Reactive Power Demand Response System

Abstract

To provide a reactive power demand response system, capable of controlling system voltage in a power distribution system.SOLUTION: A reactive power demand response system 1 includes a computer (a fourth ERC4E) controlling each of a plurality of building multi air conditioners BAs so as to supply reactive power, to a power distribution system ES, by the building multi air conditioners BAs. The fourth ERC4E proportionally distributes, to each building multi air conditioner BA, the reactive power based on mathematical programming for room temperature deviation and allocates target reactive power in each building multi air conditioner BA. The mathematical programming is a least-squares method to determine proportional distribution coefficients for each building multi air conditioner BA with respect to the reactive power such that the total sum of squares of each room temperature deviation is minimized.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a reactive power demand response system capable of controlling reactive power in an electric power system (electric power distribution system). [Background technology]

[0002] Patent Publication No. 6572113 (Patent Document 1) discloses a power consumption control device, and in paragraph

[0019] it states, "Furthermore, power consumption may be active power only, reactive power only, or apparent power (the sum of active power and reactive power). Here, we will explain the case where power consumption is apparent power (VA). Note that reactive power is not consumed, but here, the reactive power used by electrical equipment is included in the term power consumption." In this embodiment of the power consumption control device, control of reactive power alone is not disclosed at all. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6572113 Summary of the Invention [Problem to be solved by the invention]

[0004] One of the main objects of the present invention is to provide a reactive power demand response system capable of controlling the system voltage in a power distribution system. [Means for solving the problem]

[0005] In order to achieve the above object, the invention described in claim 1 provides a power distribution system including a computer that controls a plurality of building multi-air conditioners so that reactive power is supplied to a power distribution system by the building multi-air conditioners. The computer allocates the reactive power to each of the building multi-air conditioners based on a mathematical programming method related to room temperature deviation, and allocates target reactive power to each of the building multi-air conditioners. It is characterized by the following. Claim 2The invention described in is characterized in that, in the above invention, the mathematical programming is a least squares method that determines an apportionment proportional coefficient for each building multi-air conditioner for the reactive power so that the sum of the squares of each room temperature deviation is minimized, or determines an apportioned reactive power for each building multi-air conditioner equivalent to the value obtained by multiplying the reactive power by the apportionment proportional coefficient. Claim 3 The invention described in is characterized in that, in the above invention, the building multi-air conditioner has a compressor motor, an inverter connected to the compressor motor, and an active converter that adjusts the power to the inverter. Claim 4 The invention described in is characterized in that, in the above invention, the active converter generates reactive power related to the target reactive power allocated to the building multi-air conditioner by controlling the active power for air conditioning of the building multi-air conditioner to which it belongs. [Effects of the Invention]

[0006] One of the main advantages of the present invention is that it provides a reactive power demand response system capable of controlling the system voltage in a power distribution system. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a block diagram of a reactive power demand response system of the present invention. [Figure 2] FIG. 2 is a block diagram of an outdoor unit in the building multi-air conditioning system of FIG. 1. [Figure 3] 2 is a flowchart showing an example of the operation of the reactive power demand response system of FIG. 1. [Figure 4] 3 is a graph showing the principle of reactive power control by the active converter of FIG. 2. [Figure 5] 2A is a graph showing the change over time in active power Pb AC, reactive power Qb AC, and room temperature deviation Tb SA in the reactive power demand response system of FIG. 1 (A) and (B). DETAILED DESCRIPTION OF THE INVENTION

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings, in which: FIG.

[0009] [Local voltage fluctuations in the power distribution system ES, etc.] FIG. 1 is a block diagram of a reactive power demand response system 1 installed in a power distribution system ES. The local voltage fluctuations in the power distribution system ES, which are relevant to the reactive power demand response system 1, will be explained first.

[0010] Recently, DERs (Distributed Energy Resources), which can act as both loads and sources of power, such as photovoltaic power generation systems D1, battery storage systems D2, and rapid chargers D3 for electric vehicles (EVs), are being connected to the power distribution system ES. In the near future, a large number of DERs will be connected within a relatively small area AR, typically within a radius of a few kilometers. That is, there will be a plurality of businesses in the distribution system ES that have any number of photovoltaic power generation systems D1, which may be one or more. Also, there will be a plurality of businesses in the distribution system ES that have any number of storage battery systems D2, which may be one or more. The storage battery systems D2 are BESSs (Battery Energy Storage Systems). Furthermore, there will be a plurality of businesses in the distribution system ES that have any number of quick chargers D3, which may be one or more. Note that the DERs are not limited to photovoltaic power generation systems D1, storage battery systems D2, and quick chargers D3. In this case, localized voltage fluctuations are likely to occur in the power distribution system ES. For example, fluctuations in solar radiation change the amount of power generated by the photovoltaic power generation system D1, causing voltage fluctuations in the photovoltaic power generation system D1. Switching of the storage battery system D2 between a charging (load) state and a discharging (power supply) state causes voltage fluctuations in the storage battery system D2. Furthermore, charging EVs causes voltage fluctuations that place a large load on the rapid charger D3 for about 30 minutes per vehicle. In addition, reverse power flows in the power distribution system ES also occur frequently and in complex ways.

[0011] Such voltage fluctuations occur locally from moment to moment in the power distribution system ES. Furthermore, the smoothing effect of DERs belonging to a wide area cannot be expected to be very strong against such voltage fluctuations. Furthermore, in the case of the sending voltage control of the distribution substation TS and the voltage adjustment equipment at the fixed point, since the voltage fluctuation points change constantly, it is difficult to respond to such voltage fluctuations. On the other hand, it is possible to deal with such voltage fluctuations by installing new dedicated voltage adjusting devices at many points throughout the power distribution system ES and keeping them on standby. However, this would entail enormous costs, including the costs of manufacturing, installing, and maintaining each voltage adjusting device.

