JP2016181969A - System controller for dispersion type power source, system control method for dispersion type power source, and power conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system controller for dispersion type power source, capable of suppressing inverse load flow electric power without causing a major modification or a cost increase in a power conditioner or the like.SOLUTION: The system controller SC for dispersion type power source, connected with a plurality of power conditioners PCS interconnecting with a system through a communication wire, includes a storage part in which a power generation schedule with electric power and/or timing capable of an inverse load flow set is stored in the system; an inverse load flow power command part which transmits a power command value capable of an inverse load flow on the basis of the power generation schedule stored in the storage part to each power conditioner PCS through the communication line.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a distributed power system control apparatus, a distributed power system control method, and a power conditioner.

  Distributed power sources such as solar power generators, wind power generators, and fuel cell devices are connected to commercial power systems such as three-phase three-wire systems and single-phase three-wire systems. It is equipped with a power conditioner that converts DC generated power into AC power so as to suit the system.

  The power conditioner includes a DC / DC converter that adjusts a DC voltage generated by a distributed power source to a predetermined DC voltage value, an inverter that converts DC power output from the DC / DC converter into AC power, An LC filter that removes high-frequency components from the output is provided.

  According to Article 26, etc. of the Electric Power Business Law, when such a distributed power source is connected to a low voltage distribution system, the voltage at the receiving point of the low voltage consumer equipment is 101 ± 6V with respect to the standard voltage 100V, and the standard voltage 200V. In contrast, it is specified to maintain an appropriate value within 202 ± 20V.

  However, when multiple distributed power sources are connected to the low-voltage distribution system and a reverse power flow occurs where the active power flows from each distributed power source to the system power source side, the voltage at the receiving point of each low-voltage consumer facility increases, and There is a risk of deviating from the value.

  In Patent Document 1, in a low-voltage distribution system to which a plurality of distributed power sources that generate reverse power flow are connected, by effectively utilizing the power generation capability of each distributed power source while not exceeding the upper limit value of a specified voltage, For the purpose of providing a distribution system capable of increasing the total output of active power across a plurality of distributed power sources in the same bank, the distribution path from the power receiving point to the secondary terminal of the pole transformer A configuration is disclosed in which the impedance is calculated and the magnitude of active power or reactive power output from an inverter provided in each distributed power source is adjusted according to the calculated impedance.

  In Patent Document 2, as a method of controlling a power conditioner in a solar power generation system that can suppress voltage fluctuations of the power system while suppressing deterioration of the power factor and maintaining high conversion efficiency, the grid connection point voltage of the power system and Obtain the voltage difference from the detection voltage at the connection point to the power system, and calculate the line constant from the power system connection point to the connection point of the power system based on this voltage difference, the detection voltage at the connection point, and the current flowing into the power system. In addition, the active power and reactive power of the inverter are obtained, the voltage drop value is obtained from the active power and reactive power of the power conditioner and the line constant, and the reactive power of the power conditioner is set so that the voltage drop value is eliminated. A configuration to control is disclosed.

JP 2010-213542 A JP 2011-55678 A

  However, if distributed power sources such as photovoltaic power generation devices become widespread and the number of distributed power sources that can be linked to the commercial power system increases, the power supply will become overpowered even in the daytime when power demand is high, and the capacity that can be received by the transmission line For example, each power conditioner linked to the commercial power system is required to have a function to suppress and control reverse power flow at a specified output in a specified time zone.

  The conventional system voltage rise suppression control cannot cope with such output suppression, and it is necessary to newly incorporate such a function in each power conditioner.

  However, in order to provide such a function in each power conditioner, the communication device that receives the reverse flow power suppression information from the outside, or the reverse flow power is controlled based on the suppression information received by the communication device There was a problem that it was necessary to provide a control device, which required a significant design change and increased product costs.

In view of the above-described problems, an object of the present invention is to provide a system controller for a distributed power source that can suppress reverse power flow without significantly remodeling the power conditioner or increasing the cost, and a distributed power source. A system control method and a power conditioner are provided.

