JP5654866B2 - Reverse flow assumption method - Google Patents
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- 238000000034 method Methods 0.000 title claims description 48
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- 238000007726 management method Methods 0.000 description 18
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Description
本発明は、低圧配電系統における太陽光発電設備からの逆潮流を考慮した変圧器（柱上変圧器などの配電用変圧器）の負荷管理（最大負荷電流の想定）を行うための逆潮流想定方法に関するものである。 The present invention is a reverse power flow assumption for load management (assuming maximum load current) of a transformer (distribution transformer such as a pole transformer) in consideration of a reverse flow from a photovoltaic power generation facility in a low voltage distribution system. It is about the method.
従来、柱上変圧器などの負荷管理手法としては、非特許文献１に記載されているように、契約容量から実負荷の最大電流値を想定するｋＷ法や、使用電力量から実負荷の最大電流値を想定するｋＷｈ法が知られている。 Conventionally, as described in Non-Patent Document 1, as a load management method for pole transformers, the kW method that assumes the maximum current value of the actual load from the contracted capacity, or the maximum of the actual load from the amount of power used A kWh method that assumes a current value is known.
また、特許文献１には、分散電源の存在や各種配電系統機器の非線形性を考慮した的確な系統状態の推定を可能にする方法として、系統側及び分散電源側からの発電電力の合計値を各負荷の契約設備容量による按分比に従って配分することにより負荷電力初期値を算出するステップと、負荷電力初期値を用いて潮流計算を実行し状態変数としての分散電源出力及び負荷電力に対してこれらを解として生成させる各上下限値を計算するステップと、各上下限値による制約条件を満たし、かつ、分散電源出力及び負荷電力の観測値と観測点における計算値との誤差を最小化する目的関数を充足するような系統状態をＰＳＯにより求めて系統内各地点の電圧・電流を推定するステップとを有する方法が記載されている。 Patent Document 1 discloses a total value of generated power from the system side and the distributed power source side as a method that enables accurate estimation of the system state in consideration of the existence of the distributed power source and the nonlinearity of various power distribution system devices. A step of calculating an initial load power value by allocating according to a prorated ratio according to the contracted capacity of each load, and a power flow calculation using the initial load power value, and executing these calculations for distributed power output and load power as state variables. The step of calculating each upper and lower limit value that is generated as a solution, and the purpose of satisfying the constraint condition by each upper and lower limit value and minimizing the error between the observed value of the distributed power supply output and load power and the calculated value at the observation point And calculating a system state satisfying the function by PSO and estimating a voltage / current at each point in the system.
ところで、前述した技術については、太陽光発電設備などの分散電源が系統に連系された場合など、逆潮流、すなわち、需要家から変圧器に流れる電流の想定への適用検証事例がなく、その適用可否は不明である。また、逆潮流を簡易に想定する手法も一般に示されていない。 By the way, there is no application verification example for the assumption of the reverse power flow, that is, the current flowing from the consumer to the transformer, such as when the distributed power source such as the photovoltaic power generation facility is connected to the grid, etc. Applicability is unknown. Also, there is no general method for easily assuming reverse power flow.
そこで、本発明は、上述した従来の系統状態の想定方法に鑑みて提案されたものであって、太陽光発電設備からの逆潮流を考慮した変圧器の負荷管理（最大負荷電流の想定）を簡易かつ高い精度で実施することができる逆潮流想定方法を提供することを目的とする。 Therefore, the present invention has been proposed in view of the above-described conventional method for estimating the system state, and the load management of the transformer (assuming the maximum load current) in consideration of the reverse power flow from the photovoltaic power generation facility. An object is to provide a reverse power flow estimation method that can be implemented simply and with high accuracy.
本発明者らは、太陽光発電設備の連系するバンク（１台の変圧器から低圧配電系統を通じて分岐接続される全ての電気設備までをひとまとめにした変圧器の電力供給範囲を表す単位）における変圧器２次（低圧）側直下にて測定した実測電圧と実測逆潮流（太陽光発電設備から低圧配電系統を通じて変圧器に流れる電流）のデータを元に、「最大電圧−逆潮流」，「電圧−最大逆潮流」，「逆潮流最大度数時における平均電圧」，「最大逆潮流−発電導入率」，「最大逆潮流−逆潮流電力量」などの相関や傾向について、季節別や時間帯別に分析した。 The present inventors in a bank (a unit representing a power supply range of a transformer collectively from one transformer to all electric facilities branched and connected through a low-voltage distribution system) connected to a photovoltaic power generation facility Based on the measured voltage measured directly under the transformer secondary (low voltage) side and the measured reverse power flow (current flowing from the photovoltaic power generation facility to the transformer through the low voltage distribution system), “maximum voltage minus reverse power flow”, “ Regarding the correlations and trends such as “Voltage-Maximum reverse power flow”, “Average voltage at maximum reverse power flow”, “Maximum reverse power flow-Power generation introduction rate”, “Maximum reverse power flow-Reverse power flow energy”, by season and time zone Separately analyzed.