[0012] In contrast to these viewpoints, the reactive power demand response system 1 uses a group of consumer load equipment that is already widely distributed in the distribution system ES within the area AR and has a scale equal to or greater than a predetermined level, and by controlling the reactive power locally in a relatively short period of time for one or more load equipment belonging to the load equipment group, it becomes possible to respond to such voltage fluctuations at low cost. In the reactive power demand response system 1, DERs are controlled (managed) to suppress voltage fluctuations by controlling reactive power. Therefore, the reactive power demand response system 1 is a type of DERMS (DER Management System) related to smart grid technology. In addition, the reactive power demand response system 1 increases or decreases (Response) reactive power (unit: var) depending on the situation (Demand), and is therefore appropriately referred to as VarDR in this application. Such load equipment is widespread and therefore normally performs its intended function, and also has the ability to temporarily prioritize power source power factor control and control reactive power in order to contribute to the stability of the power distribution system ES. In other words, the load equipment can control reactive power without excessively impairing the intended function that led to its widespread use, and is capable of both intended function and reactive power control. An example of such load equipment is a building air conditioning system. A building air conditioning system is generally called a building multi-air conditioner BA, and is a collective equipment of multiple indoor units AN. Currently, building multi-air conditioners BA are used in many small and medium-sized commercial buildings such as office buildings in urban areas. In a power distribution system ES, there are multiple consumers that have any number of building multi-air conditioners BA, one or more.

[0013] [Building multi-air conditioner BA, etc.] The primary function of the building multi-air conditioner BA is room temperature control. The building multi-air conditioner BA has an outdoor unit OU and a plurality of indoor units AN connected thereto. Recently, as a countermeasure against harmonics in the power distribution system ES, it has become common to initially install an active converter AC in the outdoor unit OU of a building multi-air conditioner BA, or to retrofit an active converter AC as an accessory device. Active converter ACs are also called active filters or PMW converters.

[0014] FIG. 2 is a block diagram of the outdoor unit OU including the active converter AC. The active converter AC is connected to a 200V (volt) power distribution system ES to obtain power. The active converter AC is placed between the power distribution system ES and an inverter IN built into the outdoor unit, which serves as an inverter connected to the compressor motor CM of the outdoor unit OU of the building multi-air conditioner BA. The compressor motor CM, the outdoor unit built-in inverter IN, and the active converter AC are installed for each consumer, the number of which depends on the size of the building multi-air conditioner BA. Each active converter AC has a reactor RA, a bridge-type switching element BS, a diode DI, a resistor RS, a smoothing capacitor SC, a power supply voltage phase detection circuit PP, and a converter control circuit CC.

[0015] The reactor RA is arranged between the power distribution system ES and the bridge-type switching element BS. The bridge-type switching element BS corresponds to a three-phase power supply and has six pairs of diodes and transistors. The bridge-type switching element BS is connected to the outdoor unit's built-in inverter IN by two wires. The diode DI is inserted in series with one line between the bridge-type switching element BS and the outdoor unit built-in inverter IN. The resistor RS is connected in parallel with the diode DI. The smoothing capacitor SC is inserted in parallel with the two lines between the bridge-type switching element BS and the outdoor unit built-in inverter IN.

[0016] The power supply voltage phase detection circuit PP is a circuit that detects the voltage and phase of the power supply. More specifically, the power supply voltage phase detection circuit PP detects the voltage and phase between the reactor RE and the power distribution system ES. The converter control circuit CC is connected to the power supply voltage phase detection circuit PP. The converter control circuit CC controls the bridge-type switching element BS. More specifically, the converter control circuit CC controls the switching timing of each diode of the bridge-type switching element BS to convert at least one of the magnitude and phase of the voltage applied to the outdoor unit's built-in inverter IN into a desired one from at least one of the magnitude and phase of the power supply voltage. The minimum switching time is, for example, 50 μs (microseconds), and the converter control circuit CC can switch the current every minimum switching time. The converter control circuit CC is becoming increasingly popular as a countermeasure against harmonics, i.e., to prevent harmonics from being applied to the outdoor unit's built-in inverter IN and disrupting its operation, and therefore performs three-phase full-wave rectification using PMW control. On the other hand, as described above, the converter control circuit CC can convert at least one of the magnitude and phase of the power supply voltage to the desired one, and by rewriting (including adding) the software (program) of the converter control circuit CC, it becomes possible to perform three-phase full-wave rectification while contributing to the control of reactive power in the distribution system ES. Three-phase full-wave rectification contributes to stable operation of the compressor motor CM via the outdoor unit's built-in inverter IN, and contributes to stable operation of the building multi-air conditioner BA and contributes to room temperature control.Therefore, the converter control circuit CC, whose software has been modified, performs coordinated control of room temperature control to perform its original function, and reactive power control to suppress local voltage fluctuations in the distribution system ES. Each active converter AC regulates the power to the outdoor unit's built-in inverter IN.

[0017] In order to control reactive power, it is conceivable that the power factor of the AC input can be freely and precisely controlled in the power supply section of the building multi-air conditioner BA in order to inject and extract not only active power from the power distribution system ES but also reactive power. If a problematic location occurs in the power distribution system ES where voltage fluctuates locally for a short period of time, the reactive power demand response system 1 flexibly selects one or more building multi-air conditioners BA of a consumer receiving power from the adjacent area, thereby controlling the local distribution voltage problematic location, which moves from moment to moment in the power distribution system ES, so that the problem is suppressed.

[0018] [Configuration of reactive power demand response system 1] The reactive power demand response system 1 includes a DERMS server DS, a solar power generation intermediation server PM, a battery system intermediation server BM, a rapid charger intermediation server EM, a VarDR server VS, a first ERC1E attached to the solar power generation D1, a second ERC2E attached to the battery system D2, a third ERC3E attached to the rapid charger D3, and a fourth ERC4E attached to the building multi-air conditioner BA. Various "servers" are server computers, each equipped with a control unit (e.g., a CPU), a storage unit (e.g., a memory), an input unit (e.g., a keyboard), an output unit (e.g., a monitor), and a communication unit (e.g., an interface). At least one of the first ERC1E to the third ERC3E does not have to be included in the components of the reactive power demand response system 1.