  In order to achieve the above object, a first characteristic configuration of a system controller for a distributed power supply according to the present invention is a plurality of power conditions connected to a system as described in claim 1 of the claims. A distributed power supply system controller connected through a communication line, a storage unit storing a power generation schedule in which power and / or time that can be reversely flowed in the system is stored, and the storage unit And a reverse flow power command unit that transmits a power command value capable of reverse flow based on the stored power generation schedule to each power conditioner via the communication line.

  The system controller of the distributed power source that controls a plurality of power conditioners via the communication line outputs the power command value to each power conditioner, so that the power command value received by each power conditioner is reversed. Adjustable to tidal power. In other words, it is not necessary to input a power generation schedule in which power and / or timing capable of reverse flow is set in each power conditioner, and it is not necessary to provide a dedicated communication device or control device for that purpose.

  In the second feature configuration, as described in claim 2, in addition to the first feature configuration described above, the power generation schedule defines a power upper limit value capable of reverse flow and a time zone thereof, and the reverse flow When changing the power upper limit value based on the power generation schedule, the power command unit is configured to transmit the power command value calculated so that the reverse power flow changes with a predetermined slope to each power conditioner. In the point.

  When the system control device switches the reverse power flow of each power conditioner at a time based on the power generation schedule, there is a risk that the system voltage and the like will fluctuate greatly. However, when a power command value calculated so that the reverse power flow changes with a predetermined slope is sent from the system controller to each power conditioner, each power conditioner individually receives the reverse power flow according to the power command value. Can be adjusted. At this time, it is only necessary to add a function to the control unit so as to adjust the reverse power flow to the power command value input via the communication line.

  As described in claim 3, the third feature configuration is connected to the system management server via a communication line in addition to the first or second feature configuration described above, and is received from the system management server. The power generation schedule is configured to be stored in the storage unit.

  A reverse power flow suppression schedule is transmitted from the system management server to the system control device via the communication line and stored in the storage unit of the system control device. Based on the suppression schedule, each reverse power flow command unit of the system control device The power command value is transmitted to the inverter. Therefore, it is not necessary to provide each power conditioner with a communication device for transmitting a reverse flow power suppression schedule from the system management server.

  The first characteristic configuration of the distributed power supply system control method according to the present invention is the distributed power supply system for controlling a plurality of power conditioners linked to the system via communication lines as described in claim 4. A power generation schedule reading step of reading a power generation schedule from a storage unit storing a power generation schedule in which power and / or timing that can be reversely flowed in the system is set, and the power generation schedule read step. A reverse flow power command step of transmitting a power command value capable of reverse flow based on a power generation schedule to each power conditioner via the communication line.

  In the second characteristic configuration, as described in claim 5, in addition to the first characteristic configuration described above, the power generation schedule defines a power upper limit value capable of reverse flow and a time zone thereof, and the reverse flow The power command step is configured to transmit, to each power conditioner, a power command value calculated so that the reverse power flow changes with a predetermined slope when the power upper limit value is changed based on the power generation schedule. In the point.

  A first characteristic configuration of the power conditioner according to the present invention is the communication line connected to the system controller of the distributed power source having any one of the first to third characteristic configurations described above. A power conditioner connected via a storage unit for storing a power command value transmitted from the system control device, and a reverse power flow so as not to exceed a power command value stored in the storage unit. The output control unit for adjustment is provided.

  As described above, according to the present invention, the distributed power supply system control device and the distributed power supply system control capable of suppressing the reverse power flow without causing significant remodeling or cost increase in the power conditioner or the like. A method and a power conditioner can be provided.

System configuration diagram of a distributed power source in which a system controller and multiple power conditioners are network-connected (A) is a block configuration diagram of a power conditioner, (b) a block configuration diagram of a system controller of a distributed power supply 1 is a system configuration diagram of a distributed power source in which the system control device of FIG. 1 is incorporated in one power conditioner. System configuration diagram of a distributed power source in which system control devices provided for a plurality of system lines are connected to a system management server via a common gateway

  Hereinafter, a distributed power system controller, a distributed power system control method, and a power conditioner according to the present invention will be described with reference to the drawings.