その結果、図１（ａ）に示す「想定逆潮流−発電導入率（発電パネル容量／契約容量）」（ｋＷ法に相当）と、図１（ｂ）に示す「想定逆潮流−逆潮流電力量（発電量−自己消費量）」（ｋＷｈ法に相当）において、高い相関性が確認され、この二つの手法により逆潮流を想定する計算式を導くことができることが判明した。 As a result, “assumed reverse power flow—power generation introduction rate (power generation panel capacity / contract capacity)” (corresponding to the kW method) shown in FIG. 1A and “assumed reverse power flow—reverse power flow” shown in FIG. A high correlation was confirmed in “quantity (power generation amount−self-consumption amount)” (corresponding to the kWh method), and it was found that a calculation formula assuming reverse power flow can be derived by these two methods.
すなわち、第１の発明（請求項１記載の発明）に係る逆潮流想定方法は、測定対象となる逆潮流電力量の異なるバンクを選定し、これら測定対象となるバンクにおける変圧器２次側直下にて逆潮流を測定し、これら実測データを記録し、実測データを収集する第１のステップと、第１のステップで収集された実測データに基づいて、最大逆潮流と逆潮流電力量との分散をグラフ上にプロットする第２のステップと、第２のステップで求められたプロットに対する近似曲線、または、近似直線を引き相関近似式を求める第３のステップと、第３のステップで求められた相関近似式に基づいて、最大逆潮流と逆潮流電力量の分散から相関性の係数を求め、その係数により相関近似式を評価する第４のステップと、第４のステップで評価された相関近似式に、測定対象となるバンクとは別の予測したいバンクの想定用逆潮流電力量を入力し、その予測したいバンクにおける最大逆潮流を想定する第５のステップとを有することを特徴とするものである。 That is, the backward flow assumption method according to the first invention (the invention according to claim 1) is to select the backward flow power amount of different banks to be measured, the transformer secondary in these measurements subject to bank measuring the backward flow on the side directly below, records these measured data, a first step to gather the measurement data, based on the measured data collected in the first step, the maximum backward flow and the backward flow power A second step for plotting the variance with the quantity on the graph, a third step for obtaining a correlation approximation expression by drawing an approximate curve or an approximate straight line for the plot obtained in the second step, and a third step Based on the correlation approximation formula obtained in step 4, the correlation coefficient is obtained from the variance of the maximum reverse flow and the reverse power flow, and the correlation approximation formula is evaluated based on the coefficient, and the evaluation is performed in the fourth step. Correlation A similar type, enter the assumptions for the backward flow power amount of another prediction want bank the measurement subject to bank, and having a fifth step of assuming a maximum backward flow in the prediction want bank Is.
また、第２の発明（請求項２記載の発明）に係る逆潮流想定方法は、測定対象となる発電導入率の異なるバンクを選定し、これら測定対象となるバンクにおける変圧器２次側直下にて逆潮流を測定し、これら実測データを記録し、実測データを収集する第１のステップと、第１のステップで収集された実測データに基づいて、最大逆潮流と発電導入率との分散をグラフ上にプロットする第２のステップと、第２のステップで求められたプロットに対する近似曲線、または、近似直線を引き相関近似式を求める第３のステップと、第３のステップで求められた相関近似式に基づいて、最大逆潮流と発電導入率の分散から相関性の係数を求め、その係数により相関近似式を評価する第４のステップと、第４のステップで評価された相関近似式に、測定対象となるバンクとは別の予測したいバンクの想定用発電導入率を入力し、その予測したいバンクにおける最大逆潮流を想定する第５のステップとを有することを特徴とするものである。 Further, the reverse flow assumption method according to the second invention (invention described in claim 2) is to select the power generation rate of introduction of different banks to be measured, the transformer in these measurements subject to bank secondary the reverse power flow measured just below, records these measured data, a first step to gather the measurement data, based on the measured data collected in the first step, the maximum backward flow and power generation introduction rate A second step of plotting the variance of the graph on the graph, a third step for obtaining a correlation approximation equation by drawing an approximation curve or an approximation line for the plot obtained in the second step, and a third step for obtaining a correlation approximation formula Based on the obtained correlation approximate expression, a correlation coefficient is obtained from the variance of the maximum reverse power flow and the power generation introduction rate, and the correlation evaluated by the fourth step is evaluated using the coefficient. the approximate expression, The bank of a constant target enter the assumptions for the generation rate of introduction of another prediction want bank, it is characterized in further comprising a fifth step of assuming a maximum backward flow at the predicted want bank.
上記第１の発明（請求項１記載の発明）や第２の発明（請求項２記載の発明）に係る逆潮流想定方法においては、太陽光発電設備が連系する変圧器の最大逆潮流を想定することが可能となり、以下の効果が期待できる。 In the reverse power flow estimation method according to the first invention (the invention described in claim 1) or the second invention (the invention described in claim 2), the maximum reverse power flow of the transformer to which the photovoltaic power generation facility is connected is calculated. The following effects can be expected.
すなわち、逆潮流が変圧器の現状の管理値（バンクの利用率から決まる変圧器の想定電流値）を上回り、過負荷による変圧器の焼損が起きないかを確認することができる。また、変圧器の負荷管理手法として、ｋＷ法やｋＷｈ法の適用性の可否を判断できる。さらに、変圧器の取替え時などに適正容量を判断できる。そして、計算結果を高圧換算することで、変圧器から配電系統（高圧）への逆潮流を計算できる。 That is, it can be confirmed whether the reverse power flow exceeds the current management value of the transformer (the assumed current value of the transformer determined from the bank utilization rate), and the transformer is not burned due to overload. Moreover, the applicability of the kW method or the kWh method can be determined as a transformer load management method. Furthermore, it is possible to determine the appropriate capacity when replacing the transformer. And the reverse power flow from a transformer to a power distribution system (high voltage) can be calculated by converting a calculation result into a high voltage.
