JP7279364B2 - Sensor Abnormality Detection Apparatus and Method, Distributed Power Supply Unit, and Computer Program - Google Patents

Description

The present invention relates to a sensor abnormality detection device and method, a distributed power supply unit, and a computer program.

Distributed power supply units composed of fuel cells, solar power generators, storage batteries, etc. are becoming popular. The distributed power supply unit is connected to a power line (cable) from the grid to the load, and supplies power to the load according to the power supplied from the grid to the load and the size of the load. Such a function of the distributed power unit can reduce transmission losses due to the grid. Also, by supplying power from the distributed power supply unit to the load when the power supply from the grid drops, the operation of the device corresponding to the load can be maintained normally. Since convenience is improved by installing distributed power supply units in this way, the number of installed distributed power supply units is increasing.

When the power generated by such a distributed power supply unit increases and exceeds the power consumed by the load, surplus power is generated. If nothing is done about this surplus power, reverse power will flow into the system. However, in order to ensure the power quality of the system, such reverse power flow is often not allowed. Therefore, it is necessary to prevent reverse power flow from occurring.

For this reason, a current sensor is often provided in the power line from the system to the load. This current sensor monitors the current between the grid and the load, and controls the distributed power supply units so that reverse power flow does not occur.

Clamp-type current sensors are often used as such current sensors. A clamp-type current sensor has a measurement line consisting of windings, and by attaching the clamp-type current sensor to an electric circuit so that the winding surrounds the electric circuit with a clamp, the mutual inductance between the alternating current flowing in the electric circuit and the measurement line It outputs the current that occurs in the measurement line at the coupling. By knowing the magnitude of this current, it is possible to know the magnitude of the current flowing through the electric circuit.

Such a clamp-type current sensor can measure the magnitude of the current flowing through the electric circuit simply by attaching it to the electric circuit with a clamp. Therefore, on the one hand, installation and maintenance of the current sensor can be easily performed. On the other hand, clamp-type current sensors have the risk of falling out of the electrical circuit, being incompletely attached, or being connected in the wrong direction. When such a situation occurs, the current flowing through the electric circuit cannot be detected correctly. If the current cannot be detected correctly, the risk of reverse power flow or the like increases. Therefore, it is necessary to detect such problems immediately and take appropriate measures.

A proposal for solving such problems is made in Patent Document 1 listed below. The distributed power supply unit disclosed in Patent Document 1 includes a distributed power supply, a first current sensor to be connected to a first voltage line, and a second current sensor to be connected to a second voltage line. and a determination unit. The determination unit supplies power from the system power supply for a predetermined period of time to the power loads connected to the first and second voltage lines between the planned connection positions of the first and second current sensors and the distributed power supply. Based on the results, it is determined whether the first and second current sensors are connected, the position of the connection, and the direction of the connection.

JP 2015-122819 A

However, the technique disclosed in Patent Literature 1 energizes the internal power load of the distributed power supply unit, and determines whether or not the current sensor is connected based on the amount of change in the current measured by the current sensor before and after energization. Therefore, the distributed power supply unit must be provided with internal power loads and switches. Since the distributed power supply unit has many parts, there is a problem that the cost becomes high.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a sensor abnormality detection apparatus and method, a distributed power supply unit, and a computer program that can accurately determine whether the operation of a current sensor is normal or abnormal at a lower cost.

A sensor abnormality detection device according to a first aspect of the present invention is a sensor abnormality detection device for detecting an abnormality in a sensor attached to an electric circuit through which alternating current flows, and comprises a predetermined distributed power supply connected to the electric circuit. a measuring circuit used to control the unit for measuring the rms current of the output of the sensor; a limiting circuit for limiting the output of the distributed power supply unit so that the power supplied from the distributed power supply unit to the electric circuit is reduced by a predetermined amount; a judgment circuit for judging whether or not there is an abnormality in the sensor based on whether or not the current effective value measured by the measurement circuit after the lapse of time is equal to or less than the threshold value.

A distributed power supply unit according to a second aspect of the present invention is a distributed power supply unit connected to a single-phase three-wire AC electric circuit, wherein the single-phase three-wire AC electric circuit includes a neutral wire, including a first electric circuit and a second electric circuit, a sensor that outputs a current corresponding to the magnitude of the alternating current flowing in the first electric circuit is attached to the first electric circuit, a DC power supply, and a DC power supply and an AC circuit, a sensor abnormality detection device that determines whether or not a sensor abnormality has occurred in the sensor based on the output of the sensor, and the sensor abnormality detection device detects the occurrence of sensor abnormality. is not detected, the power conversion device is controlled based on the output of the sensor, and the control circuit for performing power conversion between DC power and AC power, and the sensor abnormality detection device generates sensor abnormality The sensor abnormality detection device includes an abnormality processing circuit for executing processing in response to a sensor abnormality in response to the detection of the sensor abnormality, the sensor abnormality detection device including a measurement circuit for measuring the current effective value of the output of the sensor, and the measurement circuit In addition, in response to the effective current value of the output of the sensor falling below a predetermined threshold, the output of the distributed power supply unit is reduced so that the power supplied from the distributed power supply unit to the electric circuit is reduced by a predetermined amount. a limiting circuit for limiting, and presence or absence of an abnormality in the sensor based on whether or not the current effective value measured by the measuring circuit after the lapse of a first predetermined time from the limit of the output of the distributed power supply unit by the limiting circuit is equal to or less than the threshold value. and a determination circuit for determining the

A sensor abnormality detection method according to a third aspect of the present invention is a sensor abnormality detection method for detecting an abnormality in a sensor attached to an electric circuit through which alternating current flows, and comprises a predetermined dispersed power supply connected to the electric circuit. a step of measuring the effective current value of the output of the sensor used to control the unit; limiting the output of the distributed power supply unit so that the power supplied from the distributed power supply unit to the electric circuit is reduced by a predetermined amount; determining whether or not there is an abnormality in the sensor based on whether or not the current effective value measured by the measurement circuit after the measurement is equal to or less than the threshold value.

A sensor abnormality detection method according to a fourth aspect of the present invention is a sensor abnormality detection method for detecting, by a computer, an abnormality in a sensor attached to an electric circuit through which an alternating current flows, wherein a predetermined dispersion connected to the electric circuit is used. a step in which the computer measures the current effective value of the output of the sensor; limiting the output of the distributed power supply units such that the power supplied to the electrical path from the distributed power supply units is reduced by a predetermined amount in response to the occurrence of a failure; determining whether or not there is an abnormality in the sensor based on whether or not the current effective value measured by the measuring circuit after the lapse of the first predetermined time from the output limitation is equal to or less than the threshold value.