  FIG. 2A shows a distributed power source including the solar power generation device 1 and the power conditioner PCS. The power conditioner PCS is connected to the system power supply 100 via the interconnection relay Ry. In the following description, the case where the power generation device connected to the power conditioner PC is the solar power generation device 1 will be described, but the present invention is applied to other power generation devices such as a wind power generation device and a fuel cell. can do.

  The power conditioner PCS includes a DC / DC converter 2 that converts a DC output voltage of the photovoltaic power generator 1 into a predetermined DC voltage value, and an inverter 3 that converts DC power output from the DC / DC converter 2 into AC power. And an inverter control unit 4 that performs PWM control of the inverter 3, an LC filter 5 that removes harmonics from the output of the inverter 3, and the like.

  The inverter control unit 4 is configured to perform PWM control of the inverter 3 based on the system voltage and current detected by the system voltage / current sensor 6 so as to be connected to the system. Further, a storage unit for storing the power command value input via the communication unit C2 is provided, and an output for outputting a suppression value of the reverse power flow to the inverter control unit 4 based on the power command value stored in the storage unit A suppression unit 10 is provided.

  The inverter control unit 4 and the output suppression unit 10 constitute output control units 4 and 10 that adjust the reverse flow power so as not to exceed the power command value stored in the storage unit. For example, when the power command value is set to 50% of the rated output, the output control unit is configured to control the power output from the inverter 3 and flowing backward to the system to be 50% of the rated output. ing.

  The output of the system voltage / current sensor 6 is input to the isolated operation detection unit 7 in addition to the inverter control unit 4, and whether or not it is in the isolated operation state based on an active method such as a single slip mode frequency shift method or a reactive power fluctuation method. Is detected.

  When the isolated operation detection unit 7 calculates the fluctuation component given to the output current phase with respect to the system voltage and current detected by the system voltage / current sensor 6 and outputs the fluctuation component to the inverter control unit 4, the inverter control unit 4 causes the inverter 3 to operate. The AC power, which is controlled and added with the fluctuation component for detecting the isolated operation, is output to the system via the system relay Ry. The islanding operation detection unit 7 determines whether or not the islanding operation state is in the islanding operation state according to the degree of fluctuation of the system voltage / current detected by the system voltage / current sensor 6 at this time.

  When it is determined by the islanding detection unit 7 that the vehicle is in the islanding operation state, the grid connection Ry is disconnected by the grid connection protection unit 8 and the power conditioner PCS is disconnected from the grid power source. Stopped.

  The above-described power conditioner PCS is connected to the same system power supply, and the synchronization signal generation / processing unit 9 is provided so that a network configuration can be realized in which the system control device is centrally controlled via the communication unit C2. It has more.

  When the power conditioner PCS functions as a synchronization master, the synchronization signal generation / processing unit 9 is configured to output a synchronization signal, which is a square wave having a frequency synchronized with the system power supply frequency, to the slave-side power conditioner PCS. When the power conditioner PCS functions as a slave, a synchronization signal output from the power conditioner PCS on the synchronization master side is input, and interconnection control with the system power supply is performed in synchronization with the synchronization signal. It is configured as follows.

  The interconnection control used in the present embodiment is a control in which the inverter 3 is driven so that the power conditioner PCS functioning as a slave closes the interconnection relay Ry and is connected to the system power supply when a synchronization signal is input. , Control for changing the phase of the output current in the same direction in synchronization with the synchronization signal for detection of isolated operation, and control for opening the connection relay Ry and disconnecting the inverter 3 when the synchronization signal stops, When the power conditioner PCS functioning as a synchronization master receives an interconnection command with the system power supply from the system control device, it refers to a control that generates and outputs a synchronization signal.

  Each functional block of the inverter control unit 4, the isolated operation detection unit 7, the grid connection protection unit 8, the synchronization signal generation / processing unit 9, the output suppression unit 10, the output suppression control units 4 and 10, and the communication unit C2 is a microcomputer. And hardware such as a storage unit (memory) and an input / output device, and software such as a control program executed by the microcomputer and stored in the memory.

