JP2012085444A - Insulation monitoring device for charge and discharge system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an insulation monitoring device monitoring an insulation state of a charge and discharge system, which stores power generated by a solar light panel 11 in a battery 15 and operates a load 12 by using the power stored in the battery 15, with high accuracy.SOLUTION: A switching part 16 is provided between a solar light panel 11 and a battery 15 and between a load 12 and the battery 15. By operating the switching part 16, any one of a charging state, a discharging state, and a neutral state is selected. A DC current sensor 14 is installed on electric lines L1 and L2 connecting the switching part 16 with the battery 15 to detect a current flowing in the electric lines L1 and L2. Based on the detected current, occurrence of a ground fault is detected. An occurrence position of the ground fault is specified depending on a connection position of the switching part 16 at the time when the ground fault is detected. Accordingly, when the ground fault occurs, the occurrence position can be recognized in real time, and thus, a quick response can be taken.

Description

  The present invention relates to a charge / discharge system that charges a battery with DC power generated by a generator and supplies the power charged to the battery to drive the load, and in particular, monitors deterioration of the insulation state. The present invention relates to an insulation monitoring device.

  In recent years, with the development of generators using natural energy, the spread of charge / discharge systems using solar panels is increasing. A charging / discharging system using a solar panel charges a generated electric power in a battery (power storage means), and then supplies the electric power charged in the battery to various loads to operate the load. . For example, a battery is charged with electric power generated by a solar panel during daytime, and is used as electric power for charging a vehicle battery using electric power stored in the battery at night.

  In such a charge / discharge system, a ground fault (leakage or insulation failure) may occur in the solar panel, load, battery, or various devices that connect them, and this is detected immediately when a ground fault occurs. Therefore, it is necessary to take measures such as cutting off the battery. Therefore, a conventional method has been proposed in which a DC ground detector is provided between the battery and the power converter to detect a ground failure in the circuit on the output side of the battery and to shut off the battery connection circuit when a ground failure occurs. (For example, refer to Patent Document 1).

JP 2005-245185 A

  However, although the conventional example disclosed in Patent Document 1 described above can detect a ground fall between the battery and the power converter, there is a drawback that the insulation state in the entire system cannot be monitored. there were.

  The present invention has been made in order to solve such a conventional problem, and an object of the present invention is to store the power generated by the generator in the power storage means and use the power stored in the power storage means. Another object of the present invention is to provide an insulation monitoring device for a charge / discharge system that can accurately monitor the insulation state of the charge / discharge system that operates the load.

  In order to achieve the above object, the invention described in claim 1 of the present application is directed to a DC power supply that outputs generated power as DC power (for example, DC power obtained by rectifying the output of a solar panel or the power generated by a wind power generator). Etc.), a storage means (for example, battery 15) for storing DC power output from the DC power supply, and a charge / discharge system provided with a load that operates when supplied with the power stored in the storage means In an insulation monitoring apparatus for monitoring a state, a direct current detection means (for example, a current) that detects a current flowing in at least one of an electric wire connecting the DC power supply and the power storage means, and an electric wire connecting the power storage means and the load. An insulation state monitor that monitors an insulation state of at least one of the DC power supply and the load based on the current detected by the sensor 14) and the DC current detection means. Means (for example, the control device 13) and alarm means (for example, the CPU 21) that outputs an alarm signal when the insulation monitoring means determines that the insulation state of the DC power supply or the load is defective. , Provided.

  The invention according to claim 2 further includes switching means (for example, a switching unit 16) that selectively connects a connection terminal of the power storage means to the DC power source or the load, and the switching means and the connection The DC current detecting means is provided in an electric wire (for example, L1, L2) connecting the terminal.

  According to a third aspect of the present invention, the connection terminal of the power storage means is connected to any one of the DC power supply, the load, and a neutral position that is not connected to any of the DC power supply and the load. Further, a switching means (for example, a switching unit 16) is further provided, and the DC current detection means is provided in an electric wire (for example, L1, L2) connecting the switching means and the connection terminal.

