JP5618294B2 - High and low voltage distribution system voltage regulation system - Google Patents
High and low voltage distribution system voltage regulation systemInfo
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- JP5618294B2 JP5618294B2 JP2010230400A JP2010230400A JP5618294B2 JP 5618294 B2 JP5618294 B2 JP 5618294B2 JP 2010230400 A JP2010230400 A JP 2010230400A JP 2010230400 A JP2010230400 A JP 2010230400A JP 5618294 B2 JP5618294 B2 JP 5618294B2
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/30—Reactive power compensation
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/70—Smart grids as climate change mitigation technology in the energy generation sector
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S10/00—Systems supporting electrical power generation, transmission or distribution
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S10/00—Systems supporting electrical power generation, transmission or distribution
- Y04S10/22—Flexible AC transmission systems [FACTS] or power factor or reactive power compensating or correcting units
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- Supply And Distribution Of Alternating Current (AREA)
- Remote Monitoring And Control Of Power-Distribution Networks (AREA)
Description
本発明は、自家発電設備を配電系統に連系した高圧・低圧配電系統電圧調節システムに関する。 The present invention relates to a high-voltage / low-voltage distribution system voltage regulation system in which a private power generation facility is connected to a distribution system.
従来から太陽光発電システム、風力発電、燃料電池、マイクロガスタービン、エンジン発電などの自家発電設備を配電系統に連系して、配電系統との間で電力を送電する分散型電源の導入が、住宅地域を中心に進んでいる。
一方で、このような分散型電源が配電系統に大量に連系されると、分散型電源から生じる逆潮流により配電系統の電圧が上昇し、低圧需要家の受電電圧が、電気事業法で規定された電圧を逸脱するおそれが生じる。
Conventionally, the introduction of distributed power sources that transmit power to and from the distribution system by connecting in-house power generation facilities such as solar power generation systems, wind power generation, fuel cells, micro gas turbines, and engine power generation to the distribution system, Progressing mainly in residential areas.
On the other hand, when such a distributed power source is connected to the power distribution system in large quantities, the reverse power flow from the distributed power source raises the voltage of the power distribution system, and the voltage received by low-voltage consumers is regulated by the Electricity Business Law. There is a risk of deviating from the applied voltage.
このため、以下、自家発電設備として太陽光発電システムを例に取ると、下記特許文献１、２にみられるように、パワーコンディショナなどには、低圧需要家の受電電圧の上昇を抑制することを目的とした電圧上昇抑制機能が備えられる。 For this reason, when taking a solar power generation system as an example of private power generation equipment, as shown in Patent Documents 1 and 2, the power conditioner and the like suppress an increase in received voltage of low-voltage consumers. A voltage rise suppressing function for the purpose is provided.
すなわち、一般住宅用太陽光発電システムでは、太陽電池パネル群が太陽光を受光して直流電力を発生させ、それをパワーコンディショナで通常２００Ｖの交流電力に変換し、電力系統側へ電力を送り出す。これにより生じる、需要家側から電力系統側への電力の流れを、逆潮流という。分散型電源が配電系統に大量に導入されると、分散型電源からの逆潮流により配電系統の電圧が上昇し、低圧需要家の受電電圧が、電気事業法で規定された電圧（１００ボルト系では１０１±６Ｖ、２００ボルト系では２０２±２０Ｖ）を逸脱するおそれが生じる。 In other words, in a general residential solar power generation system, a solar panel group receives sunlight to generate DC power, which is converted into AC power of 200 V normally by a power conditioner, and is sent to the power system side. . The flow of electric power from the customer side to the power system side caused by this is called reverse power flow. When a large amount of distributed power sources are introduced into the distribution system, the voltage of the distribution system rises due to the reverse power flow from the distributed power source, and the received voltage of the low voltage consumer is the voltage specified by the Electricity Business Law (100 volt system Then, there is a risk of deviating from 101 ± 6 V and 202 ± 20 V in a 200 volt system.
このため、日本国内で太陽光発電システムを配電系統に連系するにあたっては、下記非特許文献１に示されるように、太陽光発電システムのパワーコンディショナなどには、低圧需要家の受電電圧の上昇を抑制することを目的とした電圧上昇抑制機能を備えることが義務づけられている。
具体的には、配電系統と太陽光発電システムとの連系点における電圧が適正値を逸脱するおそれがある時は、太陽光発電システムにおいて電圧を調整する対策を行うべきであること、そして、逆潮流がある場合の運転力率の下限値を０．８５とすることが示されている。なお、運転力率とは、分母が有効電力の２乗と進相無効電力の２乗との和の平方根で、分子が有効電力の計算式で計算される値である。
For this reason, when connecting a photovoltaic power generation system to a power distribution system in Japan, as shown in Non-Patent Document 1 below, the power conditioner of the photovoltaic power generation system has a received voltage of a low voltage consumer. It is obliged to provide a voltage rise suppression function for the purpose of suppressing the increase.
Specifically, when the voltage at the connection point between the power distribution system and the photovoltaic power generation system may deviate from the appropriate value, measures to adjust the voltage in the photovoltaic power generation system should be taken, and It is shown that the lower limit value of the driving power factor when there is a reverse power flow is 0.85. The driving power factor is a value obtained by calculating the active power using the square root of the sum of the square of the active power and the square of the fast reactive power.
このパワーコンディショナは、太陽電池からの発電を直流から交流に変換するインバータや保護装置などの制御装置などから構成され、配電系統と太陽光発電システムとの連系点で測定された電圧に基づき、電圧上昇を抑制するように電力を制御する。
電圧上昇抑制するための手法として、進相無効電力（電流の位相が電圧の位相より９０度進んでおり、商用交流１サイクルあたりで正味のエネルギー伝送には寄与しない電力）を発生させるように電力を制御することが挙げられ、連系点での電圧が上限値を上回るとき、進相無効電力を増加させることにより、接続点の電圧上昇を抑制することができる。しかし、電圧上昇を抑制するため進相無効電力を増加させすぎると、運転力率が下限値０．８５を下回ってしまうことから、進相無効電力の増加による電圧上昇抑制には限度がある。このため、このような場合には、有効電力（発電電力）を低減させる「出力抑制制御」を行わざるを得ない。
This power conditioner is composed of control devices such as inverters and protection devices that convert the power generation from solar cells from direct current to alternating current, and is based on the voltage measured at the interconnection point between the distribution system and the photovoltaic power generation system. The power is controlled so as to suppress the voltage rise.
As a method for suppressing the voltage rise, power is generated so as to generate fast reactive power (power whose current phase is 90 degrees ahead of voltage phase and does not contribute to net energy transmission per commercial AC cycle). When the voltage at the interconnection point exceeds the upper limit value, it is possible to suppress the voltage increase at the connection point by increasing the phase advance reactive power. However, if the phase advance reactive power is increased too much in order to suppress the voltage rise, the driving power factor falls below the lower limit value 0.85, and thus there is a limit to the voltage rise suppression due to the increase of the phase advance reactive power. For this reason, in such a case, “output suppression control” for reducing active power (generated power) must be performed.