  FIG. 2B shows a functional block configuration of the system control device SC. The system controller SC manages the control constant setting unit 11 for setting the control constant of each power conditioner PCS, the start / stop control unit 12 for starting or stopping each power conditioner PCS, and the history of each power conditioner PCS. The history management unit 13, the reverse flow power command unit 14, the storage unit 16 that stores management information including control constants and reverse flow power command values necessary for each unit, and communicates with each power conditioner PCS and through the gateway The communication part C1 which communicates with the system | strain management server 20 which manages the state of a commercial system | strain is provided.

  The control constants set by the control constant setting unit 11 are various set values such as an AC overvoltage (OVR) detection threshold used in each power conditioner PCS.

  Similarly to the control unit of the power conditioner PCS, each functional block constituting the system control device SC is executed by the microcomputer and hardware such as a storage unit (memory) and an input / output device, and is executed by the microcomputer and stored in the memory. It consists of software such as a control program.

  The communication units C1 and C2 are interfaces for performing two-wire half-duplex serial communication based on the RS485 standard or the like, and each polling from the system controller SC functioning as a master station is a power condition that is a slave station. Data is transmitted / received to / from each other by a polling / selecting method to which the PCS responds. Therefore, a unique ID is set in advance for each power conditioner PCS.

  Each ID is set in the header part constituting the frame data transmitted from the system controller SC, and commands such as start / stop / voltage suppression commands are set in the data part. When the data part is null, it becomes a polling command. When each power conditioner PCS receives a polling command including an ID set for itself, it writes status information indicating its own state in the data portion and returns it. In the status information, time information, a status code of normal or abnormal, and an abnormal code are transmitted in the case of abnormality, and a subcode such as stop or activation is transmitted in the case of normality.

  When the administrator operates various operation switches provided in the operation unit of the system control device SC, the overall control for each power conditioner PCS is executed. For example, when a start switch is operated, a start command is transmitted to each power conditioner PCS to start overall control, and when a stop switch is operated, a stop command is transmitted to each power conditioner PCS. Overall control ends.

  In FIG. 1 (a), one power conditioner M-PCS functioning as a synchronization master and seven power conditioners S-PCS functioning as slaves are connected to the system control device SC via communication lines (RS485). Configurations connected via are shown.

  A gateway is connected to the communication line (RS485), and is configured to be able to communicate with the power system management server 20 via a wireless communication medium such as WiFi or a wired communication medium.

  Further, a monitor PC is connected to the communication line (RS485), and information on each power conditioner PCS managed by the system control device SC is transmitted via a monitor PC to a remote administrator's terminal and a wireless or wired communication medium. It is configured to be connectable via

  A synchronization signal output from the synchronization signal generation / processing unit 9 (see FIG. 2A) of the power conditioner M-PCS is input to each power conditioner S-PCS via the synchronization signal line, and each power conditioner M-PCS and S-PCS are connected to the system line via the interconnection relay Ry (see FIG. 3A).

  In the synchronization signal generation / processing unit 9 of the power conditioner M-PCS, a square wave having the same frequency synchronized with the frequency of the system voltage is generated and input to the synchronization signal generation / processing unit 9 of each power conditioner S-PCS. The

  When the administrator operates a start switch provided in the operation unit of the system controller SC, a start command is transmitted from the system controller SC to each power conditioner M-PCS, S-PCS, and each power conditioner M-PCS, S-PCS is activated.

  The power conditioner M-PCS functioning as a synchronization master closes the interconnection relay Ry and controls the inverter 3 so that interconnection can be performed based on the system voltage and current detected by the system voltage / current sensor 6. Then, a synchronization signal is generated and output to the synchronization signal line.

  When the synchronization signal is input, the power conditioner S-PCS functioning as a slave closes the interconnection relay Ry so that the interconnection can be established based on the system voltage and current detected by the system voltage / current sensor 6. The inverter 3 is controlled.

  The isolated operation detection unit 7 provided in each of the power conditioners M-PCS and S-PCS detects whether or not the operation is in an isolated operation by controlling the output current to fluctuate in the same direction in synchronization with the synchronization signal. To do.