A computer program according to a fifth aspect of the present invention provides a computer with a measurement step of measuring a current effective value of an output of a sensor attached to an electric circuit through which alternating current flows, and an output of the sensor measured by a measurement circuit. a limiting step of limiting the output of the distributed power supply unit so that the power supplied from the distributed power supply unit to the electric circuit is reduced by a predetermined amount in response to the effective current value falling below a predetermined threshold; a determination step of determining whether or not there is an abnormality in the sensor based on whether or not the current effective value measured by the measurement circuit after the lapse of a first predetermined time from the restriction of the output of the distributed power supply unit by the restriction circuit is equal to or less than a threshold value; to run.

According to the present invention, it is possible to provide a sensor abnormality detection device and method, a distributed power supply unit, and a computer program that can accurately determine whether the operation of a current sensor is normal or abnormal at a lower cost.

Other objects, configurations and effects of the present invention will become apparent from the accompanying drawings and the detailed description of the invention below.

FIG. 1 is a schematic diagram showing how a CT sensor senses current through an electrical path. FIG. 2 is a diagram for explaining the first procedure for attaching the CT sensor to the electric circuit. FIG. 3 is a diagram for explaining the second procedure for attaching the CT sensor to the electric circuit. FIG. 4 is a diagram for explaining the third procedure for attaching the CT sensor to the electric circuit. FIG. 5 is a schematic diagram showing a state in which a power storage system, which is an example of a distributed power supply unit, and a CT sensor are connected to a single-phase three-wire electric circuit. FIG. 6 is a graph showing an example of the output current of the CT sensor when an abnormality occurs such that the CT sensor drops out of the electrical circuit. FIG. 7 is a graph explaining a condition in which an abnormality is erroneously detected even though the CT sensor has not fallen off from the electrical circuit. FIG. 8 is a graph showing an output example of the CT sensor under the conditions of FIG. FIG. 9 is a block diagram showing the configuration of a power storage system, which is a distributed power supply unit according to the embodiment of the invention. FIG. 10 is a flow chart showing the control structure of a program for implementing the CT sensor abnormality detection method according to the embodiment of the present invention on a computer. 11 is a schematic diagram for explaining the normal operation of the power storage system shown in FIG. 9. FIG. 12 is a schematic diagram for explaining the operation of the power storage system shown in FIG. 9. FIG. FIG. 13 is a graph showing a method of preventing erroneous detection of CT sensor abnormality in the power storage system shown in FIG. 14 is a schematic diagram for explaining the operation of the power storage system shown in FIG. 9. FIG.

In the following description and drawings, identical parts are provided with identical reference numerals. Therefore, detailed description thereof will not be repeated. At least part of the embodiments described below may be combined arbitrarily.

[Description of Embodiments of the Invention]
A sensor abnormality detection device according to a first aspect of the present invention is a sensor abnormality detection device for detecting an abnormality in a sensor attached to an electric circuit through which alternating current from a system flows, and includes a predetermined sensor connected to the electric circuit. A measurement circuit used to control the distributed power supply unit that measures the effective current value of the sensor output, and when the effective current value of the sensor output measured by the measurement circuit falls below a predetermined threshold. In response, a limiting circuit for limiting the output of the distributed power supply unit so that the power supplied from the distributed power supply unit to the electric circuit is reduced by a predetermined amount; a judgment circuit for judging whether or not there is an abnormality in the sensor based on whether or not the current effective value measured by the measurement circuit after the lapse of a predetermined time is equal to or less than the threshold value.

By limiting the output of the distributed power supply unit, the power purchased from the grid for the load increases, and the current flowing in the electric circuit increases. An abnormality in the sensor is detected depending on whether or not the sensor can detect this increase in current. There is no need to provide a specific load for detecting anomalies in the sensor or to provide a switch for switching the power supply from the external load to the internal load. Therefore, it is possible to detect an abnormality of the sensor with a simple configuration and a low risk of erroneous determination without extra cost.

Preferably, the limiting circuit includes a detection circuit for detecting that the effective current value of the sensor output, measured by the measurement circuit, has continuously fallen below the threshold value for a first predetermined time or longer; The power supplied from the distributed power supply unit to the electric circuit is reduced by a predetermined amount in response to detection by the detection circuit that the effective current value has continuously fallen below the threshold value for a first predetermined time period or more. and circuitry for limiting the output of the distributed power supply unit.

When the power supplied from the distributed power supply unit to the electric circuit decreases, power is supplied from the grid to compensate for the power consumption of the load. Therefore, if the current flowing through the electrical path immediately before that is zero and the sensor output cannot be detected, current will flow through the electrical path. Whether or not the sensor is abnormal can be determined based on whether or not the sensor can detect this current.

More preferably, the determination circuit determines whether or not the current effective value measured by the measurement circuit is continuously equal to or less than a threshold value after a second predetermined period of time has elapsed since the limit circuit limited the output of the distributed power supply unit. It includes a continuation determination circuit that determines whether or not there is an abnormality in the sensor.

If the sensor cannot detect the current flowing through the electric circuit even after the second predetermined time has elapsed, it can be determined that the sensor has an abnormality. Conversely, if the sensor can detect the current, it can be determined that the sensor is normal.

More preferably, the sensor abnormality detection device further preferably determines that the current effective value measured by the measurement circuit after a second predetermined time has elapsed since the limit circuit limits the output of the distributed power supply unit is equal to or less than the threshold value. A shutdown device is included for shutting down the distributed power supply units in response to the determination by the determination circuit.

Since the distributed power supply unit can be stopped when an abnormality of the sensor is detected, the occurrence of reverse power flow or the like can be prevented.

Preferably, the sensor abnormality detection device further includes a determination circuit that the current effective value measured by the measurement circuit exceeds a threshold value after a second predetermined time has passed since the limit circuit limits the output of the distributed power supply unit. a release device for releasing the restriction of the output of the distributed power supply unit by the limiter circuit to return the distributed power supply unit to a normal state in response to the determination of

If the current effective value exceeds the threshold value after the second predetermined time, it can be determined that there is no abnormality in the sensor. Therefore, the distributed power supply unit can be restored to a normal state.

More preferably, the sensor abnormality detection device further includes a prohibition circuit that prohibits operation of the limit circuit for a third predetermined time after the release device releases the restriction on the output of the distributed power supply unit.

If processing for sensor abnormality detection is started immediately after returning the distributed power supply unit to a normal state, the output of the distributed power supply unit may become unstable depending on the conditions. Therefore, after the dispersed power supply units return to the normal state, the output of the dispersed power supply units is not restricted for a third predetermined time. As a result, it is possible to prevent the output of the distributed power supply unit from becoming unstable.