  According to a fourth aspect of the present invention, the insulation state monitoring unit is configured to insulate the switching unit based on a current detected by the DC current detection unit when the switching unit is connected to the neutral position. The state is judged.

  According to a fifth aspect of the present invention, the DC power source is a solar panel, and the switching unit is connected to the solar panel and the power storage unit according to the illuminance near the solar panel, or One of connections between the load and the power storage means is selected.

  In the insulation monitoring apparatus for a charge / discharge system according to the present invention, at least one of a wire connecting a DC power source (for example, the solar panel 11) and a power storage means (for example, the battery 15), and a wire connecting the power storage means and a load. DC current detection means for detecting the current flowing through the DC current detection means is provided, and a ground fault (insulation failure) is detected based on the current detected by the DC current detection means. Therefore, when a ground fault occurs, it is possible to easily identify the ground fault location in the charge / discharge system, and to quickly deal with the ground fault. Further, since the ground fault of the entire system can be detected by one current sensor and one insulation state monitoring means, the apparatus configuration can be reduced in scale and the overall cost can be reduced.

It is a block which shows the structure of the charging / discharging system to which the insulation monitoring apparatus which concerns on one Embodiment of this invention is applied. It is a block diagram which shows the detailed structure of the control apparatus of the insulation monitoring apparatus which concerns on one Embodiment of this invention. It is a flowchart which shows the process sequence of the insulation monitoring apparatus which concerns on one Embodiment of this invention. It is a flowchart which shows the process sequence of the insulation monitoring apparatus which concerns on one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a charge / discharge system provided with an insulation monitoring apparatus according to an embodiment of the present invention. As shown in the figure, this charge / discharge system includes, for example, a solar panel 11 (DC power supply) provided in a general home, and a battery (power storage means) 15 that charges DC power generated by the solar panel 11. Any one of the load 12 driven by the electric power charged in the battery 15, the connection between the solar panel 11 and the battery 15, the connection between the load 12 and the battery 15, or the connection between the neutral point and the battery 15. And a switching section 16 (switching means) that switches so that one is selected.

  In addition, the electric wires L1 and L2 connecting the switching unit 16 and the battery 15 are provided with a current sensor 14 (DC current detecting means) that detects DC currents In and Ip flowing through the electric wires L1 and L2. The sensor 14 is connected to the control device 13 (insulation state monitoring means). The electric wire L1 is connected to the negative terminal of the battery 15, and the electric wire L2 is connected to the positive terminal of the battery 15.

  The load 12 is, for example, a home appliance or an electric vehicle, and is driven by being supplied with DC power output from the battery 15. When the load 12 is an AC load, an inverter device (not shown) for converting DC power to AC power may be provided between the battery 15 and the battery 12.

  The switching unit 16 includes two switches SW1 and SW2 that operate in conjunction with each other, and can be switched to three positions under the control of the control device 13. That is, the charging state in which the contacts a1 and a4 are connected and the contacts b1 and b4 are connected, the contact a2 and a4 are connected, the neutral state in which the contacts b2 and b4 are connected, the contacts a3 and a4 are connected, and the contact b3 And b4 are selected and connected in a discharge state.

  When the charging state is selected, the solar panel 11 and the battery 15 are connected, and the DC power generated by the solar panel 11 is supplied to the battery 15 via the electric wires L1 and L2, and the battery 15 To charge.

  When the discharge state is selected, the load 12 and the battery 15 are connected, and the DC power charged in the battery 15 is supplied to the load 12 via the electric wires L1 and L2 to drive the load 12. Make it possible.

  When the neutral state is selected, the two connection terminals (+, −) of the battery 15 are in a neutral state that is not connected to either the solar panel 11 or the load 12.

  The details of the current sensor 14 and the control device 13 will be described below with reference to the block diagram shown in FIG. As shown in FIG. 2, the current sensor 14 includes a detection coil 32 and an excitation coil 31. The detection coil 32 has a circular shape having a central opening (not shown), and the electric wires L1 and L2 are inserted through the central portion. Further, in a state where the excitation coil 31 is wound around the detection coil 32, a current is passed through the excitation coil 31 to excite the detection coil 32. As a result, it is possible to detect a direct current that is the difference between the current flowing through the electric wire L1 and the current flowing through the electric wire L2.