すなわち、本発明によれば、太陽光発電設備からの逆潮流を考慮した変圧器の負荷管理（最大負荷電流の想定）を簡易かつ高い精度で実施することができる逆潮流想定方法を提供することができるものである。 That is, according to the present invention, there is provided a reverse power flow estimation method capable of easily and highly accurately performing transformer load management (assuming maximum load current) in consideration of reverse power flow from a photovoltaic power generation facility. It is something that can be done.
以下、本発明に係る逆潮流想定方法の実施の形態について、図面を参照しながら詳細に説明する。 Hereinafter, embodiments of a reverse power flow estimation method according to the present invention will be described in detail with reference to the drawings.
〔変圧器の負荷管理への影響〕
（１）管理値に対する最大値（電流・逆潮流）
図２は、管理値（バンクの利用率から決まる変圧器の想定電流値）に対する測定期間中の同一時刻における最大値（電流・逆潮流）の関係を示すグラフである。この実測バンクでは最大電流が管理値内にあることが視覚的に確認できる。同様に最大逆潮流（絶対値）も管理値内にあり、逆潮流の最大値は電流の最大値よりも低いことが確認できる。
（２）最大逆潮流と発電導入率との相関分析
最大逆潮流と発電導入率（パネル容量／契約容量）との関係を月別・季節別に検証した。
[Impact on transformer load management]
(1) Maximum value for control value (current / reverse power flow)
FIG. 2 is a graph showing the relationship of the maximum value (current / reverse power flow) at the same time during the measurement period with respect to the management value (assumed current value of the transformer determined from the bank utilization rate). In this measured bank, it can be visually confirmed that the maximum current is within the control value. Similarly, the maximum reverse flow (absolute value) is also within the control value, and it can be confirmed that the maximum reverse flow is lower than the maximum current.
(2) Correlation analysis between maximum reverse power flow and power generation introduction rate The relationship between maximum reverse power flow and power generation introduction rate (panel capacity / contract capacity) was verified by month and season.
図３は、指定月における最大逆潮流と発電導入率の関係を月別に示したグラフである。
図３に示すように、この実測データにおいては決定係数（Ｒ２：相関係数の２乗）の最も高い８月が０．８０１７であり、相関性があることが確認できる。
FIG. 3 is a graph showing the relationship between the maximum reverse power flow and the power generation introduction rate for each specified month.
As shown in FIG. 3, in this measured data, August, which has the highest coefficient of determination (R 2 : square of correlation coefficient), is 0.8017, and it can be confirmed that there is a correlation.
また、図４は季節別の最大逆潮流と発電導入率との関係を示すグラフである。 FIG. 4 is a graph showing the relationship between seasonal maximum reverse power flow and power generation introduction rate.
図４に示すように、季節別の関係では秋季および冬季に比べて、春季および夏季に相関性が高く、近似曲線の傾きが大きいのは、日射時間が長いことが影響していると考えられる。 As shown in FIG. 4, in terms of seasonal relationships, the correlation between spring and summer is higher than that in autumn and winter, and the slope of the approximate curve is large. .
（３）最大電流と電力量との相関分析
変圧器の負荷想定には、前述したように、契約容量から簡易に負荷想定ができるｋＷ法と、実際に需要家が使用した電力量を基に高精度の負荷想定が可能と言われているｋＷｈ法の負荷管理手法がある。
(3) Correlation analysis between maximum current and electric energy Transformer load assumption is based on the kW method that allows simple load assumption from contracted capacity and the electric energy actually used by consumers as described above. There is a load management method of the kWh method that is said to be capable of assuming a load with high accuracy.
このうち、ｋＷｈ法では、最大電流と電力量の関係から負荷想定を行っているが、最大電流は、契約種別や負荷、需要家のライフスタイルなどによって、その使用時間帯が異なり、電力量は負荷設備の稼働率によって影響を受ける。 Of these, the kWh method assumes the load from the relationship between the maximum current and the amount of power, but the maximum current varies depending on the contract type, load, consumer lifestyle, etc. It is affected by the operating rate of the load equipment.
このことから、ｋＷｈ法を太陽光発電設備が連系するバンクに適用する場合において、より高精度な負荷想定をするには、最大電流−電力量の傾き（負荷想定曲線）への影響を考慮することが望ましい。 Therefore, when applying the kWh method to a bank where photovoltaic power generation facilities are connected, in order to make a more accurate load assumption, consider the effect on the slope of the maximum current-electric energy (load assumption curve). It is desirable to do.
そこで、実測最大電流と実測電流×実測電圧から求めた電力量から、時間帯別、季節別に確認できる分布を作成し、負荷想定への影響を検証した。 Therefore, a distribution that can be confirmed by time zone and season was created from the amount of power obtained from the measured maximum current and measured current x measured voltage, and the impact on load assumption was verified.
図５は、太陽光発電設備が連系するバンクにおける時間帯別の最大電流と電力量との関係を示すグラフである。 FIG. 5 is a graph showing the relationship between the maximum current and the amount of power for each time zone in the bank where the photovoltaic power generation facilities are linked.