太陽光発電システムは通常、電圧上昇の問題がなければ、太陽電池パネル群に入射する太陽光エネルギーに応じて最大の電気エネルギーを取り出すように運転（最大出力点追従運転）し、それに応じた有効電力を出力する。有効電力を低減させる場合は、より多くの有効電力を出力できる太陽光の入射があるのに、それを無駄にすることになるので、有効電力を過度に低減させないように制御することが望ましい。最大出力点追従運転を行う場合の有効電力出力と出力抑制制御時の有効電力出力との差を、出力抑制損失という。一般住宅用太陽光発電システムが配電系統に大量連系すると逆潮流が増えて電圧が上昇しやすくなるため、出力抑制制御が頻繁に行われ、システム運転効率が低下する。 If there is no problem of voltage rise, the solar power generation system is usually operated so as to extract the maximum electric energy according to the solar energy incident on the solar panel group (maximum output point tracking operation), and effective according to it. Output power. When reducing the active power, there is incident sunlight that can output more active power, but it is wasted. Therefore, it is desirable to control so that the active power is not excessively reduced. The difference between the active power output when performing the maximum output point following operation and the active power output during the output suppression control is referred to as output suppression loss. When a general residential solar power generation system is connected to the power distribution system in large quantities, reverse power flow increases and the voltage tends to rise. Therefore, output suppression control is frequently performed, and system operation efficiency decreases.
以上のことから、複数台の太陽光発電システムが配電系統に連系されているシステムにおいて、パワーコンディショナにより有効電力を過度に低減させずに、連系点の電圧の上昇を確実に抑制することが重要な課題となる。
そこで、下記非特許文献２、３に見られるように、高圧自動電圧調整器（ＳＶＲ）、静止型無効電力補償装置（ＳＶＣ）及びループバランスコントローラ（ＬＢＣ）の新設による高圧配電系統の電圧調整や、蓄電池を用いた出力抑制回避が検討された。
From the above, in a system in which multiple photovoltaic power generation systems are connected to the distribution system, the power conditioner can reliably suppress the increase in voltage at the connection point without excessively reducing the active power. Is an important issue.
Therefore, as seen in Non-Patent Documents 2 and 3 below, voltage adjustment of the high-voltage distribution system by newly installing a high-voltage automatic voltage regulator (SVR), a static reactive power compensator (SVC), and a loop balance controller (LBC) The avoidance of output suppression using a storage battery was studied.
しかし、上記非特許文献２によるものでは、高額な機器・保守費用が見込まれるほか、費用負担のあり方に関する制度整備が必要である。また上記非特許文献３によるものも、蓄電池の費用や設置スペース、及び充放電損失の発生といった問題を抱えている。
そこで、本発明の目的は、上記の問題点に鑑み、電力潮流を直接扱うＳＶＲ、ＳＶＣ、ＬＢＣといったハードウェアの追加・新設には極力頼らず、パワーコンディショナ（自励式インバータ）や同期発電機により系統連系する分散型電源の無効電力調整機能を有効活用して配電系統全体の電圧を適切に調節するための制御アルゴリズムを確立した高圧・低圧配電系統電圧調節システムを提供することにある。
However, according to Non-Patent Document 2 described above, expensive equipment / maintenance costs are expected, and a system for the cost burden is required. Moreover, the thing by the said nonpatent literature 3 also has problems, such as the expense of a storage battery, installation space, and generation | occurrence | production of charging / discharging loss.
Therefore, in view of the above-described problems, the object of the present invention is not to rely on the addition / new installation of hardware such as SVR, SVC, and LBC that directly handle power flow, and power conditioners (self-excited inverters) and synchronous generators. An object of the present invention is to provide a high-voltage / low-voltage distribution system voltage adjustment system that establishes a control algorithm for appropriately adjusting the voltage of the entire distribution system by effectively utilizing the reactive power adjustment function of the distributed power source connected to the grid.
上記の目的を達成するため、本発明の高圧・低圧配電系統電圧調節システムにおいては、次のような技術的手段を講じた。すなわち、
（１）低圧配電系統に分散型電源が複数連系された特定地域の配電系統において、当該特定地域の高圧配電系統を監視制御する高圧配電系統監視制御装置と、当該特定地域内に設置され、前記高圧配電系統からの高電圧を低電圧に変圧する複数台の変圧器と、該変圧器の２次側に接続された低圧配電系統を監視制御する低圧配電系統監視制御装置と、前記分散型電源毎に配備され、無効電力を制御することにより該分散型電源の連系点電圧を制御するパワーコンディショナとからなり、前記高圧配電系統監視制御装置及び前記低圧配電系統監視制御装置並びに前記パワーコンディショナは、それぞれ双方向通信手段により接続されており、前記パワーコンディショナは、それぞれの連系点電圧を前記低圧配電系統監視制御装置に伝達し、かつ前記低圧配電系統監視制御装置は、各パワーコンディショナの連系点電圧が規定の上限値以下、かつ、その運転力率が規定の下限値以上を維持できるよう、該連系点電圧に基づいて、当該低圧配電系統に属する前記変圧器毎に一次電圧調整要求量ΔＶｒｉ（ｉ＝１、・・・、Ｎ）を演算して前記高圧配電系統監視制御装置に送信するとともに、前記高圧配電系統監視制御装置は、該一次電圧調整要求量に基づいて前記低圧配電系統監視制御装置のそれぞれに当該低圧配電系統における無効電力調整指令値ΔＱｒｊ（ｊ＝１、・・・、Ｎ）を送信し、前記低圧配電系統監視装置のそれぞれは、当該低圧配電系統に割り当てられた無効電力調整指令値ΔＱｒｊに基づいて当該低圧配電系統につながる各パワーコンディショナに無効電力調整要求量を割り振るようにした。
In order to achieve the above object, the following technical means were taken in the high-voltage / low-voltage distribution system voltage regulation system of the present invention. That is,
(1) In a specific area distribution system in which a plurality of distributed power sources are connected to a low-voltage distribution system, a high-voltage distribution system monitoring and control device that monitors and controls the high-voltage distribution system in the specific area, and installed in the specific area, A plurality of transformers for transforming a high voltage from the high-voltage distribution system to a low voltage, a low-voltage distribution system monitoring and control device for monitoring and controlling a low-voltage distribution system connected to a secondary side of the transformer, and the distributed type A power conditioner that is provided for each power source and controls the interconnection point voltage of the distributed power source by controlling reactive power, the high-voltage distribution system monitoring control device, the low-voltage distribution system monitoring control device, and the power The conditioners are respectively connected by bidirectional communication means, and the power conditioners transmit the respective interconnection point voltages to the low-voltage distribution system monitoring and control device, and The low-voltage distribution system monitoring and control device is based on the interconnection point voltage so that the interconnection point voltage of each power conditioner can be maintained below the prescribed upper limit value and the operating power factor can be maintained above the prescribed lower limit value. The primary voltage adjustment request amount ΔVri (i = 1,..., N) is calculated for each of the transformers belonging to the low-voltage distribution system and transmitted to the high-voltage distribution system monitoring and control device, and the high-voltage distribution system monitoring is performed. The control device transmits a reactive power adjustment command value ΔQrj (j = 1,..., N) in the low-voltage distribution system to each of the low-voltage distribution system monitoring and control devices based on the primary voltage adjustment request amount, each of the low-voltage distribution system monitoring device, the reactive power adjustment request amount to each of the power conditioner connected to the low-voltage distribution systems on the basis of the low-voltage distribution system to the assigned reactive power adjustment command value ΔQrj Ri was like to shake.