A distributed power supply unit according to a second aspect of the present invention is a distributed power supply unit connected to a single-phase three-wire AC electric circuit, wherein the single-phase three-wire AC electric circuit includes a neutral wire, including a first electric circuit and a second electric circuit, a sensor that outputs a current corresponding to the magnitude of the alternating current flowing in the first electric circuit is attached to the first electric circuit, a DC power supply, and a DC power supply and an AC circuit, a sensor abnormality detection device that determines whether or not a sensor abnormality has occurred in the sensor based on the output of the sensor, and the sensor abnormality detection device detects the occurrence of sensor abnormality. is not detected, the power conversion device is controlled based on the output of the sensor, and the control circuit for performing power conversion between the DC power supply and the AC power on the AC circuit, and the sensor abnormality detection device is the sensor and an abnormality processing circuit for executing a process when the sensor is abnormal in response to detecting the occurrence of an abnormality. the distributed power supply unit such that the power supplied from the distributed power supply unit to the circuit is reduced by a predetermined amount in response to the rms current value of the output of the sensor falling below a predetermined threshold value as measured by and a limiting circuit for limiting the output of the sensor according to whether or not the current effective value measured by the measuring circuit after the lapse of a first predetermined time from the limit of the output of the distributed power supply unit by the limiting circuit is equal to or less than the threshold value. and a determination circuit for determining the presence or absence of an abnormality.

By limiting the output of the distributed power supply unit, the power purchased from the grid for the load increases, and the current flowing in the electric circuit increases. An abnormality in the sensor is detected depending on whether or not the sensor can detect this increase in current. There is no need to provide a specific load for detecting anomalies in the sensor or to provide a switch for switching the power supply from the external load to the internal load. Therefore, it is possible to detect an abnormality of the sensor with a simple configuration and a low risk of erroneous determination without extra cost.

Preferably, the predetermined amount is an amount of power that is a constant percentage of the power supplied from the distributed power supply unit to the electric line.

By reducing the amount of power by a certain percentage, the amount of power reduction can be easily determined.

A sensor abnormality detection method according to a third aspect of the present invention is a sensor abnormality detection method for detecting an abnormality in a sensor attached to an electric circuit through which alternating current flows, and comprises a predetermined dispersed power supply connected to the electric circuit. a step of measuring the effective current value of the output of the sensor used to control the unit; limiting the output of the distributed power supply unit so that the power supplied from the distributed power supply unit to the electric circuit is reduced by a predetermined amount; determining whether or not there is an abnormality in the sensor based on whether or not the current effective value measured by the measurement circuit after the measurement is equal to or less than the threshold value.

By limiting the output of the distributed power supply unit, the power purchased from the grid for the load increases, and the current flowing in the electric circuit increases. An abnormality in the sensor is detected depending on whether or not the sensor can detect this increase in current. There is no need to provide a specific load for detecting anomalies in the sensor or to provide a switch for switching the power supply from the external load to the internal load. Therefore, it is possible to detect an abnormality of the sensor with a simple configuration and a low risk of erroneous determination without extra cost.

Preferably, the sensor anomaly detection method further includes repeating the limiting step and the determining step at least once in response to a positive determination in the determining step.

When the electric power is decreased by a predetermined amount, if the load is decreased at the same time, there is a risk of erroneously detecting sensor abnormality. By repeating the limiting step and the determining step at least once, the risk of erroneous detection can be reduced.

A sensor abnormality detection method according to a fourth aspect of the present invention is a sensor abnormality detection method for detecting, by a computer, an abnormality in a sensor attached to an electric circuit through which an alternating current flows, wherein a predetermined dispersion connected to the electric circuit is used. a step in which the computer measures the current effective value of the output of the sensor; limiting the output of the distributed power supply units such that the power supplied to the electrical path from the distributed power supply units is reduced by a predetermined amount in response to the occurrence of a failure; determining whether or not there is an abnormality in the sensor based on whether or not the current effective value measured by the measuring circuit after the lapse of the first predetermined time from the output limitation is equal to or less than the threshold value.

By limiting the output of the distributed power supply unit, the power purchased from the grid for the load increases, and the current flowing in the electric circuit increases. An abnormality in the sensor is detected depending on whether or not the sensor can detect this increase in current. There is no need to provide a specific load for detecting anomalies in the sensor or to provide a switch for switching the power supply from the external load to the internal load. Therefore, it is possible to detect an abnormality of the sensor with a simple configuration and a low risk of erroneous determination without extra cost.

A computer program according to a fifth aspect of the present invention provides a computer with a measurement step of measuring a current effective value of an output of a sensor attached to an electric circuit through which alternating current flows, and an output of the sensor measured by a measurement circuit. a limiting step of limiting the output of the distributed power supply unit so that the power supplied from the distributed power supply unit to the electric circuit is reduced by a predetermined amount in response to the effective current value falling below a predetermined threshold; a determination step of determining whether or not there is an abnormality in the sensor based on whether or not the current effective value measured by the measurement circuit after the lapse of a first predetermined period of time from the restriction of the output of the distributed power supply unit by the restriction circuit is equal to or less than a threshold value; to run.

By limiting the output of the distributed power supply unit, the power purchased from the grid for the load increases, and the current flowing in the electric circuit increases. An abnormality in the sensor is detected depending on whether or not the sensor can detect this increase in current. There is no need to provide a specific load for detecting anomalies in the sensor or to provide a switch for switching the power supply from the external load to the internal load. Therefore, it is possible to detect an abnormality of the sensor with a simple configuration and a low risk of erroneous determination without extra cost.

[Details of Embodiments of the Invention]
<Configuration>
The embodiments described below take a single-phase three-wire distributed power supply unit as an example. Also, in this example, a CT sensor is used as an example of the sensor.

Referring to FIG. 1, CT sensor 50 includes donut-shaped core 54 and winding 56 wound around core 54 . When the CT sensor 50 is attached to the electric circuit 52 so that the electric circuit 52 through which alternating current flows passes through the center of the core 54, a magnetic flux corresponding to the magnitude of the current flowing through the electric circuit 52 is generated, A large alternating current flows. When this current is passed through the shunt resistor 58, a voltage Vout is generated across it. Distributed power supply units that perform power conversion, such as grid-connected storage systems and solar power conditioners, input this voltage Vout to an instrumentation circuit to measure the value of alternating current flowing through the grid.

A voltage Vout generated across the shunt resistor 58 is obtained by the following equation.

Vout=coupling coefficient×secondary current×shunt resistance/number of turns The coupling coefficient is an element related to the degree of coupling of the CT sensor, such as excitation current, leakage flux, change in magnetic permeability, etc. The coupling coefficient is 1 in an ideal CT sensor.

Referring to FIG. 2, more specifically, the CT sensor 50 includes a resin housing 84 in which a core component 82, which is the lower half of the core 54, is embedded in the upper portion, and one side of the upper surface of the resin housing 84. Mounted shaft 86 and resin-made resin mounted on shaft 86 so as to be rotatable around shaft 86 at a limited angle between a position that closes the upper surface of resin housing 84 and a position that opens it. and an upper housing 88 . A core component 80 that is the upper half of the core 54 is embedded in the lower surface of the upper housing 88 .