[0019] The DERMS server DS is installed in the management area (for example, the power distribution system control center) of the power transmission organization PS. The DERMS server DS is connected to the photovoltaic power generation intermediation server PM, the battery system intermediation server BM, and the quick charger intermediation server EM via the Internet NE so as to be able to communicate control parameters CP, etc. The DERMS server DS is also connected to the VarDR server VS so as to be able to communicate Var control parameters VP, etc. The DERMS server DS may be connected to at least one of the photovoltaic power generation intermediation server PM, the battery system intermediation server BM, the quick charger intermediation server EM, and the VarDR server VS via a VPN (Virtual Private Network) or a dedicated network, etc. Furthermore, communication may be by at least one of wired and wireless means, and the same applies to the other communications described below.

[0020] The photovoltaic power generation intermediation server PM is connected to the first ERC 1E via the commercial closed communication network CN so as to be able to communicate control parameters CP, system voltage periodic reports VR, and the like. The photovoltaic power generation intermediation server PM is installed within the management area of ​​the photovoltaic power generation resource aggregator. The photovoltaic power generation intermediation server PM may be connected to the first ERC1E via the Internet NE, etc. The photovoltaic power generation intermediation server PM may also be installed within the management area of ​​the power transmission organization PS, etc. Furthermore, the photovoltaic power generation intermediation server PM may be omitted, and the DERMS server DS may communicate the control parameters CP and the system voltage periodic report VR directly with the first ERC1E.

[0021] The battery system intermediation server BM is connected to the second ERC2E via the commercial closed communication network CN so as to be able to communicate control parameters CP, system voltage periodic reports VR, etc. The battery system intermediation server BM is installed within the management area of ​​the battery system resource aggregator. The battery system intermediation server BM may be connected to the second ERC2E via the Internet NE, etc. The battery system intermediation server BM may also be installed within the management area of ​​the power transmission organization PS, etc. Furthermore, the battery system intermediation server BM may be omitted, and the DERMS server DS may communicate the control parameters CP and the system voltage periodic report VR directly with the second ERC2E.

[0022] The quick charger intermediation server EM is connected to the third ERC 3E via the commercial closed communication network CN so as to be able to communicate control parameters CP, system voltage periodic reports VR, and the like. The quick charger intermediation server EM is installed within the management area of ​​the quick charger resource aggregator. The quick charger intermediation server EM may be connected to the third ERC 3E via the Internet NE, etc. The quick charger intermediation server EM may also be installed within the management area of ​​the power transmission organization PS, etc. Furthermore, the quick charger intermediation server EM may be omitted, and the DERMS server DS may communicate the control parameters CP and system voltage periodic report VR directly with the third ERC 3E.

[0023] The VarDR server VS is connected to the fourth ERC 4E via the commercial closed communication network CN so as to be able to communicate the Var control parameters VP, the system voltage periodic report VR, and the like. The VarDR server VS is installed within the management domain of the VarDR resource aggregator. The VarDR server VS may be connected to the fourth ERC 4E via the Internet NE, etc. The VarDR server VS may also be installed within the management area of ​​the power transmission organization PS, etc. Furthermore, the VarDR server VS may be omitted, and the DERMS server DS may directly communicate the Var control parameters VP and the system voltage periodic report VR with the fourth ERC 4E. At least two of the various resource aggregators may be the same organization.

[0024] The first ERC1E controls the reactive power (unit: var) of the photovoltaic power generation D1 based on the received control parameters CP, etc., as is done in conventional DERMS. The first ERC1E can also control the active power (unit: W (watts)) as is done in conventional DERMS. The ERC is an Energy Resource Controller, and is a control device that controls one or more DER devices belonging to a predetermined area (such as a consumer's area). The first ERC1E has a DERMS communication function that communicates with the outside world from one or more DER devices (photovoltaic power generation D1), and an aggregation function that aggregates the voltage, active power, and reactive power of each DER device for that consumer's equipment. However, the photovoltaic power generation D1 is unevenly distributed in the power distribution system ES. Furthermore, the first ERC1E cannot appropriately control the reactive power depending on the power generation state of the photovoltaic power generation D1. The three photovoltaic power generation systems D1 are respectively connected to interconnection points GP1 to GP3 (voltages V1 to V3) of the power distribution system ES. Reactive power control in the three photovoltaic power generation systems D1 is performed by applying a reactive power control amount (reactive energy) ΔVar (kvar) to the voltages V1 to V3 of the corresponding interconnection points GP1 to GP3. Active power control in the three photovoltaic power generation systems D1 is performed by applying an active power control amount ΔW (kW (kilowatts)) to the voltages V1 to V3 of the corresponding interconnection points GP1 to GP3. The photovoltaic power generation systems D1 are, for example, on the scale of several hundred kW. Some or all of the photovoltaic power generation units D1 may belong to different businesses or may belong to the same business. The number of photovoltaic power generation units D1 and at least one of the interconnection points GP1 to GP3 to which they are connected are not limited to those described above. Also, the control of the active power of the photovoltaic power generation unit D1 may be omitted or may be performed by a different system.