（２）上記の高圧・低圧配電系統電圧調節システムにおいて、前記低圧配電系統監視制御装置及び前記パワーコンディショナとの双方向通信手段に、電力線搬送通信（ＰＬＣ： Ｐｏｗｅｒ Ｌｉｎｅ Ｃｏｍｍｕｎｉｃａｔｉｏｎ）を採用した。 (2) In the high voltage / low voltage distribution system voltage regulation system described above, power line communication (PLC) is adopted as a bidirectional communication means with the low voltage distribution system monitoring and control device and the power conditioner.
（３）上記の高圧・低圧配電系統電圧調節システムにおいて、前記高圧配電系統監視制御
装置が前記低圧配電系統のそれぞれの前記無効電力調整指令値ΔＱｒｊを算出する際に、前記一次電圧調整要求量ΔＶｒｉとΔＱｒｊに関する連立方程式を用い、前記一次電圧調整要求量ΔＶｒｉの誤差の二乗和が最小になるように、各低圧配電系統におけるΔＱｒｊを算出するようにした。
(3) In the high-voltage / low-voltage distribution system voltage regulation system, when the high-voltage distribution system monitoring and control device calculates the reactive power adjustment command value ΔQrj of each of the low-voltage distribution systems, the primary voltage adjustment request amount ΔVri And ΔQrj are used to calculate ΔQrj in each low-voltage distribution system so that the sum of squares of errors in the primary voltage adjustment request amount ΔVri is minimized.
（４）上記の高圧・低圧配電系統電圧調節システムにおいて、前記高圧配電系統監視制御装置が前記低圧配電系統のそれぞれの前記無効電力調整指令値ΔＱｒｊを算出する際に、前記一次電圧調整要求量ΔＶｒｉとΔＱｒｊに関する連立方程式を用い、前記一次電圧調整要求量ΔＶｒｉの誤差の二乗和に加えて、特定のパワーコンディショナからの無効電力が他のパワーコンディショナからの無効電力の平均値から大きくずれないようにする項を加えて、各低圧配電系統におけるΔＱｒｊを算出するようにした。 (4) In the high-voltage / low-voltage distribution system voltage regulation system, when the high-voltage distribution system monitoring and control device calculates the reactive power adjustment command value ΔQrj of each of the low-voltage distribution systems, the primary voltage adjustment request amount ΔVri In addition to the square sum of errors of the primary voltage adjustment required amount ΔVri, the reactive power from a specific power conditioner does not deviate significantly from the average value of reactive power from other power conditioners. In addition, the term “Qrj” in each low-voltage distribution system is calculated.
（５）上記の高圧・低圧配電系統電圧調節システムにおいて、一次巻線と二次巻線の巻数比がＧである柱上変圧器の２次側の低圧配電系統につながるパワーコンディショナのうち、発電可能電力を出力すると連系点電圧が前記規定の上限値を超えているものの台数がｓ台であり、その逸脱幅がそれぞれΔｖｐｖｋ（ｋ＝１、・・・、ｓ）であったとき、当該低圧配電系統の低圧配電系統監視制御装置が伝達する一次電圧調整要求量ΔＶｒｉを−Δｖｐｖｋの総和のＧ倍とした。 (5) Among the power conditioners connected to the low-voltage distribution system on the secondary side of the pole transformer in which the turn ratio of the primary winding and the secondary winding is G in the high-voltage / low-voltage distribution system voltage regulation system, When the power that can be generated is output and the interconnection point voltage exceeds the specified upper limit, the number is s, and the deviation width is Δv pvk (k = 1,..., S), respectively. The primary voltage adjustment request amount ΔV ri transmitted by the low-voltage distribution system monitoring and control device of the low-voltage distribution system is set to G times the total sum of −Δv pvk .
（６）上記の高圧・低圧配電系統電圧調節システムにおいて、各低圧配電系統監視装置は当該低圧配電系統につながるパワーコンディショナに無効電力調整要求量を割り振る際、パワーコンディショナそれぞれに運転力率を指令値として送信し、各パワーコンディショナは自身の運転力率が上記指令値以下となるように無効電力を出力するようにした。 (6) In the voltage regulation system for the high voltage / low voltage distribution system, each low voltage distribution system monitoring device assigns the operating power factor to each power conditioner when allocating the reactive power adjustment request amount to the power conditioner connected to the low voltage distribution system. It was transmitted as a command value, and each power conditioner was designed to output reactive power so that its driving power factor was not more than the command value.
本発明によれば、無効電力を制御することにより分散型電源の連系点電圧を制御するパワーコンディショナが、それぞれの連系点電圧を低圧配電系統監視制御装置に伝達し、また、低圧配電系統監視制御装置が、各パワーコンディショナの連系点電圧が規定の上限値以下、かつ、その運転力率が規定の下限値以上を維持できるよう、該連系点電圧に基づいて、当該低圧配電系統に属する前記変圧器毎に一次電圧調整要求量ΔＶｒｉ（ｉ＝１、・・・、Ｎ）を演算する。この一次電圧調整要求量に基づいて、高圧配電系統監視制御装置が、低圧配電系統監視制御装置のそれぞれに無効電力調整指令値ΔＱｒｊ（ｊ＝１、・・・、Ｎ）を送信して、割り当てられた無効電力調整指令値ΔＱｒｊに基づいて各パワーコンディショナに無効電力調整要求量を適切に割り振ることができる。
したがって、電力潮流を直接扱うＳＶＲ、ＳＶＣ、ＬＢＣといったハードウェアを追加・新設することなく、パワーコンディショナや同期発電機により系統連系する分散型電源の無効電力調整機能を最大限に有効活用して、配電系統全体の電圧を適切に制御し、システムの運転効率を向上することが可能になる。
According to the present invention, the power conditioner that controls the interconnection point voltage of the distributed power source by controlling the reactive power transmits each interconnection point voltage to the low voltage distribution system monitoring and control device, and the low voltage distribution system. The grid monitoring and control device, based on the interconnection point voltage, maintains the low voltage so that the interconnection point voltage of each power conditioner can be maintained below the prescribed upper limit value and the operating power factor is above the prescribed lower limit value. A primary voltage adjustment request amount ΔVri (i = 1,..., N) is calculated for each transformer belonging to the distribution system. Based on this primary voltage adjustment request amount, the high-voltage distribution system monitoring and control device transmits a reactive power adjustment command value ΔQrj (j = 1,..., N) to each of the low-voltage distribution system monitoring and control devices for allocation. The reactive power adjustment request amount can be appropriately allocated to each power conditioner based on the reactive power adjustment command value ΔQrj.
Therefore, the reactive power adjustment function of the distributed power source connected to the grid by power conditioners and synchronous generators can be utilized to the maximum extent without adding or newly installing hardware such as SVR, SVC, and LBC that directly handle power flow. Thus, it is possible to appropriately control the voltage of the entire distribution system and improve the operation efficiency of the system.
そこで、以下図面を参照して、本発明の実施例について説明する。 Accordingly, embodiments of the present invention will be described below with reference to the drawings.