As shown in FIG. 2, the CT sensor 50 is attached to the electric circuit 52 so that the electric circuit 52 is positioned inside the core component 82 with the upper housing 88 separated from the resin housing 84, and the upper housing is shown in FIG. 88 covers the upper surface of the resin housing 84 . Furthermore, as shown in FIG. 4, when the core component 80 and the core component 82 are brought into close contact with each other by biasing force using springs 90 and 92 provided on the upper part of the upper housing 88, the CT sensor 50 is firmly attached to the electric circuit 52. Core component 80 and core component 82 form core 54 shown in FIG.

Referring to FIG. 5, in an exemplary configuration including an energy storage system, an energy storage system 138 powers a single-phase, three-wire system 130 having a neutral wire 134 and L1 and L2 wires 132 and 136. conduct. An L1 load 140 is connected between the neutral wire 134 and the L1 wire 132 by electric circuits 154 and 156, and an L2 load 142 is connected between the neutral wire 134 and the L2 wire 136 by electric circuits 158 and 160. is connected. A conventional storage system 138 is connected to L1 line 132 by line 148 , to neutral line 134 by line 150 , and to L2 line 136 by line 152 . The storage system 138 is further connected to an L1 side CT sensor 144 attached to the L1 line 132 and an L2 side CT sensor 146 attached to the L2 line 136 . The power storage system 138 measures the magnitude of the alternating current flowing through the L1 line 132 and the L2 line 136 from the outputs of the L1 side CT sensor 144 and the L2 side CT sensor 146, and adjusts the values so that they match the target values aimed at by the entire system. to control the inside of the power storage system 138 .

By the way, for example, it is assumed that the output of the L2 side CT sensor 146 changes as shown in FIG. That is, it is assumed that the current effective value 200 flowing through the L1 line 132 is higher than the predetermined threshold value (area 202 shown in FIG. 6) until time _tx . After that, at time _t0 , the current effective value becomes equal to or less than the threshold value, and the threshold value continues until time _t1 (region 204 in FIG. 6) when the determination period for determining abnormality of the CT sensor has elapsed. value below. Then, the power storage system 138 determines that the CT sensor has some abnormality (for example, the CT sensor is disconnected from the electric circuit or the winding of the CT sensor is broken) at time _t1 .

However, the change in current effective value 200 shown in FIG. 6 occurs not only when the CT sensor is abnormal, but also when other specific conditions are met. In such a case, if it is determined that an abnormality has occurred in the CT sensor, it will be an erroneous determination of the abnormality of the CT sensor.

FIG. 7 shows a diagram in which an electricity storage system 280 as an example of the distributed power supply unit according to the embodiment of the present invention is adopted in place of the conventional electricity storage system 138 in the configuration shown in FIG. Referring to FIG. 7, it is assumed that the L1 side load 140 is 3000 W and the L2 side load 142 is 2000 W, for example. It is also assumed that the maximum output rating of power storage system 280 is 4000W. The power storage system 280 then supplies maximum output to both the L1 side load 140 and the L2 side load 142 . In the case of the power storage system 280 that is controlled by two lines as in this embodiment, the output to the L1 line 132 and the L2 line 136 cannot be controlled separately. 20 A is supplied to the L2 side load 142 via the electric circuit 152, respectively. Since the L1 side load 140 requires 30A, it is short by 10A. This 10A will be purchased from system 130 . On the other hand, in the L2 side load 142, all the required 20 A is supplied from the power storage system 280, so the power purchased from the grid 130 is 0, and the current flowing through the L2 line 136 is 0.

At this time, when the power storage system 280 calculates the current effective value flowing through the L2 line 136 from the output of the L2 side CT sensor 146, the current effective value 240 is, as shown in FIG. would show similar changes. That is, the current effective value, which was greater than the threshold in the region 242 until time t _y , falls below the threshold at time t _y . If this state continues for the determination period as indicated by region 244, the conventional technology will erroneously determine that some abnormality has occurred in the L2 side CT sensor 146 at time _t2 . However, in the power storage system 280 of this embodiment, such a determination error is prevented by the following configuration and operation.

FIG. 9 shows a schematic configuration of the power storage system 280. As shown in FIG. Referring to FIG. 9, power storage system 280 includes storage battery 300, capacitor 302 connected between both terminals of storage battery 300, DC reactor 304 having one end connected to the positive terminal of storage battery 300, and DC reactor 304 DCDC converter 306 connected to the other end of storage battery 300 and the negative terminal of storage battery 300, DC bus 308 connected to the other high voltage side terminal and low voltage side terminal of DCDC converter 306, and DC bus 308 and an intermediate capacitor 330 .

The power storage system 280 further includes an inverter 307 whose DC side is connected to the DC bus 308, an AC reactor 328 connected to the AC side of the inverter 307, an AC side capacitor 332 connected to the system side of the AC reactor 328, and an AC A common mode choke coil 334 connected to the AC reactor 328 on the AC side of the side capacitor 332, a capacitor 336 connected to the AC side of the common mode choke coil 334, and the AC side of the common mode choke coil 334 are connected from the system side. and a disconnect switch 310 for disconnecting.

The power storage system 280 further includes a fuse 312 provided between one end of the cutoff switch 310 and the grid side, and a fuse 314 connected in series between the other end of the fuse 312 and the other end of the cutoff switch 310. and a varistor 316 . The contacts of fuse 314 and fuse 312 are connected to the L1 line of the system. The other end of varistor 316 is connected to the L2 line of the system.

The power storage system 280 further includes sensors 350, 352, 354, 356, 358, and 360 that measure the current and voltage of each part of this circuit and output measurement signals, and the DCDC converter 306 and the inverter 307 based on these measurement signals. It includes a control circuit 320 for outputting a gate control signal for controlling the on/off of the included transistors and a switch control signal for controlling the isolation switch 310 .

The DCDC converter 306 includes a high side transistor Q1 and a low side transistor Q2 connected together, and two diodes connected antiparallel to the high side transistor Q1 and the low side transistor Q2, respectively. One end of a DC reactor 304 is connected to the contact of the high voltage side transistor Q1 and the low voltage side transistor Q2.

Inverter 307 includes four full-bridge-connected transistors Q3, Q4, Q5, and Q6 and four diodes connected anti-parallel to each of these transistors.

The contacts of the transistors Q3 and Q4 are connected to one end of the AC reactor 328 on the DC side, and the contacts of the transistors Q5 and Q6 are connected to the other end of the AC reactor 328 on the DC side.

The control circuit 320 includes a microcomputer and a storage device (not shown), and is equipped with an A/D conversion circuit and a D/A conversion circuit (not shown). A control program executed by the control circuit 320 is stored in this storage device. This program A/D-converts measurement signals from various sensors, executes predetermined arithmetic processing, and outputs a digital signal that determines the on/off state of each transistor Q1 to Q6 based on the data obtained as a result. . The signal is converted to an analog signal for gate control by a D/A conversion circuit (not shown) and applied to each transistor.

The control structure of the program executed by the control circuit 320 will be described below. The following description is for determining whether or not the L2 side CT sensor 146 for measuring the current value of the L2 line 136 shown in FIG. 5 is abnormal. A program for determining whether or not there is an abnormality in the L1 side CT sensor 144 for measuring the current value of the L1 line 132 is similarly configured and executed in parallel with this program.