[0025] The second ERC2E controls the reactive power in the battery system D2 based on the received control parameters CP, etc., as is done in conventional DERMS. The second ERC2E can also control active power, as is done in conventional DERMS. The second ERC1E has a DERMS communication function that allows one or more DER devices (battery system D2) to communicate with the outside, and an aggregation function that aggregates the voltage, active power, and reactive power of each DER device for the corresponding consumer equipment. However, the battery system D2 is unevenly distributed in the power distribution system ES. Furthermore, the second ERC2E cannot appropriately control reactive power depending on the state of the battery system D2, such as when the amount of energy stored in the battery system D2 falls below a predetermined level. The three storage battery systems D2 are connected to the distribution grid ES at interconnection points GP2, GP3, and GP20 (voltages V2, V3, and V 20 ) are connected to the respective grid points GP2, GP3, and GP20. The reactive power control amount ΔVar in the three battery storage systems D2 is calculated by controlling the voltages V2, V3, and V4 of the corresponding grid points GP2, GP3, and GP20. 20 The control of the active power in the three battery storage systems D2 is performed by applying the active power control amount ΔW to the voltages V2, V3, and V4 of the corresponding interconnection points GP2, GP3, and GP20. 20 The storage battery system D2 is, for example, on the scale of several tens of kW and is used as an emergency power source for the building. Some or all of the storage battery systems D2 may belong to different businesses or may belong to the same business. The number of storage battery systems D2 and at least one of interconnection points GP2, GP3, and GP20 to which they are connected are not limited to those described above. Also, the control of the active power of storage battery system D2 may be omitted or may be performed by another system.

[0026] The third ERC3E controls the reactive power in the quick charger D3 based on the received control parameters CP, etc., as is done in conventional DERMS. The third ERC3E is also capable of controlling active power, as is done in conventional DERMS. The third ERC3E has a DERMS communication function that allows one or more DER devices (quick charger D3) to communicate with the outside, as well as an aggregation function that aggregates the voltage, active power, and reactive power of each DER device for the corresponding consumer equipment. However, the quick chargers D3 are unevenly distributed in the power distribution system ES. Furthermore, the third ERC3E may not be able to appropriately control reactive power depending on the state of the quick charger D3, such as during quick charging. The three quick chargers D3 are connected to the distribution grid ES at points GP3, GP20, and GP39 (voltages V3 and V 20 ,V 39 ) are connected to the three quick chargers D3. The reactive power control amount ΔVar is calculated by controlling the voltages V3, V4 of the corresponding GP3, GP20, and GP39. 20 ,V 39 The control of the active power in the three quick chargers D3 is performed by applying the active power control amount ΔW to the voltages V3, V4 of the corresponding interconnection points GP3, GP20, and GP39. 20 ,V 39 The quick charger D3 has a capacity of several hundred kW, for example, enough to power about 10 EVs. Some or all of the rapid chargers D3 may belong to different operators or may belong to the same operator. The number of quick chargers D3 and at least one of the interconnection points GP3, GP20, and GP39 to which they are connected are not limited to those described above. Also, the control of the active power of quick charger D3 may be omitted or may be performed by a separate system.

[0027] The fourth ERC4E controls the reactive power in the building multi-air conditioner BA based on the received Var control parameter VP, etc. The fourth ERC4E can also control active power as is done in conventional DERMS. The fourth ERC4E has a DERMS communication function that allows one or more DER devices (building multi-air conditioners BA) to communicate with the outside world, as well as an aggregation function that aggregates the voltage, active power, and reactive power of each DER device for that customer's equipment. In addition, the fourth ERC4E has a function that allocates the reactive power control amount ΔVar allocated to the customer's equipment from the DERMS reactive power (the total amount of reactive power in a specific area within the area AR) to each DER device (building multi-air conditioner BA) as a reactive power control command (target reactive power). The building multi-air conditioners BA in many locations (for example, 23 locations) are connected to the distribution system ES at points GP20 and GP40 (voltage V 20 ,V 40 ) and so on. Building multi-air conditioners BA are more widespread in the power distribution system ES than other DER equipment (photovoltaic power generation D1, battery storage system D2, quick charger D3), and are originally widely installed throughout the entire power distribution system ES. Reactive power control in each building multi-air conditioner BA is performed by controlling the reactive power control amount ΔVar with the voltage V of the corresponding interconnection point GP20, GP40, etc. 20 ,V 40 The control of the active power in each building multi-air conditioner BA is performed by applying the active power control amount ΔW to the voltage V of the corresponding interconnection point GP20, GP40, etc. 20 ,V 40 This is done by acting on the following: Some or all of the building multi-air conditioners BA may belong to different customers, or may belong to the same customer. Hereinafter, the interconnection points GP1 to GP40 may be collectively referred to as interconnection points GP. Furthermore, at least one of the interconnection points GP1 to GP40 may be referred to as interconnection point GP. The numbers at the interconnection points GP1 to GP40 and their positions on FIG. 1 do not indicate the distance from the distribution substation TS, and do not suggest the spatial distribution of the points. The number of building multi-air conditioners BA and at least one of the interconnection points GP20, GP40, etc. to which they are connected are not limited to those described above. Also, control of the active power of the building multi-air conditioners BA may be omitted or may be performed by a separate system.

[0028] [Example of operation of reactive power demand response system 1 (reactive power allocation method)] The following describes an example of the operation of the reactive power demand response system 1. The example of the operation includes an example of a reactive power allocation method.