図５に示すように、「深夜時間帯」における近似曲線の傾きと、「全日」におけるその傾きと、「逆潮流」の傾きでは、大きく異なっていることが確認できる。このことから、変圧器の負荷想定は時間帯あるいは逆潮流と区別して行うことが望ましい。 As shown in FIG. 5, it can be confirmed that the slope of the approximate curve in the “midnight time zone”, the slope in “all day”, and the slope of “reverse flow” are greatly different. For this reason, it is desirable to estimate the load of the transformer separately from the time zone or reverse power flow.
図６は、図５の「逆潮流」のみを抽出した月別のグラフである。
図６に示すように、この実測データにおいては決定係数（Ｒ２：相関係数の２乗）の最も高い１０月が０．９６６６であり、高い相関性があることが確認できる。
FIG. 6 is a graph for each month in which only “reverse power flow” in FIG. 5 is extracted.
As shown in FIG. 6, in this actual measurement data, October, which has the highest determination coefficient (R 2 : square of correlation coefficient), is 0.9666, and it can be confirmed that there is a high correlation.
図７は、季節別の最大逆潮流と逆潮流電力量との関係を示すグラフである。 FIG. 7 is a graph showing the relationship between the seasonal maximum reverse flow and the reverse flow power amount.
図７に示すように、この実測データでは何れの季節においても高い相関性が確認できる。 As shown in FIG. 7, this measured data can confirm high correlation in any season.
図８は、太陽光発電設備が連系するバンクにおける昼間時間帯の実測最大電流と電力量の関係を示すグラフである。 FIG. 8 is a graph showing the relationship between the measured maximum current and the amount of power during the daytime period in the bank where the photovoltaic power generation facilities are connected.
図８に示す「昼間時間帯」の近似曲線は、太陽光発電設備が連系するバンクにおける電力量を用いた負荷想定（ｋＷｈ法）の近似式に相当する。
本発明の検証に用いた実測データは、逆潮流の測定が可能な測定器を使用したものであるが、仮に逆潮流測定に対応しない測定器を使用した場合、電流方向（プラス・マイナス）の判断ができず電流（逆潮流）値は絶対値となり、電流と逆潮流との区別がつかない。しかし、電流方向に関係なく逆潮流も変圧器の負荷電流であると考えれば、電流（逆潮流を含む）の絶対値を測定して導いた近似式を使用して太陽光発電設備の連系するバンクの負荷想定（最大電流値）も可能と考える。
The approximate curve of “daytime time zone” shown in FIG. 8 corresponds to an approximate expression of load assumption (kWh method) using the amount of power in the bank where the photovoltaic power generation facilities are connected.
The actual measurement data used for the verification of the present invention uses a measuring device that can measure reverse power flow, but if a measuring device that does not support reverse power flow measurement is used, the current direction (plus or minus) It cannot be determined and the current (reverse power flow) value is an absolute value, and the current and the reverse power flow cannot be distinguished. However, if the reverse power flow is considered to be the load current of the transformer regardless of the current direction, it is connected to the photovoltaic power generation system using an approximate expression derived by measuring the absolute value of the current (including the reverse power flow). It is considered possible to assume the load of the bank (maximum current value).
〔電圧−逆潮流の相関分析〕
（１）逆潮流時の電圧度数分布
図９は、逆潮流時における電圧の度数分布と累積度数を示すグラフである。
この実測データにおいて、逆潮流時の電圧は２０６〜２１８Ｖに分布しており、２１１Ｖ付近の度数が大きくなっていることが確認できる。
（２）最大電圧と逆潮流との相関
逆潮流発生時における最大電圧と、同時刻での逆潮流との関係を分布グラフにより月別・季節別に検証した。
図１０は、指定月の最大電圧と逆潮流との関係を示すグラフである。
[Correlation analysis of voltage-reverse power flow]
(1) Voltage Frequency Distribution During Reverse Power Flow FIG. 9 is a graph showing the voltage frequency distribution and cumulative frequency during reverse power flow.
In this measured data, it can be confirmed that the voltage during reverse power flow is distributed between 206 and 218V, and the frequency near 211V is increased.
(2) Correlation between maximum voltage and reverse power flow The relationship between the maximum voltage at the time of reverse power flow and the reverse power flow at the same time was verified monthly and seasonally using a distribution graph.
FIG. 10 is a graph showing the relationship between the maximum voltage and reverse power flow for a specified month.
一般に系統電圧が高いと逆潮流しなくなることが懸念されるが、変圧器２次側直下における潮流可能な最大電圧を確認することができる。 In general, if the system voltage is high, there is a concern that reverse power flow will not occur, but the maximum voltage that can be flowed directly under the transformer secondary side can be confirmed.
図１１は、季節別の最大電圧と逆潮流との関係を示すグラフである。 FIG. 11 is a graph showing the relationship between the seasonal maximum voltage and the reverse power flow.
図１１に示すように、季節別の関係では決定係数（Ｒ２）は何れの季節においても０．１以下であり、相関性は極めて低いといえる。 As shown in FIG. 11, in the seasonal relationship, the coefficient of determination (R 2 ) is 0.1 or less in any season, and it can be said that the correlation is extremely low.