本実施例では、前提として図２に示されるような、高圧配電系統により給電されるエリアを想定する。
この高圧配電系統には、図２のように０から７３までの合計７４箇所の節点に番号（大括弧で囲った数字）をつけた。そのうち柱上変圧器を介して図３の低圧配電系統がつながっている節点（黒塗り逆三角形で表示）は４８箇所ある。
上記の節点には、３台の単相柱上変圧器が各相間に１台ずつ合計３台つながっている。白塗り逆三角形は三相高圧負荷を示し、それぞれ３００ｋＷを力率１で消費しているとする。なお、このエリアは完全に三相平衡であるものとする。
In the present embodiment, an area supplied with power by a high-voltage distribution system as shown in FIG. 2 is assumed as a premise.
In this high-voltage distribution system, numbers (numbers enclosed in square brackets) are given to a total of 74 nodes from 0 to 73 as shown in FIG. Among them, there are 48 nodes (indicated by black inverted triangles) where the low-voltage distribution system of FIG. 3 is connected via pole transformers.
In total, three single-phase pole transformers are connected to each node, one between each phase. White triangles indicate three-phase high-pressure loads, and each consumes 300 kW with a power factor of 1. It is assumed that this area is completely three-phase balanced.
すべての柱上変圧器は巻数比を６６００：２１０に設定しているものとし、無負荷状態では、柱上変圧器の１次電圧６６００Ｖのとき、二次電圧が２１０Ｖとなる。二次巻線には巻線両端の他、中性点タップがあり、合計３つの端子が出ている。低圧配電線はこの３つの端子からそれぞれ１本ずつ、合計３本の線で構成されている。低圧配電系統の２００Ｖ系とは二次巻線の両端からの２本の電力線の間の電圧であり、１００Ｖ系とは中性点タップからの線と、どちらか１本の電力線の間の電圧である。 All pole transformers are assumed to have a turns ratio of 6600: 210. In the no-load state, when the primary voltage of the pole transformer is 6600V, the secondary voltage is 210V. The secondary winding has neutral point taps in addition to both ends of the winding, and a total of three terminals are provided. The low-voltage distribution line is composed of three wires, one from each of these three terminals. The 200V system of the low-voltage distribution system is the voltage between the two power lines from both ends of the secondary winding, and the 100V system is the voltage between the line from the neutral point tap and one of the power lines. It is.
すべての低圧配電系統において、図３のように、５０ｋＶＡの柱上変圧器の下に１５軒の住宅がつながっており、全住宅に太陽光発電システムを設置していると仮定する。太陽光発電システムは低圧配電系統の２００Ｖ系に連系している。また、それらの連系点に番号（大括弧で囲った数字）をつけた。各住宅における負荷は零とし、各住宅の太陽光発電システムが、１．８ｋＷの有効電力を出力できる日射を得ているとする。 In all the low-voltage distribution systems, as shown in FIG. 3, it is assumed that 15 houses are connected under a 50 kVA pole transformer, and a photovoltaic power generation system is installed in all the houses. The photovoltaic power generation system is linked to the 200V system of the low-voltage distribution system. In addition, numbers (numbers enclosed in square brackets) were attached to these interconnection points. Assume that the load in each house is zero, and the solar power generation system in each house has obtained solar radiation that can output 1.8 kW of effective power.
以上により、図２の配電系統全体で、太陽光発電システムは、４８×３×１５＝２，１６０台つながっている。図２及び図３の線路部分の１線あたりのインピーダンスの値を下記の表１とする。
また、５０ｋＶＡの柱上変圧器の内部インピーダンスを、抵抗分１．２％ｐｕ、リアクタンス分２．１％ｐｕとする。配電用変電所変圧器の送出端電圧を６７００Ｖとする。
The internal impedance of the 50 kVA pole transformer is assumed to be a resistance component of 1.2% pu and a reactance component of 2.1% pu. The sending terminal voltage of the distribution substation transformer is 6700V.
我が国においては、一般住宅は単相三線１００Ｖ／２００Ｖで配線されていることが多いが、この場合１００Ｖは２００Ｖ系の中性線と一方の電圧線との間の電圧であるので、電圧変動の制約は１００Ｖ系の上限１０７Ｖ（このとき２００Ｖ系は２１４Ｖ以上となっている）の方が２００Ｖ系の上限２２２Ｖより厳しい条件となる。本解析では、パワーコンディショナは低圧配電系統の２００Ｖ系に連系するが、１００Ｖ系の上限１０７Ｖの２倍である２１４Ｖを規定上限値として運転することを想定する。 In Japan, ordinary houses are often wired with single-phase three-wire 100V / 200V, but in this case 100V is the voltage between the neutral line of one of the 200V series and one of the voltage lines, The restriction is that the upper limit 107V of the 100V system (at this time, the 200V system is 214V or higher) is more severe than the upper limit 222V of the 200V system. In this analysis, the power conditioner is connected to the 200V system of the low-voltage distribution system, but it is assumed that 214V, which is twice the upper limit 107V of the 100V system, is operated as the specified upper limit value.
比較のため、従来の制御法を行う場合について、次のように動作を想定して解析した。
すなわち、各パワーコンディショナは自身の連系点電圧が２１４Ｖ未満のときは力率１で、２１４Ｖを超えそうになると、まず進相運転（遅れ無効電力を消費）して連系点電圧を下げる。しかし、力率が０．８５を下回る運転は行わず、力率０．８５でも連系点電圧が２１４Ｖを超える場合は、力率を０．８５に保ったまま、連系点電圧が２１４Ｖに下がるまで発電出力（有効電力）を絞る。
For comparison, the case of performing the conventional control method was analyzed assuming the operation as follows.
That is, each power conditioner has a power factor of 1 when its own connection point voltage is less than 214V, and when it is about to exceed 214V, the phase advance operation (consumption of delayed reactive power) is first performed to lower the connection point voltage. . However, if the power factor is not less than 0.85 and the interconnection point voltage exceeds 214V even at a power factor of 0.85, the interconnection point voltage is increased to 214V while maintaining the power factor at 0.85. Reduce power generation output (active power) until it drops.
想定したエリアにおいて、すべてのパワーコンディショナが上記の動作を行った場合について数値解析を行った。その結果得られた、高圧配電系統内の各節点の電圧及び消費電力を図４に、低圧配電系統内の各連系点における電圧（分解能０．１Ｖ）と発電電力と力率を図５に示す。
解析した図３の低圧配電系統は左右対称であるから、図５では右半分の、連系点０から７までの分のみを示しており、連系点０が柱上変圧器直下、連系点７が低圧配電系統末端である。また、低圧配電系統は４８（節点）×３（相）＝１４４あるが、このエリアは完全に三相平衡であるため、図５では各節点の中の代表する１相分のみ示している。このため、図５では４８節点分のデータが記されており、同じ低圧配電系統につながるパワーコンディショナのデータが直線で結ばれている。
Numerical analysis was performed for the case where all inverters performed the above operations in the assumed area. The resulting voltage and power consumption at each node in the high-voltage distribution system are shown in FIG. 4, and the voltage (resolution 0.1 V), generated power and power factor at each interconnection point in the low-voltage distribution system are shown in FIG. Show.
Since the analyzed low-voltage distribution system in FIG. 3 is symmetric, FIG. 5 shows only the right half of the connection points 0 to 7, and the connection point 0 is directly below the pole transformer. Point 7 is the end of the low voltage distribution system. Further, the low-voltage distribution system has 48 (nodes) × 3 (phases) = 144, but since this area is completely three-phase balanced, only one representative phase of each node is shown in FIG. For this reason, in FIG. 5, the data for 48 nodes are shown, and the data of the power conditioner connected to the same low-voltage distribution system is connected with a straight line.