[0029] FIG. 3 is a flowchart relating to this operation example. The DERMS server DS determines whether reactive power control is necessary to stabilize the system voltage at each predetermined point in the distribution system ES based on various system voltage periodic reports VR (step S1), and if necessary (Yes), calculates the total amount of reactive power required at that point (step S2), and calculates the reactive power control amount ΔVar for each consumer facility by proportionally dividing the total amount of reactive power for the consumer facilities of adjacent building multi-air conditioners BA (step S3).Then, the DERMS server DS transmits a Var control parameter VP (reactive power control command) to the fourth ERC4E via the VarDR server VS based on the calculated reactive power control amount ΔVar (step S4). The DERMS server DS determines whether reactive power control is necessary, calculates the total amount of reactive power and each reactive power control amount ΔVar if necessary, and transmits the Var control parameter VP at predetermined timings appropriate at that time (for example, every few seconds to every few tens of minutes). Note that the timings may be different for some or all of the determination of whether reactive power control is necessary, the calculation of the total amount of reactive power and each reactive power control amount ΔVar if necessary, and the transmission of the Var control parameter VP. The fourth ERC4E controls the operation of each building multi-air-conditioner BA based on the received Var control parameter VP. One customer facility typically includes approximately 10 building multi-air-conditioners BA, each of which operates independently. Therefore, the fourth ERC4E, which manages the building multi-air-conditioners BA for each customer, allocates target reactive power based on the requested reactive power control command to each building multi-air-conditioner BA belonging to the customer (step S5). The VarDR server VS may also perform part of the processing of the DERMS server DS or act as an intermediary in that processing. For example, the VarDR server VS may receive the total reactive power for its area and allocate it to multiple customer facilities as reactive power control amounts ΔVar. Each of the fourth ERC4Es for those customer facilities may then allocate the reactive power control amounts ΔVar allocated by the VarDR server VS to each building multi-air-conditioner BA. Each Var control parameter VP is a parameter of a VQ droop curve. The VQ droop curve is plotted on a coordinate system where the horizontal axis represents V (connection point voltage), the positive side of the vertical axis represents the amount of reactive power injected into the interconnection point, and the negative side of the vertical axis represents the amount of reactive power injected into the interconnection point. The VQ droop curve includes a straight line segment of a predetermined length sloping downward to the right on the coordinate system and two horizontal line segments connected to both sides of the straight line segment. The straight line segment intersects with the horizontal axis at a predetermined reference point (e.g., a grid voltage of 6600 V). The slope of the straight line segment is determined by the amount of reactive power injected into the interconnection point GP when the voltage drops by a predetermined amount from the reference point, and the amount of reactive power withdrawn from the interconnection point GP when the voltage drops by a predetermined amount from the reference point. The value of the slope of the straight line segment of the VQ droop curve is the Var control parameter VP. If reactive power is injected into the interconnection point GP and the phase of the current at the interconnection point GP is advanced, the voltage at the interconnection point GP will increase. If reactive power is withdrawn from the interconnection point GP and the phase of the current at the interconnection point GP is delayed, the voltage at the interconnection point GP will decrease. The DERMS server DS determines each VQ droop curve (each Var control parameter VP) based on the status of the interconnection points GP belonging to the area AR. The DERMS server DS may transmit information about the VQ droop curve to the fourth ERC 4E instead of, or together with, the Var control parameter VP. Each Var control parameter VP may be a value other than the slope of the linear portion of the VQ droop curve.

[0030] The allocation of target reactive power to the multiple building multi-air conditioners BA in the customer facility to which the reactive power control amount ΔVar is allocated by the fourth ERC4E (step S5) will be described in further detail. The DERMS reactive power command value (total reactive power in the customer facility) c (number for each customer facility) is Q c ADR The fourth ERC4E is the total reactive power Q c ADR to B building multi-air conditioners BA respectively b^ AC(b=1,2,…,b,…,B) where Q b^ AC The "^" in the above is originally written above the b, but due to expression constraints, it is sometimes written to the right of the b. If the total reactive power Q related to consumer equipment c is c ADR are evenly allocated to B building multi-air-conditioning units BA, for example, if the building multi-air-conditioning unit BA with number b=1 has been in operation for a considerable period of time and is operating at a relatively low power consumption, while the building multi-air-conditioning unit BA with number b=2 has just started operation and is operating at a relatively high power consumption, the building multi-air-conditioning unit BA with number b=1, which has more capacity, will not be utilized to its full potential, and the operation of the building multi-air-conditioning unit BA with number b=2 will likely be hindered, and the current air-conditioning status of each building multi-air-conditioning unit BA will not be taken into account. Also, the rated power consumption P of each building multi-air-conditioning unit BA b R Even if proportional allocation is made, the current air conditioning status of each building multi-air conditioner BA is not taken into account. In the reactive power demand response system 1 of the present invention, the proportional distribution of the target reactive power is determined by the algorithm expressed by the following equation (1): 1 PAC ,…,k b PAC ,…,k B PAC ] is the active power (current value) P of each building multi-air conditioner BA b AC is the proportionality coefficient of [k 1 TSA ,…,k b TSA ,…,k B TSA ] is the room temperature deviation T b SA The proportional coefficient of the room temperature deviation T b SA is the average difference between the current room temperature and the set temperature in each indoor unit AN of the building multi-air conditioner BA. 1* TSA ,…,k b* TSA ,…,kB* TSA As is well known, the set temperature is obtained from the building multi-air conditioner BA (each indoor unit AN), and the current room temperature is obtained from the temperature sensor of each air-conditioning target (each indoor unit AN).

[0031]

number

[0032] The fourth ERC4E is the current power proportional coefficient [k 1 PAC ,…,k b PAC ,…,k B PAC ], the current power of each building multi-air conditioner BA measured using a known method is allocated and distributed as is. On the other hand, the fourth ERC4E is the proportional coefficient of the room temperature deviation [k 1 TSA ,…,k b TSA ,…,k B TSA ] is allocated by focusing on the following property. That is, room temperature deviation is such that small deviations of ±1°C or less are not noticed or tolerated by many ordinary people, but deviations exceeding ±1°C are noticed by ordinary people and reduce the sense of comfort, and the greater the deviation, the more rapidly the comfort level decreases nonlinearly. In consideration of this property, the VarDR server VS allocates [k 1 TSA ,…,k b TSA ,…,k B TSA ] is allocated and distributed, and the proportional distribution coefficient is [k 1* TSA ,…,k b* TSA ,…,k B* TSA ] where the function argmin is the function of the variables (each T b SA The element [k 1 TSA ,…,k b TSA ,…,kB TSA ]. The subscript * indicates optimal allocation.