（３）電圧と最大逆潮流との相関
最大逆潮流発生時における電圧と最大逆潮流との関係を分布グラフにより月別・季節別に検証した。
図１２は、指定月の電圧と最大逆潮流との関係を示すグラフである。
(3) Correlation between voltage and maximum reverse power flow The relationship between the voltage and the maximum reverse power flow at the time of maximum reverse power flow was verified monthly and seasonally using a distribution graph.
FIG. 12 is a graph showing the relationship between the voltage in the specified month and the maximum reverse power flow.
図１２に示すように、この実測データにおいての最大潮流は、−８７．０Ａ（８月）が確認された。 As shown in FIG. 12, the maximum tidal current in this measured data was confirmed to be -87.0A (August).
図１３は、季節別の電圧と最大逆潮流との関係を示すグラフである。 FIG. 13 is a graph showing the relationship between seasonal voltage and maximum reverse power flow.
図１３に示すように、季節別の関係では決定係数（Ｒ２）は何れの季節においても０．１以下であり、相関性は極めて低い。また、この実測データにおいては、大半のバンクの最大逆潮流が−３５Ａ以内に集中していることが確認された。 As shown in FIG. 13, the coefficient of determination (R 2 ) is 0.1 or less in any season, and the correlation is extremely low. Moreover, in this measured data, it was confirmed that the maximum reverse power flow of most banks is concentrated within -35A.
（４）逆潮流の度数の分布
図１４は、逆潮流の度数分布と累積度数を示すグラフである。
これは逆潮流の大きいあるバンクの実測データの例であるが、逆潮流は７．５Ａの度数が最も大きくなっていることが確認できる。
（５）平均電圧と逆潮流との相関
逆潮流が最も頻繁に発生している逆潮流最大度数時における逆潮流と、その逆潮流時の平均電圧との関係を分布グラフにより月別・季節別に検証した。
(4) Frequency distribution of reverse power flow FIG. 14 is a graph showing the frequency distribution and cumulative frequency of reverse power flow.
This is an example of measured data of a bank with a large reverse power flow, but it can be confirmed that the reverse power flow has the highest frequency of 7.5A.
(5) Correlation between average voltage and reverse power flow The relationship between the reverse power flow at the maximum reverse power flow where the reverse power flow occurs most frequently and the average voltage at the reverse power flow is verified monthly and seasonally using a distribution graph. did.
図１５は、指定月の逆潮流最大度数時における平均電圧の分布を示すグラフである。
図１６は、季節別の逆潮流最大度数時における平均電圧の分布を示すグラフである。
FIG. 15 is a graph showing the distribution of the average voltage at the maximum reverse power frequency in the specified month.
FIG. 16 is a graph showing the distribution of the average voltage at the time of maximum reverse power flow by season.
図１６に示すように、季節別の関係では、決定係数（Ｒ２）は０．１以下であり、相関性は極めて低い。また、この実測データにおいては、大半のバンクの逆潮流が−１０Ａ以内に集中していることが確認された。
〔分析結果のまとめ〕
データ分析の結果から得られた成果や特徴的な内容などを以下に説明する。
As shown in FIG. 16, in the seasonal relationship, the coefficient of determination (R 2 ) is 0.1 or less, and the correlation is very low. In addition, in this measured data, it was confirmed that the reverse power flow of most banks was concentrated within -10A.
[Summary of analysis results]
The results and characteristic contents obtained from the results of data analysis are described below.
（１）変圧器の負荷管理への影響
ア．管理値に対する最大値（電流・逆潮流）
実測した最大電流は概ね変圧器の管理値（バンクの利用率から決まる変圧器の想定電流値）内に入っており、逆潮流についても管理値を超えないことが確認できた。この結果、逆潮流の影響によって変圧器が過負荷となり焼損するバンクは存在しないことを確認した。
(1) Impact on transformer load management a. Maximum value for control value (current / reverse flow)
The measured maximum current is generally within the control value of the transformer (assumed current value of the transformer determined from the bank utilization rate), and it was confirmed that the reverse power flow does not exceed the control value. As a result, it was confirmed that there was no bank where the transformer was overloaded by the influence of reverse power flow and burned out.
また、実測データが正常に測定されたものであるかどうかの評価を行うが、これは実測データの欠落・停電などのチェックの他に、この方法によりデータの妥当性を確認することができる。 In addition, whether or not the actual measurement data is normally measured is evaluated. This can check the validity of the data by this method in addition to checking the lack of the actual measurement data and the power failure.
イ．最大逆潮流と発電導入率
最大逆潮流と発電導入率の決定係数は、０．８０１７（最も高い８月）であり、高い相関性があることが確認された。
図１（ａ）は、「想定逆潮流−発電導入率（発電パネル容量／契約容量）」（ｋＷ法に相当）を示すグラフである。
このことより、図１（ａ）に示すように、最大逆潮流と発電導入率の関係から導いた近似式に想定用の発電導入率（パネル容量／契約容量）を代入することで、逆潮流の想定が可能であると考える。
A. Maximum reverse power flow and power generation introduction rate The determination coefficient of maximum reverse power flow and power generation introduction rate is 0.8017 (the highest August), confirming that there is a high correlation.
FIG. 1A is a graph showing “assumed reverse power flow-power generation introduction rate (power generation panel capacity / contract capacity)” (corresponding to the kW method).