図４の電力消費において、発電による逆潮流はマイナス値で表されている。柱上変圧器を介して低圧配電系統がつながる節点から、１．８（ｋＷ）×１５（台）×３（相）＝８１ｋＷの逆潮流が生じていれば、その低圧配電系統内の太陽光発電システムはすべて、日射から得られる最大限の電力を発電できていることを意味する。図４において、柱上変圧器を介して低圧配電系統がつながる節点のうちのいくつかの節点では逆潮流電力が８１ｋＷを下回っている。このことは、これらの節点につながる低圧配電系統内において、連系点電圧が２１４Ｖに達して出力抑制制御を行っているパワーコンディショナがあることを示している。 In the power consumption of FIG. 4, the reverse power flow due to power generation is represented by a negative value. If a reverse power flow of 1.8 (kW) x 15 (units) x 3 (phase) = 81 kW occurs from the node where the low-voltage distribution system is connected via the pole transformer, the sunlight in the low-voltage distribution system This means that all power generation systems are able to generate the maximum amount of power that can be obtained from solar radiation. In FIG. 4, the reverse power flow is less than 81 kW at some of the nodes to which the low-voltage distribution system is connected via the pole transformer. This indicates that there is a power conditioner in which the interconnection point voltage reaches 214 V and the output suppression control is performed in the low voltage distribution system connected to these nodes.
図５より、各低圧配電系統において、柱上変圧器直下の連系点０につながっているパワーコンディショナはすべて、連系点電圧が２１４Ｖ以下であり、１．８ｋＷを出力し、力率１で運転している。また連系点１につながっているパワーコンディショナの中には、連系点電圧が２１４Ｖに達して力率１未満で運転しているものがあるが、すべて１．８ｋＷを出力している。しかし、連系点２以降では、力率０．８５で出力を１．８ｋＷ未満に絞っているパワーコンディショナがある。連系点６以降では、すべてのパワーコンディショナの連系点電圧が２１４Ｖに達しており力率１未満で運転している。同じ低圧配電系統につながるパワーコンディショナを比較すると、低圧配電線の末端につながるパワーコンディショナほど、連系点電圧が上昇しており、力率が低く、出力電力を絞っている。この原因は、低圧配電線の下流（末端近傍）に連系する場合は、パワーコンディショナから柱上変圧器までの線路抵抗が大きいために逆潮流により連系点電圧が上昇しやすいため、及び上流（柱上変圧器近傍）のパワーコンディショナからの逆潮流による電圧上昇がほぼ線形に加わるためである。 From FIG. 5, in each low-voltage distribution system, all the power conditioners connected to the connection point 0 immediately below the pole transformer have an interconnection point voltage of 214 V or less, output 1.8 kW, and a power factor of 1 I am driving in. Some of the power conditioners connected to the connection point 1 are operating at a power factor of less than 1 because the connection point voltage reaches 214 V, but all output 1.8 kW. However, after the connection point 2, there is a power conditioner in which the output is reduced to less than 1.8 kW with a power factor of 0.85. After the connection point 6, the connection point voltages of all the power conditioners have reached 214V, and the operation is performed at a power factor of less than 1. Comparing power conditioners connected to the same low-voltage distribution system, the power conditioner connected to the end of the low-voltage distribution line has a higher interconnection point voltage, lower power factor, and narrows the output power. The reason for this is that when connecting to the downstream (near the end) of the low-voltage distribution line, the line resistance from the power conditioner to the pole transformer is large, so the connection point voltage tends to rise due to reverse power flow, and This is because the voltage rise due to the reverse power flow from the power conditioner upstream (near the pole transformer) is added almost linearly.
このように従来の制御法では、低圧配電系統の末端付近につながる太陽光発電システムの多くが出力抑制制御を実施するにもかかわらず、低圧配電系統の柱上変圧器近傍の太陽光発電システムは力率１で運転し電圧上昇の抑制に寄与しないという、非効率かつ不公平な状況が生じる。 As described above, in the conventional control method, the solar power generation system in the vicinity of the pole transformer in the low-voltage distribution system is used even though most of the solar power generation systems connected to the vicinity of the end of the low-voltage distribution system perform the output suppression control. An inefficient and unfair situation arises in that it operates at a power factor of 1 and does not contribute to the suppression of voltage rise.
これに対し、本発明の協調制御を行った場合について、次のように動作を想定して解析した。
本発明の高圧・低圧配電系統電圧調節システムの構成を図１に示す。
図１は、図２の一部分に、本発明にしたがい、情報通信及び制御のシステムを追加したものである。
高圧配電線１で構成される高圧配電系統により給電されるエリアには、高圧配電系統監視制御装置２が１台設置されている。また、当該特定地域内に設置され、高圧配電系統からの高電圧を低電圧に変圧する複数台の柱上変圧器３の２次側には、低圧配電線４からなる低圧配電系統が接続され、それぞれ低圧配電系統監視制御装置５が１台ずつ設置されている。各パワーコンディショナ６は、自身がつながる低圧配電系統の低圧配電系統監視制御装置５から無効電力調整指令を受けた場合に限り、自身の連系点電圧が上限２１４Ｖ未満でも力率１から０．８５の間で進相無効電力を出力する。
On the other hand, about the case where the cooperative control of this invention was performed, it analyzed supposing operation | movement as follows.
The configuration of the high-voltage / low-voltage distribution system voltage regulation system of the present invention is shown in FIG.
FIG. 1 is obtained by adding an information communication and control system to a part of FIG. 2 according to the present invention.
One high voltage distribution system monitoring and control device 2 is installed in an area to which power is supplied by the high voltage distribution system constituted by the high voltage distribution line 1. In addition, a low-voltage distribution system comprising low-voltage distribution lines 4 is connected to the secondary side of the plurality of pole transformers 3 installed in the specific area and transforming a high voltage from the high-voltage distribution system to a low voltage. Each of the low-voltage distribution system monitoring control devices 5 is installed. Each power conditioner 6 only receives a reactive power adjustment command from the low-voltage distribution system monitoring and control device 5 of the low-voltage distribution system to which it is connected, even if its interconnection point voltage is less than the upper limit of 214 V, power factor 1 to 0. The phase advance reactive power is output between 85.
本発明の制御アルゴリズムを以下に示す。
ある太陽光発電システムが発電可能電力ｐａｖａｉｌを出力するだけの日射を得ているが、そのパワーコンディショナ６の連系点電圧ｖｐｖが上限２１４Ｖに達したため、力率を０．８５とし、かつ発電出力（有効電力）をｐｏｐまで抑制しているとする。柱上変圧器３の一次側から当該太陽光発電システムまでのインピーダンス（二次側換算値）がｒ＋ｊｘである（ｒは抵抗分、ｘはリアクタンス分）とき、仮にこの太陽光発電システムが発電可能電力ｐａｖａｉｌを出力するまで電圧上限値を２１４Ｖから徐々に上げた場合、高圧配電系統への影響を無視すれば連系点電圧は、下記の数式１に示されるΔｖｐｖだけ上昇（二次側換算値）することになる。
A solar power generation system obtains solar radiation enough to output the power p avail that can be generated, but since the connection point voltage v pv of the power conditioner 6 has reached the upper limit of 214 V, the power factor is set to 0.85, In addition, it is assumed that the power generation output (active power) is suppressed to p op . When the impedance (secondary side conversion value) from the primary side of the pole transformer 3 to the solar power generation system is r + jx (r is a resistance component and x is a reactance component), this solar power generation system can generate power temporarily. When the voltage upper limit value is gradually increased from 214 V until the power p avail is output, if the influence on the high-voltage distribution system is ignored, the connection point voltage increases by Δv pv shown in the following formula 1 (secondary side) Conversion value).