[0033]

number

[0034] That is, the meaning of equation (2) is that the room temperature deviation T of each building multi-air conditioner BA at the time when the DERMS control command is distributed. b SA The square of the total number of units is minimized by the room temperature deviation proportional coefficient [k 1 TSA ,…,k b TSA ,…,k B TSA ] is allocated and distributed (allocation by the least squares method). In the reactive power demand response system 1, the fourth ERC4E determines the allocation of the target reactive power based on equation (2), thereby minimizing the impact on the air conditioning capacity required by each building multi-air conditioner BA at that time, and ultimately the room temperature deviation that indicates the comfort of each building multi-air conditioner BA, and allowing the fourth ERC4E to achieve the target reactive power based on the requested reactive power control command, thereby contributing to power stability in the distribution system ES. The fourth ERC4E also stores the received Var control parameter VP and references it at specific intervals (for example, at intervals of several tens of seconds to several minutes) to determine the target reactive power allocation each time. When the Var control parameter VP is updated by receiving a new parameter, the fourth ERC4E references the Var control parameter VP. Instead of the least squares method, the allocated room temperature deviation proportional coefficient [k 1* TSA ,…,k b* TSA ,…,k B* TSA] may be determined. The mathematical programming may be linear programming or nonlinear programming. Furthermore, instead of using the proportional coefficient of the room temperature deviation for apportioning the reactive power, the apportioned reactive power corresponding to the value obtained by multiplying the reactive power to be apportioned by the proportional coefficient of the room temperature deviation may be directly determined.

[0035] Figure 4 is a graph showing the control principle of reactive power Q by the active converter AC of the building multi-air conditioner BA. The horizontal axis of the graph in Figure 4 represents the active power P component of the apparent power, and the vertical axis represents the reactive power Q component. The reactive power Q is controlled by manipulating the active power P and power factor cosθ (θ in radians) to the outdoor unit's built-in inverter IN using the active converter AC. An increase in reactive power corresponds to a leading power factor, and a decrease in reactive power corresponds to a lagging power factor. In addition, the control of reactive power Q is performed at the minimum operating power factor cosθ of the active converter AC and the outdoor unit built-in inverter IN. max The limit is based on the rated capacity S of the active converter AC and the inverter IN built into the outdoor unit. max The circle CL in the graph in Figure 4 is centered at the origin and is limited by the rated capacity S max The radius of the circle is , and the power consumed by the active converter AC and the outdoor unit built-in inverter IN during operation is contained within this circle CL.

[0036] The target reactive power commanded by the DERMS server DS to the 4th ERC4E of the building multi-air conditioner BA is controlled by the Var control parameter VP. TGT Then, the fourth ERC4E will set the target reactive power Q according to its own operating mode. TGT This switches the operation so that the target reactive power Q is generated while suppressing the deterioration of the air conditioning comfort of the building multi-air conditioner BA. TGT and provide it to the distribution grid ES through its own interconnection point GP. The active powers P0 to P3 located at the boundaries of the respective operation modes are expressed by the following equations (3) to (6).

[0037]

number

[0038] When the fourth ERC4E is in the first operation mode M1 in which the range of the active power P is P0 < P ≤ P1 due to the operation of the building multi-air conditioner BA, the minimum operating power factor cosθ max consumes active power P proportional to the reactive power Q in order to maintain the target reactive power Q TGT while maintaining it. The range of the reactive power Q in the first operation mode M1 is Q ≤ Ptanθ max becomes. Target reactive power Q TGT In a normal building multi-air conditioner BA that does not correspond to the target reactive power Q, when the room temperature reaches near the set temperature, the operation of the outdoor unit OU stops, and the supply of refrigerant to each indoor unit AN stops (so-called thermo-off). Therefore, if we try to maintain the minimum operating power factor cosθ max the reactive power Q cannot be supplied either. Therefore, when the fourth ERC4E corresponds to the target reactive power Q TGT it consumes active power P in order to supply the reactive power Q, so even if the room temperature reaches near the set temperature. However, when the room temperature deviation becomes a predetermined value (for example, ±2°C) or more, in order to suppress the influence of the decrease in comfort, the correspondence to the target reactive power Q TGT is stopped (opt-out). That is, the fourth ERC4E allows a room temperature deviation within a predetermined value and consumes active power P in order to supply the reactive power Q.

[0039] When the fourth ERC4E is in the second operation mode M2 in which the range of the active power P is P1 < P ≤ P2, it can operate at a minimum operating power factor cosθ max or more for any active power P, and since it can supply the target reactive power Q TGT it is not subject to the limitation of the active power P, and the room temperature can be controlled as usual. The range of the reactive power Q in the second operation mode M2 is Q ≤ Q TGT becomes.

[0040] When the fourth ERC4E is in the third operation mode M3 where the range of the active power P is P2 < P ≤ P3, the rated capacity S of the active converter AC and the inverter IN built in the outdoor unit max (= P3) limits the supply of the reactive power Q, resulting in a decrease in the supply of the reactive power Q. Therefore, the fourth ERC4E reduces the active power P to below the active power P2 that can supply the target reactive power Q TGT . The range of the reactive power Q in the third operation mode M3 is Q ≤ (S max 2 - P 2 ) 1 / 2 .

[0041] In this way, the active converter AC controlled by the fourth ERC4E controls the active power P for the air conditioning of the building multi - air conditioner BA to which it belongs, thereby generating the reactive power Q related to the target reactive power Q allocated to the building multi - air conditioner BA. TGT

[0042] [Simulation example of the reactive power demand response system 1, etc.] Regarding the reactive power demand response system 1 and the comparative example, a simulation was performed using a computer with a model of the building multi - air conditioner BA. [[ID=2"]] In the reactive power demand response system 1, the fourth ERC4E apportions the total reactive power Q to a plurality of building multi - air conditioners BA belonging to one customer facility c according to the above formulas (1) and (2), and generates a reactive power output command Q c ADR for the building multi - air conditioner BA numbered b. b^ AC The coefficient k c ADR that apportions the total reactive power Q corresponding to the reactive power control component ΔVar required for the customer facility c to each building multi - air conditioner BA b PAC , k b* TSAHere, α1 is the sensitivity coefficient of power consumption (set to 1.0 here), α2 is the sensitivity coefficient of average room temperature deviation (set to 2.0 here), and P b is the active power (kW) consumed for air conditioning by the building multi-air conditioner BA numbered b, and P b max is the rated power consumption (kW) of the building multi-air conditioner BA numbered b, and T b SA is the room temperature setting deviation (°C) weighted by the capacity of multiple indoor units AN connected to the building multi-air-conditioner BA numbered b. The information required for calculating the formulas (1), (2), (7), and (8) is sent to the VarDR server VS and the DERMS server DS, which store this information. Furthermore, in the reactive power demand response system 1, the total reactive power Q c ADR As an example, the allocation is to be done every 5 minutes.