  In addition, the control device 13 includes a CPU 21 that performs overall control including processing for generating and outputting an excitation signal for exciting the excitation coil 31, and a low-pass that removes high-frequency components of the excitation signal generated by the CPU 21. A filter 22, an amplifier 23 that amplifies the excitation signal output from the low-pass filter 22, and an excitation output unit 24 that outputs the excitation signal amplified by the amplifier 23 and supplies the excitation signal to the excitation coil 31 of the current sensor 14. I have.

  Further, the control device 13 is input at the detection signal input unit 27 based on the detection signal input unit 27 for inputting a current signal detected by the detection coil 32 of the current sensor 14 and the excitation signal output from the CPU 21. A synchronous detection unit 26 that synchronously detects the detected signal, and a low-pass filter 25 that removes a high-frequency component of the detection signal output from the synchronous detection unit 26.

  And CPU21 detects the electric current which flows into the electric wires L1 and L2 shown in FIG. 1 based on the detection signal output from the low-pass filter 25. FIG. Specifically, a current that is the difference between the current In flowing through the electric wire L1 and the current Ip flowing through the electric wire L2 is detected.

  Further, the CPU 21 outputs a switch control signal to the switching unit 16 and executes a process of switching the connection state of the switches SW1 and SW2 to any one of the above-described charging state, discharging state, and neutral state. For example, if an illuminance sensor (not shown) is installed in the vicinity of the solar panel 11 and the illuminance sensor determines that it is daytime, switches SW1 and SW2 are connected to the a1 and b1 sides, respectively. When it is determined that it is in the charged state and at night, the switches SW1 and SW2 are connected to the a3 and b3 sides, respectively, and controlled to be in the discharged state. Further, when the preset time is reached (for example, the time set every hour) or when the switching operation by the operator is performed, the switches SW1 and SW2 are connected to the a2 and b2 sides, respectively. Then, control is performed to achieve a neutral state.

  Further, when a current exceeding a preset threshold current (for example, 10 mA) is detected based on the current detected by the detection coil 32, the CPU 21 detects a ground fault (insulation) at any point in the charge / discharge system. It is determined that the state is bad), and processing for outputting an alarm signal to the host system or the like is executed. That is, when a ground fault has not occurred in the charge / discharge system, the current In flowing through the electric wire L1 and the current Ip flowing through the electric wire L2 are equal to each other. , Ip cancels each other and becomes almost zero. On the other hand, the fact that the current is detected by the current sensor 14 means that the current In flowing through the minus terminal and the current Ip flowing through the plus terminal are not balanced, and a ground fault occurs at any point. Is determined to have occurred. In this embodiment, when a current of 10 mA or more is detected by the current sensor 14, it is determined that a ground fault has occurred. That is, the CPU 21 has a function as an alarm unit that outputs an alarm signal when the insulation state monitoring unit determines that the DC power supply or the load insulation state is defective. In addition, the electric current determined to be a ground fault is not limited to 10 mA. Further, the host system is a system that is provided at a location separated from the charge / discharge system, for example, and receives the alarm signal through data communication to monitor the entire charge / discharge system.

  In addition, when the CPU 21 determines that a ground fault has occurred, when the switches SW1 and SW2 of the switching unit 16 illustrated in FIG. 1 are connected to the a1 and b1 sides (charged state), sunlight is generated. When it is determined that the ground (current I1) is generated in the panel 11, and SW1 and SW2 are connected to a3 and b3 (discharge state), the ground (current I2) is generated in the load 12. Judge that you are doing. Further, when SW1 and SW2 are connected to a2 and b2 (neutral state), it is determined that the ground (current I3) is generated in the switching unit 16.

  Next, the operation of the insulation monitoring apparatus according to this embodiment configured as described above will be described. 3 and 4 are flowcharts showing a processing procedure performed by the CPU 21 of the control device 13.