Therefore, as shown in FIG. 1 (a), the reverse power flow is obtained by substituting the assumed power generation introduction rate (panel capacity / contract capacity) into the approximate expression derived from the relationship between the maximum reverse power flow and the power generation introduction rate. It can be assumed that
ウ．最大電流と電力量
前述したように、最大電流値と需要家の使用した電力量には相関がある（ｋＷｈ法）ことが知られているが、最大逆潮流と逆潮流電力量の関係について実測データを分析したところ、この決定係数は０．９６６６（最も高い１０月）であり、高い相関性があることが確認された。
図１（ｂ）は、「想定逆潮流−逆潮流電力量（発電量−自己消費量）」（ｋＷｈ法に相当）を示すグラフである。
このことより、図１（ｂ）に示すように、最大逆潮流と逆潮流電力量の関係から導いた近似式に想定用の逆潮流電力量を代入することで、逆潮流の想定が可能であると考える。
C. Maximum current and energy As mentioned above, it is known that there is a correlation between the maximum current value and the amount of power used by customers (kWh method), but the relationship between the maximum reverse power flow and the reverse power flow energy was measured. When the data was analyzed, this coefficient of determination was 0.9666 (the highest October), confirming that there was a high correlation.
FIG. 1B is a graph showing “assumed reverse power flow−reverse power flow amount (power generation amount−self consumption amount)” (corresponding to the kWh method).
As a result, as shown in FIG. 1 (b), reverse power flow can be assumed by substituting the reverse power flow for assumption into the approximate expression derived from the relationship between the maximum reverse power flow and the reverse power flow amount. I think there is.
エ．管理値に対する想定最大逆潮流
導かれた近似式により得た想定最大逆潮流については、逆潮流による影響を確認したいバンクの管理値（利用率）を上回っていないか、バンクの許容電流を超えて過負荷となっていないか、容量が適正であるか、評価することが望ましい。
図１７は、管理値に対する想定最大逆潮流の関係を示すグラフである。
例えば、図１７に示す予測対象バンクでは、想定最大逆潮流（絶対値）が管理値の最大値（利用率）内にあることが視覚的に確認できる。
ひと度、逆潮流の近似式が決まれば、既存の逆潮流電力量データや、太陽光導入率（パネル容量／契約容量）などを用いて特定バンクの最大逆潮流を想定し、既存の管理値（利用率）や許容電流などと照らし合わせることで、適切なバンク容量で運用できるか判断できると考える。
D. Assumed maximum reverse power flow for management value The estimated maximum reverse power flow obtained from the derived approximation formula does not exceed the management value (utilization) of the bank for which the effect of reverse power flow is to be confirmed, or exceeds the allowable current of the bank. It is desirable to evaluate whether it is overloaded or capacity is appropriate.
FIG. 17 is a graph showing the relationship of the assumed maximum reverse power flow to the management value.
For example, in the prediction target bank shown in FIG. 17, it can be visually confirmed that the assumed maximum reverse power flow (absolute value) is within the maximum value (utilization rate) of the management value.
Once the approximate formula for reverse power flow is determined, the existing reverse power flow data, solar introduction rate (panel capacity / contract capacity), etc. are used to assume the maximum reverse power flow for a specific bank and It can be judged whether it can be operated with an appropriate bank capacity by comparing with (utilization rate) and allowable current.
（２）電圧と逆潮流との相関分析
電圧と逆潮流の分析において、相関性が低いことが確認された。これは、変電所からの送り出し電圧の変動や配電系統に接続された負荷状態などにフィーダ（高圧系統）の電圧が影響を受けることによると考えられる。
(2) Correlation analysis between voltage and reverse power flow In the analysis of voltage and reverse power flow, it was confirmed that the correlation was low. This is presumably because the voltage of the feeder (high-voltage system) is affected by fluctuations in the supply voltage from the substation and the load state connected to the distribution system.
しかしながら、図１０〜図１３および図１５〜図１６の近似曲線の傾きは右下がりとなっており、逆潮流が大きくなると電圧が高くなる傾向があることが確認できた。 However, the slopes of the approximate curves in FIGS. 10 to 13 and FIGS. 15 to 16 are lower to the right, and it has been confirmed that the voltage tends to increase as the reverse power flow increases.
また、一般に系統電圧が高いと潮流しなくなることが懸念されるが、変圧器２次側直下における逆潮流可能な最大電圧を確認できた。 Moreover, in general, there is a concern that the power flow stops when the system voltage is high, but the maximum voltage that allows reverse power flow directly under the transformer secondary side was confirmed.
〔本発明に係る逆潮流想定方法の手順〕
以上のデータ分析を踏まえて、本発明に係る逆潮流想定方法は、以下の手順により実行される。
[Procedure of the reverse power flow estimation method according to the present invention]
Based on the above data analysis, the reverse power flow estimation method according to the present invention is executed by the following procedure.
図１８は、本発明に係る逆潮流想定方法の実行手順を示すフローチャートである。 FIG. 18 is a flowchart showing an execution procedure of the reverse power flow assuming method according to the present invention.