  The power conditioner S-PCS determined to be in the isolated operation state by the isolated operation detection unit 7 is disconnected or stopped, and the factor and the disconnected or stopped state are transmitted to the system controller SC. The system control device SC stores the information transmitted from the power conditioner S-PCS in the storage unit 16 and outputs it to the monitor PC.

  In the storage unit 16 of the system control device SC, a storage area for storing the power generation schedule transmitted from the power system management server 20 via the gateway is set. The reverse power flow power command unit 14 stores the power generation schedule transmitted from the system management server 20 in the storage unit 16 and outputs a power command value capable of reverse power flow to each power conditioner PCS based on the power generation schedule. It is configured.

  The power generation schedule is a power generation schedule that is determined by the power company that manages the grid, and that sets the power and timing that allow reverse power flow to the grid, specifically the maximum power and time zone. For example, a power conditioner PCS is installed. It is a power generation calendar that is set for each region and stipulates the maximum power that can be reversed in each time zone.

  The “power capable of reverse flow” defined in the present invention may be a power value itself or a numerical value expressed by a ratio (power ratio) to a rated capacity. When expressed in terms of power ratio, it is not necessary to consider individual power conditioners with different rated capacities. Similarly, the “power command value” may be the power value itself, or may be a numerical value represented by a ratio (power ratio) to the rated capacity.

  When the reverse power flow command unit 14 reaches the time specified in the power generation schedule and transmits the maximum power as a command value to each power conditioner PCS, the output suppression unit 10 of each power conditioner PCS that has received the command value. Is output to the inverter control unit 4, and the inverter control unit 4 suppresses the reverse power d power to the maximum power corresponding to the command value.

  Here, when the maximum power designated at the time designated in the power generation schedule is output as a command value from the reverse power flow command unit 14, the power conditioners respond all at once and the state of the system temporarily fluctuates greatly. There is a fear.

  Therefore, when changing the power upper limit value based on the power generation schedule, the reverse flow power command unit 14 calculates the power command value calculated so that the reverse flow power gradually changes at a predetermined slope for each power condition. Configured to transmit to the PCS.

  For example, when it is necessary to suppress the reverse flow power from 100% to 50% from time T1 to T2, the reverse flow power command unit 14 takes 100% to 50 over a predetermined time ΔT from time T1. A command value that gradually decreases every ΔT / n (n is a natural number) time so as to be gradually suppressed to% is output. The predetermined time ΔT is not particularly limited and is arbitrary, for example, a value from several minutes to ten and several minutes. This value may be configured to be transmitted from the system management server 20. ΔT / n is a value from several milliseconds to several seconds.

  Such a power generation schedule is set so that it can be updated daily by the electric power company based on the weather, etc., and the reverse power flow command unit 14 receives the power generation schedule stored in the storage unit 16 every time it receives a power generation schedule from the system management server 20. It is configured to store updates.

  In the distributed power supply system shown in FIG. 1, the example in which the system controller SC and the power conditioner PCS are configured as separate apparatuses has been described. However, even if the function as the system controller SC is incorporated in the power conditioner PCS. Good.

  FIG. 3 shows an example in which the system controller SC is incorporated in a power conditioner M-PCS that functions as a synchronization master, and the power conditioner M-PCS functions as a communication master station. .

  As shown in FIG. 4, a plurality of power conditioners PCS and a plurality of system control devices SC connected to the network are configured to share a power generation schedule received from the system management server 20 via the same gateway. Also good.

  The power generation schedule received from the system management server 20 is not limited as long as the power and / or time that can be reversely flowed is set in the system. For example, the power generation schedule may include only the maximum power that can be reversely flowed. The maximum possible power may be fixed, and the power generation schedule only for that time period may be used.

  In the above-described embodiment, the example in which the system control device SC and the system management server 20 are directly connected via the gateway has been described. However, the system control device SC and the server of the inverter of the power conditioner PCS are connected, The configuration may be such that the administrator's server and the system management server 20 are connected. In this case, there is no need to provide a monitor PC. The administrator means either the owner of the distributed power source or the manufacturer of the distributed power source.