Referring to FIG. 10, the program executed by control circuit 320 performs initialization such as securing a storage area on the memory, clearing the input/output buffer, self-diagnosis, and reading necessary setting data after the program starts executing. and a step 452 of controlling the on/off of each transistor according to the measurement signals of various sensors and the target value to perform the charge/discharge operation, as described above.

Note that the following control uses the first, second, third and fourth variables. The first variable is for measuring the time since the current rms value of the L2 line 136 fell below the threshold. When this time exceeds a predetermined threshold value, in this embodiment, the output from power storage system 280 is reduced by a predetermined amount. The second variable is for measuring the elapsed time since the discharge power of the power storage system 280 was decreased. If no change is seen in the output of the L2 side CT sensor 146 even after a predetermined elapsed time, it is tentatively determined that the CT sensor has fallen off, and the output of the L2 side CT sensor 146 is detected before the predetermined elapsed time. exceeds the threshold value, it is assumed that the CT sensor has not fallen off, and the decrease in the discharge power of the storage system 280 is stopped. The third variable is for measuring elapsed time since discharge power was discontinued. If normal processing is started immediately after stopping the reduction of discharge power, there is a risk that the output of power storage system 280 will become unstable. Therefore, after stopping the reduction of the discharge power of the storage system 280, the reduction of the power of the storage system 280 for the abnormality determination of the L2 side CT sensor 146 as described above is prohibited until a certain period of time elapses. . The fourth variable counts how many times the second variable has been used to prima facie determine that the CT sensor has fallen off. When the fourth variable exceeds a predetermined upper limit, a final determination is made that the CT sensor has fallen off.

After step 452, the program further includes step 454 for determining whether the value of the third variable is 0 and branching the flow of control according to the result of the determination; Step 456 counts down the value of the variable 3 by 1 and returns control to step 452, and if the determination in step 454 is affirmative, whether or not the CT sensor current of the L2 side CT sensor 146 is equal to or less than a predetermined threshold value. and branch the flow of control according to the result of the determination, and step 460 of resetting the value of the first variable to 0 and returning the control to step 452 when the determination of step 458 is negative. include. The determination in step 456 becomes negative until a predetermined time has passed after the return to the normal state. That is, during this period, abnormality determination regarding the L2 side CT sensor 146 is prohibited. After a predetermined period of time has passed, the determination in step 456 becomes affirmative, and the prohibition of abnormality determination is lifted.

This program further includes step 462 for counting up the value of the first variable by 1 when the determination at step 458 is affirmative, and following step 462, whether or not the count value of the first variable is greater than or equal to a certain value. and step 464 for branching the flow of control according to. Control returns to step 452 when the determination at step 464 is negative.

The program further includes step 465 of resetting the fourth variable to 0 when the determination of step 464 is affirmative, and limiting the discharge power P of the storage system 280 to a predetermined ΔP [W] (for example, ΔP= 0.1×P), and following step 466, a step of determining whether or not the current effective value of the L2 side CT sensor 146 is equal to or less than the threshold value, and branching the control flow according to the determination result. 468, a step 470 of resetting the values of both the first and second variables and returning the discharge power to its original value when the determination at step 468 is negative; and step 472 of substituting a predetermined value for the variable and returning control to step 452 . The processing of step 470 lifts the restriction on the discharge power. In order to determine whether or not the L2 side CT sensor 146 is abnormal, in principle, the output of the power storage system 280 may be increased. However, in that case, there is a possibility that the power output from the power storage system 280 will flow backward to the grid, which is not preferable. Therefore, in order to perform processing similar to that of this embodiment at least in power storage system 280 connected to the grid, it is preferable to adopt a method of temporarily limiting the output of power storage system 280 .

This program further determines whether or not the discharged power of the power storage system 280 is approximately 0 when the determination at step 468 is affirmative, and branches the control flow at step 473 and the determination at step 473 is negative. At step 474, the value of the second variable is counted up by 1, and after step 472, it is determined whether or not the count value of the second variable has exceeded a certain value. a step 476 for returning control to step 468; a step 477 for counting up the fourth variable when the determination in step 476 is affirmative; and step 478 which returns control to step 466 . When the determination in step 478 is affirmative, the control proceeds to step 480, where it is finally determined that the L2 side CT sensor 146 has fallen off from the L2 line 136, and the processing when an abnormality is detected in the CT sensor (stopping operation of the power storage system 280. notification). When the determination at step 473 is affirmative, the control proceeds directly to step 476 without performing the processing at step 474 .

It should be noted that the execution of this program is stopped by interrupt processing that is executed in response to an interrupt generated by the operation of an operation stop button (not shown) provided in the power storage system 280, occurrence of an abnormality that causes some kind of control stop, and It is performed in response to the occurrence of a power failure or the like. The reason why the processing from step 465 to step 478 is repeated while decreasing the discharge power by ΔP [W] is that when the magnitude of the load happens to decrease by the same magnitude when the processing of step 466 is performed, This is because there is a possibility of erroneously detecting an abnormality in the CT sensor. By repeating the processing from step 465 to step 478 (as long as the determination at step 468 is affirmative) until the count value of the fourth variable reaches the upper limit number of times, the risk of such erroneous detection can be reduced. Even repeating these steps once can greatly reduce the risk of erroneous detection. Note that the upper limit of the count value of the fourth variable can be any value. Furthermore, although it is considered to be a rare example, when the discharge power becomes almost 0 in step 473, it is necessary to stop counting up the second variable, so the processing of step 474 is skipped.

<Action>
The power storage system 280 described above operates as follows. Although the following description relates only to the L2 side CT sensor 146, the same processing is executed in parallel for the L1 side CT sensor 144 as well.

Referring to FIG. 11, in a normal state, L1 side CT sensor 144 and L2 side CT sensor 146 input CT sensor currents corresponding to the currents flowing through L1 line 132 and L2 line 136 to power storage system 280, respectively. This current (analog signal) is A/D converted by an A/D conversion circuit (not shown) in the power storage system 280 and input to the control circuit 320 shown in FIG. Inputs from various sensors 350 , 352 , 354 , 356 , 358 , and 360 are also input to the control circuit 320 after A/D conversion.

Control circuit 320 controls L1-side load 140 and L2-side load 140 with output power from power storage system 280 according to these values and a preset target purchased power value so that purchased power does not exceed the target value. The DCDC converter 306 and the inverter 307 shown in FIG. 9 are controlled so as to cover the power consumption of the load 142 and prevent reverse power flow from occurring.

For example, in the example shown in FIG. 11, it is assumed that the power storage system 280 outputs a maximum rated output of 4000W. In this case, 20 A is output from the power storage system 280 to both the L1 line 132 and the L2 line 136 and supplied to the L1 side load 140 and the L2 side load 142, respectively. Assuming that the L1 side load 140 and the L2 side load 142 are both 3000 W, 20 A is insufficient. In order to make up for the power shortage, 20 A is purchased from the system, and 10 A is supplied to the L1 side load 140 via the L1 line 132 and 10 A is supplied to the L2 side load 142 via the L2 line 136, respectively.