図１８のフローチャートに示すように、手順をスタートすると、ステップ１として、逆潮流の測定を行う。このステップ１では、まず、測定対象バンクを選定する。ここでバンクは、１台の変圧器から低圧配電系統を通じて分岐接続される全ての電気設備までをひとまとめにした変圧器の電力供給範囲を表す変圧器の単位をいう。次に、変圧器２次側直下にて逆潮流を測定し、その実測データを記録する。ここで、変圧器の電源側（高圧側）を１次側、負荷側（低圧側）を２次側という。また、逆潮流とは、太陽光発電設備から低圧配電系統を通じて変圧器に流れる電流をいう。そして、実測データを収集する。次に、実測データについて、正常に測定できているか、停電などがなく測定データが使用できそうかということについて、妥当性があるかを判断する。妥当性があれば、次のステップ２に進む。妥当性がなければ、ステップ１に戻る。 As shown in the flowchart of FIG. 18, when the procedure is started, reverse power flow is measured as Step 1. In step 1, first, a bank to be measured is selected. Here, the bank refers to a unit of a transformer that represents a power supply range of the transformer that collectively includes a single transformer and all the electric facilities branched and connected through the low-voltage distribution system. Next, the reverse power flow is measured directly under the transformer secondary side, and the actual measurement data is recorded. Here, the power supply side (high voltage side) of the transformer is referred to as a primary side, and the load side (low voltage side) is referred to as a secondary side. Moreover, reverse power flow means the electric current which flows into a transformer through a low voltage | pressure distribution system from photovoltaic power generation equipment. Then, actual measurement data is collected. Next, it is determined whether or not the measured data is valid with respect to whether it can be measured normally or whether the measured data can be used without a power failure. If there is validity, go to the next step 2. If there is no validity, return to Step 1.
ステップ２では、最大逆潮流と逆潮流電力量の分散をグラフ上にプロットする。ここで、逆潮流電力量は、実測した逆潮流と電圧から計算した逆潮流分の電力量をいう。 In step 2, the maximum reverse power flow and the dispersion of the reverse power flow are plotted on the graph. Here, the reverse power flow amount refers to the power amount of the reverse flow calculated from the actually measured reverse flow and voltage.
次のステップ３では、プロットに対する近似曲線を引き相関近似式を求める。この近似曲線は、データ系列の傾向や方向性を視覚的に表したものである。 In the next step 3, an approximate curve for the plot is drawn to obtain a correlation approximate expression. This approximate curve is a visual representation of the tendency and directionality of the data series.
次のステップ４では、最大逆潮流と逆潮流電力量の分散から相関性の係数を求め、その係数により相関近似式を評価する。 In the next step 4, a correlation coefficient is obtained from the dispersion of the maximum reverse power flow and the reverse power flow, and the correlation approximation formula is evaluated based on the coefficient.
そして、ステップ５では、予測したいバンクの想定用逆潮流電力量を相関近似式に入力し、そのバンクにおける最大逆潮流を想定して、終了（ストップ）する。ここで、想定用逆潮流電力量は、実測データまたは取引用計器の検針値などの既存のデータなどの電力量をいう。 In step 5, the assumed reverse flow energy of the bank to be predicted is input to the correlation approximation formula, and the maximum reverse flow in the bank is assumed, and the process is terminated. Here, the assumed reverse power flow amount refers to the amount of power such as measured data or existing data such as a meter reading value of a trading instrument.
また、本発明に係る逆潮流想定方法は、以下の手順によっても実行される。 Moreover, the reverse power flow estimation method according to the present invention is also executed by the following procedure.
図１９は、本発明に係る逆潮流想定方法の実行手順の他の例を示すフローチャートである。 FIG. 19 is a flowchart showing another example of the execution procedure of the reverse power flow assuming method according to the present invention.
図１９のフローチャートに示すように、手順をスタートすると、ステップ１として、逆潮流の測定を行う。このステップ１は、図１８に示したものと同様である。すなわち、このステップ１では、まず、測定対象バンクを選定する。次に、変圧器２次側直下にて逆潮流を測定し、その実測データを記録する。そして、実測データを収集する。
次に、実測データについて、正常に測定できているか、停電などがなく測定データが使用できそうかということについて、妥当性があるかを判断する。妥当性があれば、次のステップ２’に進む。妥当性がなければ、ステップ１に戻る。
As shown in the flowchart of FIG. 19, when the procedure is started, reverse power flow is measured as Step 1. Step 1 is the same as that shown in FIG. That is, in step 1, first, a bank to be measured is selected. Next, the reverse power flow is measured directly under the transformer secondary side, and the actual measurement data is recorded. Then, actual measurement data is collected.
Next, it is determined whether or not the measured data is valid with respect to whether it can be measured normally or whether the measured data can be used without a power failure. If there is validity, go to the next step 2 ′. If there is no validity, return to Step 1.
ステップ２’では、最大逆潮流と発電導入率の分散をグラフ上にプロットする。ここで、発電導入率は、太陽光などの発電設備容量を契約容量で割った割合を表したものをいう。 In step 2 ', the maximum reverse power flow and the dispersion of the power generation introduction rate are plotted on a graph. Here, the power generation introduction rate means a ratio obtained by dividing the power generation facility capacity such as solar light by the contracted capacity.
次のステップ３’では、プロットに対する近似曲線を引き相関近似式を求める。 In the next step 3 ', an approximate curve for the plot is drawn to obtain a correlation approximate expression.
