting unit 140 is output, the control feasibility determination unit 160 refers to the control feasibility determination table. Based on the results of each reference to the control feasibility determination table, the control feasibility determination unit 160 determines whether 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 decomposition unit 150. The conditions shown in the control feasibility determination table are examples of control feasibility conditions.

Figure 8 shows an example of a controllability determination table. The controllability determination table defines whether or not each of the first through mth line groups can be used. In the example shown in Figure 8, the first line group is not controllable, while the second, third, and mth line groups are controllable. If the controllability determination unit 160 determines that control is possible, it outputs a UF blocking group-based control signal to the group decomposition unit 150.

Whether or not control is possible can be set by an administrator operating an input interface (not shown), for example. For example, if the lines in a line group include lines for which power supply should not be cut off, such as a hospital or a temporary construction site, the line group 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.

The UFR device 2 of the second embodiment achieves the same effects as the UFR device 1 of the first embodiment. Furthermore, the UFR device 2 of the second embodiment is equipped with a controllability determination unit 160. This makes it possible to prevent power supply cutoffs in areas where power supply cutoffs are not desired, and reduces the sense of unfairness felt in areas where power supply is cutoff.

In the second embodiment, the control feasibility determination unit 160 determines whether control is possible based on the UF shutoff group-unit control signal output by the control condition setting unit 140, but it may also determine whether control is possible based on the control condition satisfaction signal output by the timer unit 122 of the abnormality detection unit 120. In this case, if 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.

(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.

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

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 grid detected by the current detection unit 210.

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 captured by the current capture unit 111, and the voltage captured by the voltage capture unit 110. The power flow measurement unit 170 may measure the active power value instead of or in addition to the power flow value.

The group power flow calculation unit 180 refers to the line reference table (Figure 4) to obtain the relationship between the lines included in the line group, and calculates the total value of the power flow values, etc. for 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 the power flow measurement unit 170. The group power flow calculation unit 180 may calculate the active power value for each line group instead of or in addition to the total value of the power flow values, etc. for each line group. The group power flow calculation unit 180 generates a line group control signal corresponding to the calculated total value of the power flow values, etc. for each line group, and outputs this to the power flow determination unit 190. The total value of the power flow values, etc. is an example of a total power flow value.

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

The UFR device 3 of the third embodiment achieves the same 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.

(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.

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

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

The UFR device 4 of the fourth embodiment achieves the same 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.

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.

The protection and control system M of the fifth embodiment includes multiple UFR devices, namely, a first UFR device 5-1, a second UFR device 5-2, etc., and a central processing unit 500. The first UFR device 5-1, the second UFR device 5-2, etc., all have the same configuration. The first UFR device 5-1, the second UFR device 5-2, etc., have the same configuration as, for example, the UFR device 3 of the third embodiment.

The first UFR device 5-1, second UFR device 5-2, etc. each transmit the total value of the power flow values, etc. of the line group 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 group 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 blocking 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.

In the fifth embodiment, multiple line groups are provided in each of multiple electric power stations. Figure 12 shows an example of an overall group number setting table. The overall group number setting table is, for example, a table showing the priority order set for each line group provided in each of multiple electric power stations (electric power stations No. 1 to Q). The overall group number is set arbitrarily, for example, by an administrator managing the central processing unit 500 operating an input interface on the central processing unit 500.

The central processing unit 500, for example, sets the overall group number of the line group to be cut off and determines the target cutoff amount. When setting the overall group number of the line group, the central processing unit 500 assigns an overall group number (e.g., 1 to L) to each line group at each electric power station.

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.

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

Figure 13 shows an example of a target shutoff quantity determination table. The target shutoff quantity determination table is a table that shows, 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 set arbitrarily, for example, by an administrator managing the central processing unit 500 operating the input interface on the central processing unit 500.

The central processing unit 500 sets the target shutoff values for UF shutoff GR1 to UF shutoff GRM in 0.01% increments, for example. In the example shown in Figure 13, target shutoff values other than 0.00 are set for UF shutoff GR1, 3, and 5. The target shutoff amount is, for example, the system capacity multiplied by the target shutoff value. For example, if the system capacity is 1000 (MW), the target shutoff amount for UF shutoff GR1 is 1000 x 0.05 = 50 (MW).

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

There are multiple loads within a UF shutdown GR, and these multiple loads are assigned overall group numbers. The central processing unit 500 sorts the loads included in the UF shutdown GR in order of overall group number so that the loads exceed the shutdown target amount for each UF shutdown GR, and sequentially selects loads so that the load shutdown target amount is met.

Figure 14 shows an example of the relationship between loads sorted in order of overall group number and UF shutdown GRs that include the loads, and the load flow P. Figure 15 shows an example of the relationship between load flow P in a UF shutdown GR and shutdown priority. The shutdown priority is an index that increases as the overall group number increases.

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

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

In this case, for example, if loads from 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, since the shedding target amount for UF shedding GR1 and UF shedding GR2 is 100 (MW), the shedding selection amount for UF shedding GR2 will be 100 - 60 = 40 (MW).

The UFR device 5 in the protection and control system M of the fifth embodiment achieves 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 line groups of different UFR devices 5 as a single load. Therefore, the control conditions can be made identical for multiple lines, making simultaneous disconnection possible.

In at least one embodiment described above, by having a voltage acquisition unit that acquires the voltage of the power system, an anomaly detection unit that detects a frequency anomaly 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 containing a predetermined number of lines based on the detected frequency anomaly, a group decomposition unit that distributes control signals to the multiple lines included in the line group when the control conditions are met, and an output unit that outputs the control signals to the multiple lines, it is possible to reliably simultaneously shut down lines that need to be shut down simultaneously.

While 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 may be embodied in a variety of other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. These embodiments and their variations are within the scope of the invention and its equivalents as defined in the claims, as well as the scope and spirit of the invention.

1-4...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 (5)

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. 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 . 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 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. 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. 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 .