  First, the CPU 21 determines whether or not it is a predetermined inspection timing set in advance (step S11). This inspection timing is determined, for example, as a designated time once a day, an hourly interval, or the like. If it is this inspection timing (YES in step S11), the processing in step S31 shown in FIG. 4 is performed. move on.

  If it is not the inspection timing (NO in step S11), the CPU 21 detects the current (current that is the difference between Ip and In) flowing through the electric wires L1 and L2 connected to the battery 15 by the current sensor 14 ( Step S12).

  The CPU 21 determines whether or not the current detected by the current sensor 14 is 10 mA or more and this current has continued for 5 seconds or more (step S13). If it is determined that a current of 10 mA or more has not continued for 5 seconds or longer (NO in step S13), the process ends.

  On the other hand, when it is determined that a current of 10 mA or more has continued for 5 seconds or more (YES in step S13), it is determined whether or not the switches SW1 and SW2 of the switching unit 16 are connected to the solar panel 11 side. (Step S14). That is, it is determined whether or not the switches SW1 and SW2 are connected to the a1 and b1 sides, respectively.

  And when it determines with it being connected to the solar panel 11 side (it is YES at step S14), it determines with the groundfall having generate | occur | produced in the solar panel 11 (step S16), and a high-order system. An alarm signal for notifying this is output.

  On the other hand, when it is determined that it is not connected to the solar panel 11 side (NO in step S14), it is determined whether or not the switches SW1 and SW2 of the switching unit 16 are connected to the load 12 side ( Step S15). That is, it is determined whether the switches SW1 and SW2 are connected to the a3 and b3 sides, respectively.

  If it is determined that the load is connected to the load 12 (YES in step S15), it is determined that a ground failure has occurred in the load 12 (step S17), and this is notified to the host system. An alarm signal for notification is output.

  If it is a predetermined inspection timing (YES in step S11), the switches SW1 and SW2 are switched to the neutral point. That is, the switches SW1 and SW2 are switched so as to be connected to a2 and b2, respectively (step S31 in FIG. 4).

  Thereafter, current detection by the current sensor 14 is performed (step S32), and it is determined whether or not the current detected by the current sensor 14 is 10 mA or more and the current continues for 5 seconds or more (step S33). If it is determined that a current of 10 mA or more has not continued for 5 seconds or longer (NO in step S33), the process ends. If it is determined that a current of 10 mA or more continues for 5 seconds or longer (YES in step S33), it is determined that a ground fault has occurred in the switching unit 16 (step S34). An alarm signal for notifying the system of this fact is output.

  Thus, when a ground fault occurs on any of the solar panel 11 side, the load 12 side, or the switching unit 16, the operator is notified that the ground fault has occurred after specifying the ground fault position. It can be done.

  In this way, in the insulation monitoring device for the charge / discharge system according to the present embodiment, the DC current sensor 14 detects the currents In and Ip flowing in the electric wires L1 and L2 connected to the positive terminal and the negative terminal of the battery 15. If the detected current is 10 mA and this current continues to flow for 5 seconds or more, it is determined that a ground fault has occurred at any point in the charge / discharge system. Furthermore, it is possible to specify whether a ground fault occurs on the solar panel 11 side, the load 12 side, or the switching unit 16 based on the connection state of the switches SW1 and SW2.

  Therefore, when a ground fault occurs, the location where the ground fault occurs can be identified and notified to the operator, and when a ground fault occurs, this problem can be dealt with immediately. In addition, since the ground fault state of the entire charging / discharging system can be monitored by the single current sensor 14 and the control device 13, the entire system can be reduced in size and cost.

  In the above-described embodiment, the illuminance sensor is used to set the charging state during the daytime and the discharging state at night. However, it is also possible to switch between charging and discharging at the current time without using the illuminance sensor. is there. For example, it is possible to switch to the charging state at 6:00 am and switch to the discharging state at 6:00 pm.