ここに、Δｐはこの太陽光発電システムの発電出力（有効電力）の増分、Δｑはこの太陽光発電システムが出力する進相無効電力の増分である。
配電系統の電圧変動はほぼ線形なので、同じ低圧配電系統につながる複数のパワーコンディショナ６がｐａｖａｉｌを出力すると、低圧配電線路の末端の電圧はΔｖｐｖの和の分だけ上昇する。（ただし、図３のように柱上変圧器から左右両側に対称に分かれている低圧配電系統なら、Δｖｐｖの和の半分となる。）
Here, Δp is an increment of the power generation output (active power) of this solar power generation system, and Δq is an increment of the phase reactive power output by this solar power generation system.
Since the voltage fluctuation of the distribution system is almost linear, when a plurality of power conditioners 6 connected to the same low-voltage distribution system output p avail , the voltage at the end of the low-voltage distribution line increases by the sum of Δv pv . (However, in the case of a low voltage distribution system that is symmetrically divided from the pole transformer to the left and right sides as shown in FIG. 3, it is half the sum of Δv pv .)
低圧配電系統での有効・無効電力が変わらない場合、柱上変圧器３の一次電圧（二次側換算値）を下げると、低圧配電系統の線路電圧全体も同じだけ下がると近似できる。そこで、柱上変圧器３の一次電圧（二次側換算値）がこの柱上変圧器３につながるすべての太陽光発電システムの−Δｖｐｖの和の分だけ下がれば、それらの太陽光発電システムが発電可能電力ｐａｖａｉｌを出力できるようになる。 When the active / reactive power in the low-voltage distribution system does not change, it can be approximated that when the primary voltage (secondary conversion value) of the pole transformer 3 is lowered, the entire line voltage of the low-voltage distribution system is also lowered by the same amount. Therefore, if the primary voltage (secondary side converted value) of the pole transformer 3 decreases by the sum of −Δv pv of all the photovoltaic power systems connected to the pole transformer 3, those photovoltaic power systems Can output the electric power p available that can be generated.
そこで節点ｉの柱上変圧器３に設置された低圧配電系統監視制御装置４は、自身につながる低圧配電系統内の各パワーコンディショナ６からΔｖｐｖを受信し、連系自身の一次電圧の電圧低下要請値ΔＶｒｉ＝−ＧΣΔｖｐｖを高圧配電系統監視制御装置に送信する。ここにＧは柱上変圧器３の巻数比（６６００／２１０）である。
高圧配電系統監視制御装置は各低圧配電系統監視制御装置からのΔＶｒｉに応えるべく、高圧配電系統における必要な各節点ｊの無効電力調整指令値ΔＱｒｊを算出する。その方法は、線路インピーダンスから求まる感度係数を用いて各節点の無効電力変動と電圧変動の関係を表す連立方程式を最小二乗法により解くものである。
Therefore, the low-voltage distribution system monitoring and control device 4 installed in the pole transformer 3 at the node i receives Δvpv from each power conditioner 6 in the low-voltage distribution system connected to itself, and the voltage drop of the primary voltage of the interconnection itself The requested value ΔVri = −GΣΔvpv is transmitted to the high voltage distribution system monitoring and control device. Here, G is the turn ratio (6600/210) of the pole transformer 3.
The high-voltage distribution system monitoring and control device calculates a reactive power adjustment command value ΔQrj for each node j required in the high-voltage distribution system in order to respond to ΔVri from each low-voltage distribution system monitoring and control device. In this method, simultaneous equations representing the relationship between reactive power fluctuations and voltage fluctuations at each node are solved by a method of least squares using a sensitivity coefficient obtained from the line impedance.
具体的には、当該エリア内の低圧配電系統を監視制御する低圧配電系統監視制御装置の台数がＮ台で、そのうちΔＶｒｉが零でない（出力抑制制御を行っている太陽光発電システムがつながっている）低圧配電系統監視制御装置の台数がｍ台（ｍ≦Ｎ）、また進相無効電力を増やせる（力率が０．８５になっていない）パワーコンディショナ６が１台でも連系している低圧配電系統を監視している低圧配電系統監視制御装置の台数がｎ台（ｎ≦Ｎ）であるとき、連立方程式は、次の数式２となる。
ここに、ａｉｊは節点ｊの無効電力が増えたときに節点ｉの電圧がどれだけ高くなるかを表す感度係数であり、上記特許文献３の式９〜１１におけるｑｉｊに相当する。
ｍ＝ｎであれば、解く変数の数と方程式の本数が同じなので、上記の数式２を解くことでΔＱｒｊを算出できるが、それ以外では解くことができない。そこで、最小二乗法により、数式２にΔＱｒｊを代入したときの値をΔＶｐｉとしたとき、ΔＶｐｉとΔＶｒｉの差の二乗和が最小になるように、ΔＱｒｊを算出する。ただし、これにより解いた解は、例えば節点ｊのΔＱｒｊは正値だが、隣の節点ｊ＋１のΔＱｒ（ｊ＋１）は負値となり、お互いに無効電力を打ち消してしまうような、実用上好ましくない結果を算出する可能性がある。そこで、最小二乗法における誤差の二乗和Ｕの式に、節点間の進相無効電力出力のばらつきを低減する項を加える。具体的には、誤差の二乗和Ｕの式を、次の数式３のようにする。
If m = n, since the number of variables to be solved and the number of equations are the same, ΔQ rj can be calculated by solving Equation 2 above, but otherwise it cannot be solved. Therefore, by the least squares method, when the value obtained by substituting Delta] Q rj in Equation 2 was [Delta] V pi, as the square sum of the difference [Delta] V pi and [Delta] V ri is minimized, to calculate the Delta] Q rj. However, the solution solved by this is not practically preferable, for example, ΔQ rj at node j is a positive value, but ΔQ r (j + 1) at adjacent node j + 1 becomes a negative value, which cancels each other's reactive power. The result may be calculated. Therefore, a term for reducing variation in the fast reactive power output between nodes is added to the formula of the square sum of errors U in the least square method. Specifically, the equation of the sum of squared errors U is expressed as the following Equation 3.