In this case, the program for sensor abnormality detection repeats the operation of steps 452→454→458→460→452 in a state where no abnormality occurs, referring to the flow chart of FIG. The control of the DCDC converter 306 and the inverter 307 by the control circuit 320 is performed at step 452 . Since the content of this control is not directly related to the present invention, the details will not be described here.

On the other hand, for example, as shown in FIG. 7, it is assumed that the load of the L1 side load 140 is 3000W and the load of the L2 side load 142 is 2000W. In this case also, the power storage system 280 outputs the maximum output rating of 4000W. That is, the power storage system 280 provides a current of 20 A to the L1 load 140 via the L1 line 132 and a current of 20 A to the L2 load 142 via the L2 line 136 . Then, as described above, 10 A flows from the grid to the L1 line 132 due to the purchased power in order to make up for the shortage of power to the L1 side load 140 . On the other hand, since the power required by the L2 side load 142 is completely covered by the 20A from the power storage system 280, the power flowing from the system to the L2 line 136 is 0A.

In this case, the following control is executed in the power storage system 280 according to this embodiment. Under such circumstances, the effective value of the output current of the L2 side CT sensor 146 becomes small and falls below the threshold value. Referring to FIG. 10, in this case the determination at step 458 is affirmative and step 462 counts up the first variable. Because the first variable is initialized to 0 in step 450, the value of the first variable will be 1 the first time the situation described above occurs. At subsequent step 464, it is determined whether or not the count value of the first variable is equal to or greater than a predetermined value. As this constant value, a value corresponding to an elapsed time of about 0.1 to 0.5 seconds is used. While the value of the first variable is small compared to this value, control iteratively passes through the path of steps 464→452→454→458→462→464. If the effective value of the output current of L2 side CT sensor 146 exceeds the threshold halfway through, the determination at step 458 becomes negative, the first variable is reset at step 460, and power storage system 280 returns to normal operation. If the effective value of the output current of the L2 side CT sensor 146 continues to be below the threshold for a certain period of time, the determination in step 464 becomes affirmative, and the processing from step 465 onwards is executed.

A fourth variable is reset to zero at step 465 . At subsequent step 466, the discharged power from the power storage system 280 is reduced by ΔP [W]. For example, assume that 1/10 of the maximum output rating of 4000 W, that is, 400 W is adopted as ΔP. Then, a total of 3600 W is output from the power storage system 280 . That is, 18 A (1800 W) is supplied from the power storage system 280 to the L1 side load 140 via the L1 line 132 and 18 A (1800 W) is also supplied to the L2 side load 142 via the L2 line 136 . As a result, the power shortage to the L1 side load 140 is 1200 W, and power of only 12 A (1200 W) is purchased from the grid. A current of 12 A flows through the L1 line 132 . On the other hand, a shortage of 200 W occurs in the power supplied to the L2 side load 142 . To make up for the shortfall, only 2A (200W) of power is purchased from the grid. A current of 2 A flows through the L2 line 136 .

If the L2 side CT sensor 146 is normal, it should detect this current (2 A). That is, referring to FIG. 13, it is assumed that the detected current 400 of the L2 side CT sensor 146 exceeds the threshold value in a region 402 (before time _tz ), and the load of the L2 side load 142 is reduced at time _tz . shall be reduced. As a result, the detected current 400 output by the L2 side CT sensor 146 becomes equal to or less than the threshold. Let that point of time be time _t0 . Assuming that the detected current 400 was below the threshold during the period A (region 404 in FIG. 13) before the discharge power from the power storage system 280 was reduced, the discharge power from the power storage system 280 was reduced after a certain period of time. is decreased, the current flowing through the L2 line 136 increases, and if the L2 side CT sensor 146 is normal, the rms value of the output detection current 400 should exceed the threshold at some point. Conversely, if the detected current 400 output from the L2 side CT sensor 146 does not change and is equal to or less than the threshold value, it can be determined that some abnormality has occurred in the L2 side CT sensor 146 .

Referring to FIG. 10 again, if the L2 side CT sensor 146 is normal, after step 466, the control repeats the processing of steps 468→473→474→476→468 several times. The determination is affirmative and the process proceeds to step 470 . Thereafter, the first and second variables are reset at step 470 to restore the discharge power and control returns to step 452 for normal operation. However, a predetermined value is set to the third variable in step 472, and the processing from step 458 onwards is not started until the processing of steps 452→454→step 456 is repeated a predetermined number of times. This is because the output of power storage system 280 may become unstable if the already-described sensor abnormality detection process is started immediately after the operation returns to the normal mode. Therefore, during the period B (area 406) in FIG. 13, the sensor abnormality detection process is not performed. After period B elapses, power storage system 280 returns completely to normal operating mode.

Referring to FIG. 10, if the detected current 400 of L2 side CT sensor 146 continues to be equal to or less than the threshold even after a certain period of time has passed, it is tentatively assumed that some abnormality has occurred in L2 side CT sensor 146. A determination is made and the determination at step 476 is affirmative. Control proceeds to step 477 and the fourth variable is counted up. At subsequent step 478, it is determined whether or not the count value of the fourth variable is equal to or greater than a predetermined upper limit. If the value of the fourth variable is not equal to or greater than the upper limit (if the determination in step 478 is negative), control returns to step 466 to further reduce the discharge power of power storage system 280 by ΔP [W], and the above processing is repeated. be If the determination at step 478 is affirmative as a result of repeating such processing, the processing at the time of detection of CT omission of step 480 is executed.

If there is no abnormality in the CT sensor and there is no change in the load value, the processing of steps 466 to 476 is repeated several times and then the determination of step 468 becomes negative, returning to normal processing. If the load value decreases at the same timing as step 466, even if the processing of steps 466 to 476 is repeated a fixed number of times, the determination of step 468 will not become affirmative, and the determination of step 476 will finally become affirmative. As a result, there is a risk that the CT sensor will be tentatively determined to be abnormal. In this embodiment, to deal with this risk, a fourth variable is used to repeat steps 466-478 up to a predetermined upper limit number of times. If there is no abnormality in the CT sensor, there is a high probability that the determination in step 468 will be negative when the discharge power of the power storage system 280 is decreased several times. Therefore, in this case, it returns to normal operation. If there is an abnormality in the CT sensor, there is a high probability that the determination at step 468 will remain affirmative even if the above processing is repeated. Therefore, when the determination in step 478 is affirmative, it can finally be determined that an abnormality has occurred in the CT sensor.