  In the above-described embodiment, the solar panel 11 has been described as an example of the DC power source. However, the present invention is not limited to this, and power generated using natural energy is used as DC power. The present invention can be applied to a DC power source that outputs. For example, it is also possible to use a power supply (DC power supply) that converts AC power generated by wind power generation into DC power and outputs it.

  Furthermore, in the above-described embodiment, an example in which the charging state and the discharging state are switched using the switching unit 16 has been described. However, the solar panel 11 and the battery 15 are directly connected using electric wires, and the battery 15 and the load 12 are connected. Are connected directly using electric wires, and are configured to detect a ground fault occurring on the solar panel 11 side or a ground fault occurring on the load 12 side by detecting a direct current flowing through each electric wire. May be.

  Further, in the above-described embodiment, the switching unit 16 can be selected in three positions: a charging state (connection of a1 and b1), a discharging state (connection of a3 and b3), and a neutral state (connection of a2 and b2). Although the example to do was demonstrated, if it is not necessary to monitor the insulation state of the switching part 16, it can also be set as the structure switched to either one of two states, a charge state and a discharge state.

  Furthermore, in the above-described embodiment, the ground fault is detected based on the currents Ip and In flowing in the electric wire L2 connected to the plus terminal of the battery 15 and the electric wire L1 connected to the minus terminal. It is also possible to provide a configuration in which a grounding current I4 of the battery 15 is detected by providing a grounding wire between 15 and the ground and providing a current sensor on the grounding wire. In this case, it can be detected that the ground fault current I4 has flowed through the battery 15 itself, and a ground fault can be detected in a wider range.

  As mentioned above, although the insulation monitoring apparatus of the charging / discharging system of this invention was demonstrated based on embodiment of illustration, this invention is not limited to this, The structure of each part is arbitrary structures which have the same function. Can be replaced with something.

  The present invention can be used to monitor the insulation state of a charge / discharge system that stores electric power in a battery and drives a load.

11 Solar panel (DC power supply)
12 Load 13 Control device 14 Current sensor (current detection means)
15 Battery (electric storage means)
16 switching part (switching means)
21 CPU
22 LPF
23 Amplifier 24 Excitation output section 25 LPF
26 Synchronous detection unit 27 Detection signal input unit 31 Excitation coil 32 Detection coil

Claims (5)

A DC power supply that outputs generated power as DC power, a storage means that stores the DC power output from the DC power supply, and a charge / discharge system that includes a load that operates when the power stored in the storage means is supplied In the insulation monitoring device for monitoring the insulation state,
DC current detection means for detecting a current flowing in at least one of an electric wire connecting the DC power source and the power storage means, and an electric wire connecting the power storage means and the load;
Insulation state monitoring means for monitoring an insulation state of at least one of the DC power supply and the load based on the current detected by the DC current detection means;
An alarm means for outputting an alarm signal when the insulation monitoring means determines that the insulation state of the DC power supply or the load is defective;
An insulation monitoring device for a charge / discharge system, comprising:   The battery further includes switching means for selectively connecting the connection terminal of the power storage means to the DC power supply or the load, and the DC current detection means is provided on the electric wire connecting the switching means and the connection terminal. The insulation monitoring apparatus for a charge / discharge system according to claim 1.   The switching means further comprises switching means for connecting the connection terminal of the power storage means to any one of the DC power supply, the load, and a neutral position not connected to any of the DC power supply and the load, The insulation monitoring device for a charge / discharge system according to claim 1, wherein the direct current detection means is provided on an electric wire connecting the connection terminal and the connection terminal.   The insulation state monitoring means determines an insulation state of the switching means based on a current detected by the DC current detection means when the switching means is connected to the neutral position. The insulation monitoring apparatus for a charge / discharge system according to claim 3.   The DC power source is a solar panel, and the switching means is connected between the solar panel and the power storage means, or connected between the load and the power storage means, depending on the illuminance near the solar panel. Any one of these is selected, The insulation monitoring apparatus of the charging / discharging system of any one of Claims 1-4 characterized by the above-mentioned.

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