  In the above-described embodiment, the mode in which the power conditioner M-PCS functioning as the synchronization master outputs a synchronization signal for detecting an independent operation has been described. However, such a mode is not adopted and each power conditioner is individually Alternatively, it may be configured to perform isolated operation detection.

  The system control device SC stores a power generation schedule in which power and / or time that can be reversely flowed in the system is stored, and a power command value that can be reversely flowed based on the power generation schedule stored in the storage unit. It is sufficient if each power conditioner is provided with a reverse power flow command unit that transmits via a communication line, and a single-function configuration that does not include other functions such as the history management unit described above may be used.

  As described above, the distributed power supply system control method according to the present invention is executed by the reverse power flow command unit 14 and stores a power generation schedule in which power and / or timing capable of reverse power flow are set in the system. A power generation schedule reading step for reading a power generation schedule from the power generation schedule, and a reverse power flow power command step for transmitting a power command value capable of reverse flow based on the power generation schedule read in the power generation schedule reading step to each power conditioner via a communication line And.

  The power generation schedule defines the upper power limit value and the time zone during which reverse power flow is possible, and the reverse power power command step ensures that the reverse power flow changes with a predetermined slope when changing the power upper power value based on the power generation schedule. The calculated power command value is configured to be transmitted to each power conditioner.

  The power conditioner according to the present invention includes a storage unit that stores a power command value transmitted from the system controller SC, and an output control that adjusts the reverse flow power so as not to exceed the power command value stored in the storage unit. Department.

  As described above, a plurality of embodiments of the distributed power system control apparatus, distributed power system control method, and power conditioner according to the present invention have been described. However, the above-described embodiments are merely examples of the present invention. Needless to say, the specific configuration and the like of each block can be changed and designed as appropriate within the scope of the effects of the invention.

1: Solar power generation device 2: DC / DC converter 3: Inverter 4: Inverter control unit 5: LC filter 6: System voltage / current sensor 7: Independent operation detection unit 8: System interconnection protection unit 9: Synchronization signal generation / Processing unit 10: Output suppression unit 14: Reverse power flow command unit C1, C2: Communication unit PCS: Power conditioner SC: System controller

Claims (6)

A system controller for a distributed power source in which a plurality of power conditioners connected to a system are connected via a communication line,
A storage unit storing a power generation schedule in which power and / or time that can be reversely flowed in the system is stored, and a power command value that can be reverse flowed based on the power generation schedule stored in the storage unit to each power conditioner A system controller for a distributed power source, comprising: a reverse power flow command unit for transmitting via the communication line.   The power generation schedule defines a power upper limit value and a time zone in which reverse power flow is possible, and when the power flow command unit changes the power power upper limit value based on the power generation schedule, the reverse power flow changes at a predetermined slope. The system controller for a distributed power supply according to claim 1, wherein the power command value calculated in such a manner is transmitted to each power conditioner.   3. The distributed power supply system control device according to claim 1, wherein the system control device is connected to a system management server via a communication line and configured to store the power generation schedule received from the system management server in the storage unit. A system control method for a distributed power source that controls a plurality of power conditioners linked to a grid via a communication line,
A power generation schedule reading step of reading a power generation schedule from a storage unit storing a power generation schedule in which power and / or time that can be reversely flowed in the system is stored;
A distributed power source comprising: a reverse power flow command step for transmitting a power command value capable of reverse flow based on the power generation schedule read in the power generation schedule read step to each power conditioner via the communication line. System control method.   The power generation schedule defines a power upper limit value that allows reverse flow and its time zone, and the reverse flow power command step changes the reverse power flow at a predetermined slope when changing the power upper limit value based on the power generation schedule. 5. The system control method for a distributed power supply according to claim 4, wherein the power command value calculated so as to be transmitted is transmitted to each power conditioner. A power conditioner connected to the system controller of the distributed power source according to any one of claims 1 to 3 via the communication line,
The power conditioner provided with the memory | storage part which stores the electric power command value transmitted from the said system control apparatus, and the output control part which adjusts reverse flow electric power so that the electric power command value memorize | stored in the said memory | storage part may not be exceeded.

Images