[0043]

number

[0044] In the comparative example, the total reactive power Q required by the customer equipment c c ADR For the building multi-air-conditioner BA numbered b, simply divide by the number B of building multi-air-conditioners BA belonging to consumer equipment c as shown in the following equation (9), and the reactive power output command Q for each building multi-air-conditioner BA is calculated. b^ AC It was decided that the number of participants would be allocated equally.

[0045]

number

[0046] The model of the building multi-air conditioner BA is mainly formed by a recurrence equation between the instantaneous power consumption of the building multi-air conditioner BA and the building's indoor air temperature. The computer that runs the simulation performs a recurrence calculation of the power recurrence equation expressed by the following equations (10) to (12) and the room temperature recurrence equation expressed by the following equations (13) to (15) every predetermined time (here, every second). The power recurrence formula is related to the DEAMS simulator (distribution system ES). The DEAMS simulator implements a model of the control principle of reactive power Q by the active converter AC of the building multi-air conditioner BA, as shown in Figure 4, etc., and a comparative example model of the control principle of reactive power Q (equal distribution).

[0047]

number

[0048] Table 1 below shows various execution parameters in the simulation. Here, in both the reactive power demand response system 1 and the comparative example, it is assumed that two building multi-air conditioners BA (numbered b=1, 2) belong to a certain consumer facility c. There is the following difference in the air conditioning status of these two building multi-air conditioners BA. That is, the internal heat generation load of the building multi-air conditioner BA numbered b=2 is 1.8 times the internal heat generation load of the building multi-air conditioner BA numbered b=1. It is assumed that the internal heat generation load does not fluctuate in the simulation. In addition, the DERMS server DS transmits the total reactive power Q c ADR = 20 (var) is required to be supplied to the power distribution system ES, and the reactive power demand response system 1 and the comparative example each supply a total reactive power Q c ADR By allocating the total reactive power Q c ADRThis simulation is performed up to t=30 min.

[0049] [Table 1]

[0050] FIG. 5(A) shows the effective power P b AC , reactive power Q b AC and room temperature deviation T b SA 5B is a graph showing the change over time of the active power P b AC , reactive power Q b AC and room temperature deviation T b SA 10 is a graph showing the change over time. Reactive power Q b AC Before the start of the control (t<10), in both the reactive power demand response system 1 and the comparative example, each building multi-air conditioner BA with numbers b=1 and 2 is in a steady state where the heat balance between the heat load and the cooling capacity is maintained at the set temperature, and the room temperature deviation T b SA is maintained at 0°C. However, the effective power required to achieve heat balance differs depending on the heat load of the building multi-air conditioner BA, with the building multi-air conditioner BA with number b=1, which has a low heat load, consuming approximately 10kW, while the building multi-air conditioner BA with number b=2, which has a high heat load, consumes approximately 14kW. Reactive power Q b AC After the start of control (t≦10), in the comparative example, the total reactive power Q c ADR = 20 is distributed evenly, and each building multi-air conditioner BA with number b = 1, 2 has reactive power Q b AC The company will supply the following: Here, in the building multi-air conditioner BA with low heat load number b=1, the effective power P 1 ACWhile the reactive power Q is maintained at 10kW 1 AC Even if the inverter is supplied at 10 kvar, the apparent power is 14.1 kVA, and the rated capacity S of the active converter AC and the inverter IN built into the outdoor unit max Active power P = 15kVA not to exceed 1 AC If the temperature deviation T is maintained, the cooling capacity will also be maintained. 1 SA is kept at 0°C. On the other hand, in the building multi-air conditioner BA with a high heat load number b=2, the effective power P 2 AC While the reactive power Q remains at 14kW 2 AC Even if you try to supply 10kvar, the apparent power will be 17.2kVA, and the rated capacity S of the active converter AC and the outdoor unit built-in inverter IN max = 15kVA, so if this continues, the reactive power Q 2 AC Therefore, the fourth ERC4E of the building multi-air conditioner BA with number b=2 can supply the effective power P 2 AC Then, the cooling capacity of the building multi-air conditioner BA with number b=2 decreases, the heat balance with the heat load is lost, and the room temperature starts to rise. At t=30 min, which is the end of the simulation, the room temperature deviation T 1 SA Although the temperature is 0℃, the room temperature deviation T 2 SA exceeds +1°C, which is the standard for maintaining comfort.