次のステップ４’では、最大逆潮流と発電導入率の分散から相関性の係数を求め、その係数により相関近似式を評価する。 In the next step 4 ′, a correlation coefficient is obtained from the dispersion of the maximum reverse power flow and the power generation introduction rate, and the correlation approximate expression is evaluated based on the coefficient.
そして、ステップ５’では、予測したいバンクの発電導入率を相関近似式に入力し、そのバンクにおける最大逆潮流を想定して、終了（ストップ）する。 In step 5 ′, the power generation introduction rate of the bank to be predicted is input to the correlation approximation formula, and the process is terminated (stopped) assuming the maximum reverse power flow in the bank.
本発明は、太陽光発電設備からの逆潮流を考慮した変圧器の負荷管理（最大負荷電流の想定）を行うための逆潮流想定方法に適用される。 The present invention is applied to a reverse power flow estimation method for performing load management (assuming maximum load current) of a transformer in consideration of reverse power flow from a photovoltaic power generation facility.
Claims (2)
前記第１のステップで収集された実測データに基づいて、最大逆潮流と逆潮流電力量との分散をグラフ上にプロットする第２のステップと、
前記第２のステップで求められたプロットに対する近似曲線、または、近似直線を引き相関近似式を求める第３のステップと、
前記第３のステップで求められた相関近似式に基づいて、最大逆潮流と逆潮流電力量の分散から相関性の係数を求め、その係数により相関近似式を評価する第４のステップと、
前記第４のステップで評価された相関近似式に、前記測定対象となるバンクとは別の予測したいバンクの想定用逆潮流電力量を入力し、その予測したいバンクにおける最大逆潮流を想定する第５のステップと
を有することを特徴とする逆潮流想定方法。 Select a backward flow power amount of different banks to be measured, to measure the backward flow at the transformer secondary side just below the these measurements subject to bank records these measured data, to collect measured data A first step,
Based on the measured data collected in the first step, a second step of plotting the distribution of the maximum backward flow and backward flow power amount on a graph,
A third step for obtaining a correlation approximation equation by drawing an approximate curve or an approximate line with respect to the plot obtained in the second step;
A fourth step of obtaining a correlation coefficient from the maximum reverse power flow and the dispersion of the reverse power flow based on the correlation approximate expression obtained in the third step, and evaluating the correlation approximate expression based on the coefficient;
In the correlation approximation equation evaluated in the fourth step, an assumed reverse power flow amount of a bank to be predicted different from the bank to be measured is input, and the maximum reverse power flow in the bank to be predicted is assumed. 5. A reverse power flow assumption method comprising: 5 steps.
前記第１のステップで収集された実測データに基づいて、最大逆潮流と発電導入率との分散をグラフ上にプロットする第２のステップと、
前記第２のステップで求められたプロットに対する近似曲線、または、近似直線を引き相関近似式を求める第３のステップと、
前記第３のステップで求められた相関近似式に基づいて、最大逆潮流と発電導入率の分散から相関性の係数を求め、その係数により相関近似式を評価する第４のステップと、
前記第４のステップで評価された相関近似式に、前記測定対象となるバンクとは別の予測したいバンクの想定用発電導入率を入力し、その予測したいバンクにおける最大逆潮流を想定する第５のステップと
を有することを特徴とする逆潮流想定方法。 The different banks of power introduction rate to be measured selected by measuring the reverse flow at the transformer secondary side just below the these measurements subject to bank records these measured data, to gather the measurement data A first step;
A second step of plotting a variance of the maximum reverse power flow and the power generation introduction rate on a graph based on the actual measurement data collected in the first step;
A third step for obtaining a correlation approximation equation by drawing an approximate curve or an approximate line with respect to the plot obtained in the second step;
A fourth step of obtaining a correlation coefficient from the maximum reverse power flow and the dispersion of the power generation introduction rate based on the correlation approximation formula obtained in the third step, and evaluating the correlation approximation formula based on the coefficient;
In the correlation approximation expression evaluated in the fourth step, the assumed power generation introduction rate of the bank to be predicted different from the bank to be measured is input, and the maximum reverse power flow in the bank to be predicted is assumed. A reverse power flow assumption method characterized by comprising:
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| JP3929235B2 (en) * | 2000-08-01 | 2007-06-13 | 関西電力株式会社 | State estimation method in distribution system |
| JP3994910B2 (en) * | 2003-05-08 | 2007-10-24 | 株式会社日立製作所 | Electricity trading support system |
| JP4378120B2 (en) * | 2003-07-07 | 2009-12-02 | 東邦瓦斯株式会社 | Operation control system for home cogeneration system |
| JP4148208B2 (en) * | 2004-09-15 | 2008-09-10 | 株式会社日立製作所 | Distribution system state estimation device, method and program |
| JP4531638B2 (en) * | 2005-06-15 | 2010-08-25 | 中国電力株式会社 | Transformer load assumption method, transformer load assumption device |
| JP2009207302A (en) * | 2008-02-28 | 2009-09-10 | Mitsubishi Electric Corp | Backward flow estimation method and backward flow estimation system of distributed power supply in distribution line |
| JP5355147B2 (en) * | 2009-02-27 | 2013-11-27 | 株式会社東芝 | Emission factor calculator and emission factor calculation method |
| JP5711623B2 (en) * | 2010-07-22 | 2015-05-07 | 中部電力株式会社 | Transformer management apparatus, method and program thereof |
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