A typical one of such abnormalities is the dropout of the L2 side CT sensor 146 from the L2 line 136 as shown in FIG. If the L2 side CT sensor 146 is disconnected from the L2 line 136, the L2 side CT sensor 146 cannot detect the current (eg, 2 A) flowing through the L2 line 136. Therefore, the effective value of the detected current 400 output from the L2 side CT sensor 146 becomes equal to or less than the threshold, and the power storage system 280 stops operating.

The process of reducing the output of the power storage system 280 in step 466 of FIG. 10 may be performed by, for example, a limiter. Also, in the case of a system connected to grid power, such as the power storage system 280, the same effect can be obtained by setting the target purchased power value high.

When the load value fluctuates greatly during the period A of FIG. 13, if the L2 side CT sensor 146 is normal, its detection current 400 will also change, and the determination at step 468 will become negative, and before the predetermined time elapses You can return to normal operation.

As described above, according to the present invention, it is possible to erroneously determine that the CT sensor is abnormal when a certain relationship is established between the output of a distributed power supply unit such as a power storage system and the power consumption of a load. can be prevented. It is possible to appropriately determine the operating state of the distributed power supply unit and maintain the operation in a preferable state. At this time, there is no need to provide a specific load for detecting a CT sensor abnormality in the distributed power supply unit, or to provide a switch for switching the supplied power from the external load to the internal load. Therefore, it is possible to detect an abnormality in a CT sensor with a simple configuration and a low risk of erroneous determination without extra cost.

The amount of decrease ΔP [W] when the output of the storage system is decreased in step 466 of FIG. 10 may be a fixed amount, but it is generally considered to be a predetermined percentage of the current discharge power. . For example, values such as 10%, 20%, 30%, 50% of the current discharge power can be adopted. These values are considerations at the time of designing, and should be large enough to reliably detect erroneous detection of the CT sensor. Even in that case, the rate need not be constant, and the rate of decrease may gradually decrease. Conversely, if there is no problem, the value of ΔP may be gradually increased. Typically, a certain percentage (eg, 10%) of the discharged power of the storage system when step 466 is executed, for example, can be set as ΔP. In this way, the calculation for making the determination in step 473 can be easily performed.

The embodiments disclosed this time are merely examples, and the present invention is not limited only to the above-described embodiments. The scope of the present invention is indicated by each claim after taking into account the description of the detailed description of the invention, and all changes within the meaning and range equivalent to the wording described therein include.

Q1 High-voltage side transistor Q2 Low-voltage side transistors Q3, Q4, Q5, Q6 Transistor 50 CT sensor 52, 148, 150, 152, 154, 156, 158, 160 Electric circuit 54 Core 56 Winding 58 Shunt resistance 80, 82 Core part 84 Resin Housing 86 Shaft 88 Upper housing 90, 92 Spring 130 System 132 L1 line 134 Neutral line 136 L2 line 138, 280 Power storage system 140 L1 side load 142 L2 side load 144 L1 side CT sensor 146 L2 side CT sensor 200, 240 , 400 current effective values 202, 204, 242, 244, 402, 404, 406 area 300 storage batteries 302, 336 capacitor 304 DC reactor 306 DCDC converter 307 inverter 308 DC bus 310 cutoff switch 312, 314 fuse 316 varistor 320 control circuit 328 alternating current Reactor 330 Intermediate capacitor 332 AC side capacitor 334 Common mode choke coil 350, 352, 354, 356, 358, 360 Sensor 400 Detection current 450, 452, 454, 456, 458, 460, 462, 464, 465, 466, 468, 470, 472, 473, 474, 476, 477, 478, 480 steps

Claims (9)