[0051] In contrast, in reactive power demand response system 1, reactive power Q b AC After the control starts (t≦10), the total reactive power Q c ADR Re-allocate. In the first allocation at t=10 min, the room temperature deviation T b SA are both at 0°C and there is no difference, whereas the active power Pb AC Since the building multi-air conditioner BA with number b=2 consumes more power than the building multi-air conditioner BA with number b=1, the reactive power is Q 1 AC >Q 2 AC In the building multi-air conditioner BA with number b=2, the reactive power Q 2 AC For the supply of active power P 2 AC is reduced, so the room temperature deviation T 2 SA increases. In the second distribution at t=15min, the room temperature deviation T 2 SA is rising, the active power P 2 AC Since k is also decreasing, b PAC +k b* TSA The total value of the reactive power Q b AC There will be no change in the distribution of In the third distribution at t=20 min, the room temperature deviation T 2 SA rises to 0.5℃, while the room temperature deviation T 1 SA Since the temperature remains around 0°C and there is room for indoor comfort, the reactive power Q of the building multi-air conditioner BA with number b=1 1 AC While increasing, the reactive power Q of the building multi-air conditioner BA with number b=2 2 AC Here, even in the building multi-air conditioner BA with number b=1, the active power P 1 AC is reduced, the thermal balance between the cooling capacity and the heat load is disrupted, and the room temperature deviation T 1 SA In addition, in the building multi-air conditioner BA with number b=2, the reactive power Q2 AC The decrease in the temperature deviation T 1 SA The increase in will be moderate. The fourth allocation at t=25 min follows the same trend as the third allocation at t=20 min. In this way, in the reactive power demand response system 1, the total reactive power Q c ADR Each reactive power Q b AC Therefore, the reactive power demand response system 1 allocates the total reactive power Q c ADR While contributing to the stabilization of the power distribution system ES in response to b SA The temperature is kept from exceeding +1°C in any of the building multi-air conditioners BA, thereby preventing a decrease in the comfort of the air conditioning provided by each building multi-air conditioner BA.

[0052] [Effects of the invention for transformer overload protection in substations] The reactive power demand response system 1 described above transmits the total reactive power Q requested for the customer equipment to the power distribution system ES. c ADR The building multi-air conditioner BA includes a computer (fourth ERC 4E) that controls each of the building multi-air conditioners BA so that reactive power (reactive power) is supplied by the building multi-air conditioners BA. Therefore, a reactive power demand response system 1 is provided that can control the voltage of the interconnection point GP by controlling the input / output and amount of reactive power Q to / from the interconnection point GP associated with multiple building multi-air conditioners BA in the distribution system ES. Because building multi-air conditioners BA are originally widely present in the distribution system ES, the reactive power demand response system 1 can handle multiple building multi-air conditioners BA adjacent to a point in the distribution system ES that requires voltage control. Furthermore, compared to other DER devices (photovoltaic power generation system D1, storage battery system D2, rapid charger D3), building multi-air conditioners BA can provide reactive power Q for a longer period of time without significantly impairing their original functions, and the reactive power demand response system 1 controls the voltage of the interconnection point GP at a more appropriate timing (to be able to respond more quickly to voltage fluctuations in the distribution system ES).

[0053] Also, the 4th ERC4E is the total reactive power Q c ADR For each building multi-air conditioner BA, the room temperature deviation T b SA The target reactive power Q for each building multi-air conditioner BA is calculated based on the mathematical programming method for TGT Therefore, the reactive power demand response system 1 can supply reactive power Q to the power distribution system ES while taking into consideration the comfort of the air conditioning in each building multi-air conditioner BA. Furthermore, the mathematical programming is b SA The total reactive power Q required for the customer equipment is calculated so that the sum of the squares of c ADR The proportional distribution coefficient for each building multi-air conditioner BA [k 1* TSA ,…,k b* TSA ,…,k B* TSA ] is determined by the least squares method. Therefore, the reactive power demand response system 1 can supply reactive power Q to the power distribution system ES while more easily considering the comfort of the air conditioning in each building multi-air conditioner BA.

[0054] In addition, each building multi-air conditioner BA has a compressor motor CM, an outdoor unit built-in inverter IN connected to the compressor motor CM, and an active converter AC that adjusts the power to the outdoor unit built-in inverter IN. Therefore, in the reactive power demand response system 1, each building multi-air conditioner BA more efficiently supplies reactive power Q to the power distribution system ES. In addition, each active converter AC controls the active power P for the air conditioning of the building multi-air conditioner BA to which it belongs, thereby achieving the target reactive power Q allocated to the building multi-air conditioner BA. TGT Therefore, in the reactive power demand response system 1, in each building multi-air conditioner BA, the reactive power Q is supplied to the power distribution system ES more efficiently.

[0055] [Examples of changes] At least one of the embodiments and simulations of the present invention is not limited to the above-described embodiments and modifications, and may include further modifications as follows. At least one of the number of various computers and their arrangement on the network, the configuration of the power system, various formulas, and circuits and commands related to control may be changed to other logically equivalent ones. [Explanation of symbols]

[0056] 1··Reactive power demand response system, 4E··4th ERC (computer), AC··Active converter, BA··Building multi-air conditioner, CM··Compressor motor, DS··DERMS server, ES··Power distribution system, IN··Outdoor unit built-in inverter (inverter), P··Active power, Q··Reactive power, Q c ADR Total reactive power, Q TGT Target reactive power, T b SA ··Room temperature deviation, VS··VarDR server.

Claims

1. a computer that controls each of the plurality of building multi-air-conditioners so that reactive power is supplied to the power distribution system by the building multi-air-conditioners; The computer allocates the reactive power to each of the building multi-air conditioners based on a mathematical programming method related to room temperature deviation, and allocates target reactive power to each of the building multi-air conditioners. A reactive power demand response system comprising:

2. The mathematical programming is a least squares method that determines an apportionment proportional coefficient for the reactive power for each building multi-air conditioner so that the sum of the squares of the room temperature deviations is minimized, or determines an apportioned reactive power for each building multi-air conditioner that corresponds to the reactive power multiplied by the apportionment proportional coefficient.

2. The reactive power demand response system according to claim 1 .

3. The building multi-air conditioner has a compressor motor, an inverter connected to the compressor motor, and an active converter that adjusts power to the inverter.

3. The reactive power demand response system according to claim 1 or 2.

4. The active converter controls the active power for air conditioning of the building multi-air conditioner to which it belongs, thereby generating reactive power related to the target reactive power allocated to the building multi-air conditioner.

4. The reactive power demand response system according to claim 3.

Images