ここに、Ｑｒｊは無効電力調整指令を送る直前の、節点ｊにつながる低圧配電系統につながるすべてのパワーコンディショナ６が出力している進相無効電力の和、Ｓｊは節点ｊにつながる低圧配電系統につながるパワーコンディショナ６の総容量であり、ｂは正数である。上記数式３において、右辺第一項がΔＶｐｉとΔＶｒｉの差の二乗和を表しており、右辺第二項は節点ｊにおけるパワーコンディショナ６からの進相無効電力の和の容量比（Ｑｒｊ＋ΔＱｒｊ）／Ｓｊの、無効電力調整可能な全節点の進相無効電力の容量比の平均値からのずれに関連している。上記数式３のＵをΔＱｒｊで偏微分すると、ΔＱｒｊに関するｎ本の連立方程式が得られるので、それを解くことでΔＱｒｊを得る。 Here, Q rj is the sum of the phase reactive power output from all the power conditioners 6 connected to the low voltage distribution system connected to the node j immediately before sending the reactive power adjustment command, and S j is the low voltage connected to the node j. This is the total capacity of the power conditioner 6 connected to the power distribution system, and b is a positive number. In Equation 3, the first term on the right side represents the sum of squares of the difference between ΔV pi and ΔV ri , and the second term on the right side represents the capacity ratio (Q of the sum of the fast reactive power from the power conditioner 6 at the node j. rj + ΔQ rj ) / S j is related to the deviation from the average value of the capacity ratio of the fast reactive power of all the nodes capable of adjusting reactive power. When partially differentiated by Delta] Q rj the U of the equation 3, the simultaneous equations of n book on Delta] Q rj is obtained, to obtain a Delta] Q rj by solving it.
高圧配電系統監視制御装置２は、本計算により得られた無効電力調整指令値ΔＱｒｊに１未満の正数であるｃを乗じた値を、該当する各低圧配電系統監視制御装置５に送る。ｃを乗じる理由は、急激な無効電力の変動を避けるためである。各低圧配電系統監視制御装置は当該低圧配電系統が出力すべき無効電力調整指令値ｃΔＱｒｊを高圧配電系統監視制御装置より受け取った後、自分につながる太陽光発電システムｋに無効電力変化量ΔｑｋをｃΔＱｒｊ＝ΣΔｑｋとなるように割り振り、それらにΔｑｋを指令値として送る。以上を繰り返すことで、電圧上昇を抑制し、それにより可能な限り各太陽光発電システムの出力抑制を減らすことができる。繰り返しの中で、当該エリアに出力抑制制御をしているパワーコンディショナ６がなくｍ＝０の場合は、Ｑｒｊを徐々に絞るように指令する。これにより、無駄な無効電力出力を防止できる。 The high voltage distribution system monitoring and control device 2 sends a value obtained by multiplying the reactive power adjustment command value ΔQ rj obtained by this calculation by c, which is a positive number less than 1, to each corresponding low voltage distribution system monitoring and control device 5. The reason for multiplying by c is to avoid sudden reactive power fluctuations. Each low-voltage distribution system monitoring and control device receives the reactive power adjustment command value cΔQ rj to be output from the low-voltage distribution system from the high-voltage distribution system monitoring and control device, and then the reactive power change amount Δq k to the photovoltaic power generation system k connected to itself. the allocation to the cΔQ rj = ΣΔq k, and sends them to the [Delta] q k as a command value. By repeating the above, it is possible to suppress voltage increase and thereby reduce output suppression of each photovoltaic power generation system as much as possible. In the repetition, when there is no power conditioner 6 that performs the output suppression control in the area and m = 0, a command is given to gradually reduce Q rj . Thereby, useless reactive power output can be prevented.
各低圧配電系統監視装置は当該低圧配電系統につながるパワーコンディショナ６に無効電力調整要求量を割り振る際、パワーコンディショナそれぞれに運転力率を指令値として送信する。そして、各パワーコンディショナ６は自身の運転力率が上記指令値以下となるように無効電力を出力する。力率で指定する場合、各パワーコンディショナ６の容量（定格出力）が異なっても、その容量に比例した進相無効電力を割り振ることになる。無効電力の出力はパワーコンディショナ６の電流を増やすことになり、装置での電力損失が増えるが、容量が大きいことは発電による有効電力の逆潮流も大きいので、公平な無効電力分配方法である。 Each low-voltage distribution system monitoring device transmits a driving power factor as a command value to each power conditioner when allocating a reactive power adjustment request amount to the power conditioner 6 connected to the low-voltage distribution system. Then, each power conditioner 6 outputs reactive power so that its driving power factor becomes equal to or less than the command value. When designating by the power factor, even if the capacity (rated output) of each power conditioner 6 is different, phase reactive power proportional to the capacity is allocated. The reactive power output increases the current of the power conditioner 6 and the power loss in the device increases. However, the large capacity means that the reverse flow of the active power due to the power generation is large, and this is a fair reactive power distribution method. .
想定したエリアにおいて、上記の制御を行った場合について数値解析を行った。その結果得られた、高圧配電系統内の各節点の電圧及び消費電力を図６に、低圧配電系統内の各連系点における電圧（分解能０．１Ｖ）と発電電力と力率を図７に示す。
図６の電力消費において、柱上変圧器３を介して低圧配電系統がつながるすべての節点で逆潮流電力が８１ｋＷとなっている。このことは、これらの節点につながる低圧配電系統内において、すべてのパワーコンディショナ６が出力抑制制御を行っていないことを示している。
Numerical analysis was performed for the case where the above control was performed in the assumed area. The resulting voltage and power consumption at each node in the high-voltage distribution system are shown in FIG. 6, and the voltage (resolution 0.1 V), generated power and power factor at each interconnection point in the low-voltage distribution system are shown in FIG. Show.
In the power consumption of FIG. 6, the reverse power flow is 81 kW at all nodes connected to the low voltage distribution system via the pole transformer 3. This indicates that all the power conditioners 6 are not performing the output suppression control in the low voltage distribution system connected to these nodes.
図７より、各低圧配電系統において、連系点４以下につながっているパワーコンディショナ６はすべて、連系点電圧が２１４Ｖ以下であるが、すべて力率１未満で、同じ低圧配電系統内のものはすべて同じ力率で運転している。連系点５以上につながっているパワーコンディショナ６の中には、連系点電圧が２１４Ｖに達しているものがあり、同じ低圧配電系統の連系点４以下のものより低い力率で運転しているものがあるが、すべて１．８ｋＷを出力している。また、すべてのパワーコンディショナ６が力率０．８５以上で運転している。
このように本発明の制御法では、自身の連系点電圧が上限値に達していないパワーコンディショナ６も進相無効電力を適切に出力することで、配電系統全体の電圧を適切に調節できる。これにより、すべての太陽光発電システムが出力抑制制御を行わず、太陽電池パネル群への日射に応じた出力できる最大電力を発電できる。
From FIG. 7, in each low-voltage distribution system, all power conditioners 6 connected to the connection point 4 or lower have a connection point voltage of 214 V or less, but all have a power factor of less than 1 and are in the same low-voltage distribution system. Everything is driving at the same power factor. Some power conditioners 6 connected to the connection point 5 or higher have a connection point voltage of 214 V, and operate at a power factor lower than that of the connection point 4 or less of the same low-voltage distribution system. All of them are outputting 1.8kW. Moreover, all the power conditioners 6 are operating at a power factor of 0.85 or more.
Thus, according to the control method of the present invention, the power conditioner 6 whose own interconnection point voltage has not reached the upper limit value can also appropriately adjust the voltage of the entire distribution system by appropriately outputting the phase advance reactive power. . Thereby, all the photovoltaic power generation systems do not perform output suppression control, and can generate the maximum power that can be output according to solar radiation to the solar cell panel group.