A sensor abnormality detection device for detecting an abnormality in a sensor attached to an electric circuit in which a system power and a load are connected and in which an alternating current flows, the predetermined distributed power supply unit connected to the electric circuit. wherein the sensor is located between the grid power and a connection point of the load to the electric circuit, and further between the connection point between the distributed power supply unit and the electric circuit and the system power connected to the electric circuit between
a measurement circuit that repeatedly measures the effective current value of the output of the sensor;
a limiting circuit for limiting the output of the distributed power supply unit so that the power supplied from the distributed power supply unit to the electric path is reduced by a predetermined amount from the power supplied immediately before;
In response to the lapse of a first predetermined time period in which the effective current value of the output of the sensor measured by the measurement circuit is equal to or less than a predetermined threshold value, the distributed power supply unit outputs the a first limit instruction circuit for instructing the limit circuit to reduce the power supplied to the electrical path from the power supplied immediately before it by the predetermined amount , and for initializing the value of a predetermined count variable ;
The current effective value measured by the measurement circuit is no longer equal to or less than the threshold value by the time a second predetermined time elapses after the output of the distributed power supply unit is limited by the instruction from the first limitation instruction circuit. a normality determination circuit for determining that the sensor is normal in response to the
The current effective value measured by the measurement circuit continues to be equal to or less than the threshold value until the second predetermined time elapses after the output of the distributed power supply unit is limited by the instruction from the first limit instruction circuit. , the value of the count variable is counted up, and if the value of the count variable is within a predetermined range, the power supplied from the distributed power supply unit to the electric path is increased from the power supplied immediately before that a second limit instruction circuit that instructs the limit circuit to decrease by the predetermined amount;
and an abnormality determination circuit that determines that the sensor is abnormal in response to the fact that the value of the count variable is outside the predetermined range . 2. The sensor abnormality detection apparatus according to claim 1 , further comprising a stop device for stopping said distributed power supply unit in response to said abnormality determination circuit determining that said sensor is abnormal. Furthermore, in response to the normality determination circuit determining that the sensor is normal, the limitation of the output of the distributed power supply unit by the limiter circuit is lifted to restore the distributed power supply unit to a normal state. 3. The sensor malfunction detection device of claim 2 , including a release device for enabling. 4. The sensor abnormality detection device according to claim 3 , further comprising a prohibition circuit that prohibits the operation of said limiter circuit for a fourth predetermined time after the release of the restriction on the output of said distributed power supply unit by said release device. A distributed power supply unit connected to a single-phase three-wire AC line connected to system power and a load, wherein the single-phase three-wire AC line includes a neutral line, a first line, and and a second electric circuit, wherein the first electric circuit is attached with a sensor that outputs a current corresponding to the magnitude of the alternating current flowing in the first electric circuit, the sensor of the first electric circuit, between the system power and the connection point of the load to the first electric line, and further between the connection point between the distributed power supply unit and the AC electric line and the system power; attached to the power line,
a DC power supply;
a power conversion device provided between the DC power supply and the AC electric circuit;
a sensor abnormality detection device that determines whether or not a sensor abnormality has occurred in the sensor based on the output of the sensor;
When the sensor abnormality detection device does not detect the occurrence of sensor abnormality, the power conversion device is controlled based on the output of the sensor, and power conversion is performed between the DC power supply and the AC power on the AC electric circuit. a control circuit for causing
an abnormality processing circuit for executing a process when the sensor abnormality occurs in response to the sensor abnormality detection device detecting the occurrence of a sensor abnormality,
The sensor abnormality detection device is
a measurement circuit that repeatedly measures the effective current value of the output of the sensor;
a limiting circuit for limiting the output of the distributed power supply unit so that the power supplied from the distributed power supply unit to the AC electric line is reduced by a predetermined amount from the power supplied immediately before;
In response to the lapse of a first predetermined time period in which the effective current value of the output of the sensor measured by the measurement circuit is equal to or less than a predetermined threshold value, the distributed power supply unit outputs the a first limit instruction circuit for instructing the limit circuit to reduce the power supplied to the alternating current line from the power supplied immediately before it by the predetermined amount, and for initializing the value of a predetermined count variable ;
The current effective value measured by the measurement circuit is no longer equal to or less than the threshold value by the time a second predetermined time elapses after the output of the distributed power supply unit is limited by the instruction from the first limitation instruction circuit. a normality determination circuit for determining that the sensor is normal in response to the
The current effective value measured by the measurement circuit continues to be equal to or less than the threshold value until the second predetermined time elapses after the output of the distributed power supply unit is limited by the instruction from the first limit instruction circuit. , the value of the count variable is counted up, and if the value of the count variable is within a predetermined range, the power supplied from the distributed power supply unit to the AC electric line is increased to the power supplied immediately before that a second limit instruction circuit that instructs the limit circuit to decrease by the predetermined amount from
and an abnormality determination circuit that determines that the sensor is abnormal in response to the fact that the value of the count variable is outside the predetermined range . 6. The distributed power supply unit according to claim 5 , wherein said predetermined amount is a power amount that is a constant percentage of the power supplied from said distributed power supply unit to said AC electric line. A sensor abnormality detection method for detecting an abnormality in a sensor attached to an electric circuit in which an alternating current flows and which is connected to a system power and a load, and is used for controlling a predetermined distributed power supply unit connected to the electric circuit. and the sensor is connected between the grid power and a connection point of the load to the power line, and further between a connection point between the distributed power supply unit and the power line and the power line. Further, the distributed power supply unit limits the output of the distributed power supply unit so that the power supplied from the distributed power supply unit to the electric circuit is reduced by a predetermined amount from the power supplied immediately before that power supply. A limiting circuit is provided,
repeatedly measuring the current rms value of the output of the sensor;
in response to the lapse of a first predetermined time period in which the effective current value of the output of the sensor measured in the measuring step continues to be equal to or less than a predetermined threshold value, the distributed power supply unit a first limit instructing step of instructing the limit circuit to reduce the power supplied to the electrical circuit from the immediately preceding power supply by the predetermined amount and initializing the value of a predetermined count variable;
The current effective value measured in the measuring step is equal to or less than the threshold value within a second predetermined time after the output of the distributed power supply unit is limited by the instruction in the first limitation instruction step. A normality determination step of determining that the sensor is normal in response to being no longer
The current effective value measured in the measuring step continues to be equal to or less than the threshold value until the second predetermined time elapses after the output of the distributed power supply unit is restricted by the instruction in the first restriction instruction step. , the value of the count variable is counted up, and if the value of the count variable is within a predetermined range, the power supplied from the distributed power supply unit to the electric path is increased from the power supplied immediately before that a second limit instruction step of instructing the limit circuit to decrease by the predetermined amount;
and an abnormality determination step of determining that the sensor is abnormal in response to the fact that the value of the count variable is outside the predetermined range . A sensor abnormality detection method for detecting, by a computer, an abnormality in a sensor attached to an alternating current electric circuit connected to a grid power supply and a load, and controlling a predetermined distributed power supply unit connected to the electric circuit. wherein the sensor is located between the grid power and a connection point of the load to the electric circuit, and further between the connection point between the distributed power supply unit and the electric circuit and the grid power The distributed power supply unit mounted on the electric circuit limits the output of the distributed power supply unit so that the power supplied from the distributed power supply unit to the electric circuit is reduced by a predetermined amount from the power supplied immediately before that. A limiting circuit is provided,
a computer repeatedly measuring the current rms value of the output of the sensor;
The distributed power supply in response to the lapse of a first predetermined time period in which the current effective value of the output of the sensor measured in the measuring step continues to be equal to or less than a predetermined threshold value, a first limit instructing step of instructing the limiter circuit to reduce the power supplied from the unit to the electrical path by the predetermined amount from the power supplied immediately before it, and initializing the value of a predetermined count variable;
By the time a second predetermined time elapses after the output of the distributed power supply unit is restricted by the instruction in the first restriction instruction step, the computer determines that the current effective value measured in the measuring step exceeds the threshold. A normality determination step of determining that the sensor is normal in response to being no longer below the value;
until the second predetermined time elapses after the output of the distributed power supply unit is restricted by the instruction in the first restriction instruction step, the computer continues to measure the effective current value in the step of measuring; In response to being equal to or less than the threshold value, the value of the count variable is counted up, and if the value of the count variable is within a predetermined range, the electric power supplied from the distributed power supply unit to the electric path immediately before that a second limit instruction step of instructing the limit circuit to reduce the supply power by the predetermined amount;
and an abnormality determination step, wherein the computer determines that the sensor is abnormal in response to the fact that the value of the count variable is outside the predetermined range . to the computer,
A computer program for executing a measurement step of repeatedly measuring a current effective value of an output of a sensor attached to an alternating current line connected to a grid power supply and a load, the predetermined distributed type connected to the line line The sensor is used to control a power supply unit, and the sensor is located between the grid power and a connection point of the load to the electric circuit, and further, a connection point between the distributed power supply unit and the electric circuit and the system power. The distributed power supply unit is mounted on the electric circuit between and further, the distributed power supply unit is arranged so that the power supplied from the distributed power supply unit to the electric circuit is reduced by a predetermined amount from the power supplied immediately before it. A limiting circuit is provided to limit the output of the unit,
The computer program further comprises:
In response to the lapse of a first predetermined time period in which the effective current value of the output of the sensor measured in the measuring step continues to be equal to or less than a predetermined threshold value , from the distributed power supply unit to the a first limit instructing step of instructing the limit circuit to reduce the power supplied to the electrical path from the power supplied immediately before it by the predetermined amount and initializing the value of a predetermined count variable;
By the time a second predetermined time elapses after the output of the distributed power supply unit is limited by the instruction in the first limitation instruction step, the current effective value measured in the measurement step is no longer equal to or less than the threshold value. a normality determination step of determining that the sensor is normal in response to the
The current effective value measured in the measuring step continues to be equal to or less than the threshold value until the second predetermined time elapses after the output of the distributed power supply unit is restricted by the instruction in the first restriction instruction step. , the value of the count variable is counted up, and if the value of the count variable is within a predetermined range, the power supplied from the distributed power supply unit to the electric path is increased from the power supplied immediately before that a second limit instruction step of instructing the limit circuit to decrease by the predetermined amount;
and an abnormality determination step of determining that the sensor is abnormal in response to the fact that the value of the count variable is outside the predetermined range .

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