なお、本発明の高圧・低圧配電系統電圧調節システムを実施するにあたり、各太陽光発電システムがどの柱上変圧器の下の低圧配電系統につながっているのかという情報及び双方向の通信が必要である。低圧配電系統監視制御装置５とパワーコンディショナ６との双方向通信手段は、既存のネットワークがあればこれを活用すればよいが、有線の情報通信線を新規に敷設しない手段を採用すれば、情報通信のためのコストを抑えることができる。そのような手段としては、電磁波による無線通信と、図１の破線でしめされるように、電力線搬送通信(PLC:Power Line Communication)がある。電力線搬送通信を用いた場合、電力線搬送通信で用いる周波数が電力系統の商用周波数（５０Ｈｚまたは６０Ｈｚ）よりも高いため、柱上変圧器を通過すると信号が著しく減衰する。このため、電力線搬送通信を用いれば、パワーコンディショナ６からの通信信号は、該パワーコンディショナ６がつながっている低圧配電系統と直接つながる柱上変圧器３のみが、十分な強度で通信信号を得ることができる。このため、各パワーコンディショナ６がどの柱上変圧器３の下の低圧配電系統につながっているのかを容易に判別できる。 In order to implement the high-voltage / low-voltage distribution system voltage regulation system of the present invention, information on which solar power generation system is connected to the low-voltage distribution system under which pole transformer and bidirectional communication are necessary. is there. The bidirectional communication means between the low-voltage distribution system monitoring control device 5 and the power conditioner 6 may be utilized if there is an existing network, but if a means that does not newly lay a wired information communication line is adopted, Costs for information communication can be reduced. As such means, there are wireless communication using electromagnetic waves and power line communication (PLC) as shown by a broken line in FIG. When the power line carrier communication is used, the frequency used in the power line carrier communication is higher than the commercial frequency (50 Hz or 60 Hz) of the power system, so that the signal is significantly attenuated when passing through the pole transformer. For this reason, if power line carrier communication is used, the communication signal from the power conditioner 6 can be transmitted with sufficient strength only by the pole transformer 3 directly connected to the low voltage distribution system to which the power conditioner 6 is connected. Can be obtained. For this reason, it is possible to easily determine which power transformer 6 is connected to which low voltage distribution system under the pole transformer 3.
以上説明したように、本発明によれば、電力潮流を直接扱うＳＶＲ、ＳＶＣ、ＬＢＣといったハードウェアを追加・新設することなく、電力線搬送通信、電磁波による無線通信、あるいは既存のネットワークを活用して、パワーコンディショナや同期発電機により系統連系する分散型電源の無効電力調整機能を最大限に有効活用して、配電系統全体の電圧を適切に制御することができるので、今後広い普及が予測される、太陽光発電システム等の自家発電設備を配電系統に連系した特定エリアの配電系統において、全体のエネルギー効率を抜本的に高める高圧・低圧配電系統電圧調節システムとして広く作用されることが期待される。 As described above, according to the present invention, power line carrier communication, radio communication using electromagnetic waves, or existing networks can be used without adding or newly installing hardware such as SVR, SVC, and LBC that directly handle power flow. Because the reactive power adjustment function of the distributed power supply that is connected to the grid by power conditioners and synchronous generators can be used to the maximum extent, the voltage of the entire distribution system can be controlled appropriately, so widespread use is expected in the future In a distribution system in a specific area where private power generation equipment such as a photovoltaic power generation system is connected to the distribution system, it can be widely used as a voltage regulation system for high and low voltage distribution systems that drastically enhances the overall energy efficiency. Be expected.
１ 高圧配電線
２ 高圧配電系統監視制御装置
３ 柱上変圧器
４ 低圧配電線
５ 低圧配電系統監視制御装置
６ パワーコンディショナ
DESCRIPTION OF SYMBOLS 1 High voltage distribution line 2 High voltage distribution system monitoring and control apparatus 3 Pole transformer 4 Low voltage distribution line 5 Low voltage distribution system monitoring control apparatus 6 Power conditioner
Claims (6)
当該特定地域の高圧配電系統を監視制御する高圧配電系統監視制御装置と、
当該特定地域内に設置され、前記高圧配電系統からの高電圧を低電圧に変圧する複数台の変圧器と、
該変圧器の２次側に接続された低圧配電系統を監視制御する低圧配電系統監視制御装置と、
前記分散型電源毎に配備され、無効電力を制御することにより該分散型電源の連系点電圧を制御するパワーコンディショナとからなり、
前記高圧配電系統監視制御装置及び前記低圧配電系統監視制御装置並びに前記パワーコンディショナは、それぞれ双方向通信手段により接続されており、
前記パワーコンディショナは、それぞれの連系点電圧を前記低圧配電系統監視制御装置に伝達し、
かつ前記低圧配電系統監視制御装置は、各パワーコンディショナの連系点電圧が規定の上限値以下、かつ、その運転力率が規定の下限値以上を維持できるよう、該連系点電圧に基づいて、当該低圧配電系統に属する前記変圧器毎に一次電圧調整要求量ΔＶｒｉ（ｉ＝１、・・・、Ｎ）を演算して前記高圧配電系統監視制御装置に送信するとともに、
前記高圧配電系統監視制御装置は、該一次電圧調整要求量に基づいて前記低圧配電系統監視制御装置のそれぞれに当該低圧配電系統における無効電力調整指令値ΔＱｒｊ（ｊ＝１、・・・、Ｎ）を送信し、
前記低圧配電系統監視装置のそれぞれは、当該低圧配電系統に割り当てられた無効電力調整指令値ΔＱｒｊに基づいて当該低圧配電系統につながる各パワーコンディショナに無効電力調整要求量を割り振ることを特徴とする高圧・低圧配電系統電圧調節システム。 In the distribution system in a specific area where multiple distributed power sources are connected to the low-voltage distribution system,
A high voltage distribution system monitoring and control device for monitoring and controlling the high voltage distribution system in the specific area;
A plurality of transformers installed in the specific area and transforming a high voltage from the high voltage distribution system into a low voltage;
A low-voltage distribution system monitoring and control device for monitoring and controlling the low-voltage distribution system connected to the secondary side of the transformer;
A power conditioner that is arranged for each distributed power source and controls the interconnection point voltage of the distributed power source by controlling reactive power;
The high-voltage distribution system monitoring and control device, the low-voltage distribution system monitoring and control device, and the power conditioner are each connected by bidirectional communication means,
The power conditioner transmits each interconnection point voltage to the low-voltage distribution system monitoring and control device,
The low-voltage distribution system monitoring and control device is based on the interconnection point voltage so that the interconnection point voltage of each power conditioner can be maintained below the specified upper limit value and the operating power factor can be maintained above the specified lower limit value. Calculating a primary voltage adjustment request amount ΔVri (i = 1,..., N) for each of the transformers belonging to the low-voltage distribution system, and transmitting the calculated voltage to the high-voltage distribution system monitoring and control device.
The high-voltage distribution system monitoring and control device sends a reactive power adjustment command value ΔQrj (j = 1,..., N) in the low-voltage distribution system to each of the low-voltage distribution system monitoring and control devices based on the primary voltage adjustment request amount. Send
Each of the low-voltage distribution system monitoring devices allocates a reactive power adjustment request amount to each power conditioner connected to the low-voltage distribution system based on the reactive power adjustment command value ΔQrj assigned to the low-voltage distribution system. High and low voltage distribution system voltage regulation system.
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