JP2009069065A - Device for measuring effective leakage current - Google Patents
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本発明は、例えば電源ラインの絶縁点検に使用される有効漏れ電流測定器に関し、詳しくは、三相３線式の配電系統において測定器の誤結線を検出可能とした有効漏れ電流測定器に関するものである。 The present invention relates to an effective leakage current measuring device used for, for example, power supply line insulation inspection, and more particularly to an effective leakage current measuring device capable of detecting an erroneous connection of a measuring device in a three-phase three-wire distribution system. It is.
配電系統の基本波実効値、基本波位相角、漏れ電流、高調波等を測定して配電系統の品質を解析、評価する電源ラインモニタは、例えば特許文献１に記載されている。
図５は、三相３線式の配電系統を対象として、特許文献１に記載された電源ラインモニタを有効漏れ電流測定器１０Ａとして使用した場合のブロック図である。
A power supply line monitor that analyzes and evaluates the quality of a power distribution system by measuring the fundamental wave effective value, fundamental wave phase angle, leakage current, harmonics, and the like of the power distribution system is described in
FIG. 5 is a block diagram when the power supply line monitor described in
図５において、ａ，ｂ，ｃは三相３線式の電路、Ｒａ，Ｒｃは電路ａ，ｃの対地抵抗、Ｃａ，Ｃｃは電路ａ，ｃの対地静電容量、１１は、二つの電路間の線間電圧（例えば、電路ａとＢ種接地による接地電路ｂとの間の線間電圧Ｖａｂ）が有効漏れ電流測定時の基準電圧（取得電圧ともいう）として入力されると共に、入力電圧値のレベル調整等を行う電圧入力部、ＺＣＴは接地電路ｂに接続されて合成漏れ電流（有効漏れ電流、無効漏れ電流のベクトル和）Ｉｇを検出する零相変流器、１２は合成漏れ電流Ｉｇが入力されてそのレベル調整等を行う漏れ電流入力部、２ａ，２ｂはＡ／Ｄ変換回路、３は有効漏れ電流等を演算する演算部（ＣＰＵ）、４はＡ／Ｄ変換回路２ａ，２ｂを介して収集された演算部３の入力データや演算結果を格納するメモリ、５はｓｉｎ波、ｃｏｓ波の基準波形データが記憶された基準波形データメモリ、６は演算部３による演算結果を表示し、または外部へ伝送するための出力部である。
ここで、上記基準波形データは、電圧入力部１１への入力電圧波形と同一周期であり、Ａ／Ｄ変換回路２ａ，２ｂと同じ分解能でテーブル上に予め作成されたデータである。
In FIG. 5, a, b, and c are three-phase three-wire electric circuits, R a and R c are ground resistances of the electric circuits a and c, C a and C c are ground capacitances of the electric circuits a and c, and 11 is The line voltage between the two electric circuits (for example, the line voltage V ab between the electric circuit a and the ground electric circuit b by the B type grounding) is input as a reference voltage (also referred to as an acquired voltage) at the time of measuring effective leakage current. Rutotomoni, voltage input unit for adjusting the level of the input voltage value, ZCT synthetic leakage current is connected to a ground path b (effective leakage current, the vector sum of the invalid leakage current) zero-phase detecting an I g current transformer , 12 is a leakage current input unit that receives the combined leakage current Ig and adjusts the level thereof, 2a and 2b are A / D conversion circuits, 3 is a calculation unit (CPU) that calculates an effective leakage current, etc. Input data and calculation results of the
Here, the reference waveform data has the same period as the input voltage waveform to the voltage input unit 11, and is data created in advance on the table with the same resolution as the A / D conversion circuits 2a and 2b.
次に、図６は、図５の構成により有効漏れ電流Ｉｇｒを求めるための原理を示すベクトル図である。なお、有効漏れ電流Ｉｇｒは図５における対地抵抗Ｒａ，Ｒｃにそれぞれ流れる漏れ電流Ｉｇｒａ，Ｉｇｒｃのベクトル和であるが、電路ａ，ｃの絶縁不良が同時に起こることは稀であるため、対地抵抗Ｒａ，Ｒｃによる有効漏れ電流Ｉｇｒは、対地抵抗Ｒａ，Ｒｃのうち何れか一方による漏れ電流値、つまり、Ｉｇｒ＝Ｉｇｒａ、またはＩｇｒ＝Ｉｇｒｃと考えて良い。なお、ＩｇｒａはＶａｂと同相、ＩｇｒｃはＶｃｂと同相である。
この図６を参照しながら、従来技術による有効漏れ電流Ｉｇｒの測定方法を以下に略述する。
Next, FIG. 6 is a vector diagram showing the principle for obtaining the effective leakage current I gr with the configuration of FIG. The effective leakage current I gr is a vector sum of the leakage currents I gra and I grc flowing in the ground resistances R a and R c in FIG. 5 respectively, but it is rare that an insulation failure of the electric paths a and c occurs at the same time. Therefore, ground resistance R a, the effective leakage current I gr by R c are ground resistance R a, the leakage current due to either of R c, that is, I gr = I gra or I gr = I grc and thinking, Good. Note that I gra is in phase with V ab and I grc is in phase with V cb .
A method for measuring the effective leakage current I gr according to the prior art will be briefly described below with reference to FIG.
いま、取得電圧がＶａｂであるとすると、まず、図５の演算部３は、電圧入力部１１から取り込んだ所定波数分の電圧Ｖａｂと基準波形データメモリ５内のｓｉｎ波データ、ｃｏｓ波データとを用いて積和演算を行い、電圧Ｖａｂの第１積算値、第２積算値を求める。同様に、演算部３は、漏れ電流入力部１２から取り込んだ所定波数分の合成漏れ電流Ｉｇと前記ｓｉｎ波データ、ｃｏｓ波データとを用いて積和演算を行い、合成漏れ電流Ｉｇの第１積算値、第２積算値を求める。
ここで、上記各積算値の演算方法は本発明の要旨ではないため、説明を省略する。
Now, assuming that the acquired voltage is V ab , the
Here, since the calculation method of each integrated value is not the gist of the present invention, the description thereof is omitted.
次に、これらの電圧Ｖａｂ及び合成漏れ電流Ｉｇの第１積算値、第２積算値を用いて、図６に示すように、基準波形に対する電圧Ｖａｂ及び合成漏れ電流Ｉｇの位相角θ１，θ２をそれぞれ求める。次いで、合成漏れ電流Ｉｇの第１積算値、第２積算値並びに位相角θ２を用いて、合成漏れ電流Ｉｇの基本波成分Ｉｇ(1)を求める。
なお、有効漏れ電流Ｉｇｒだけでなく、更に絶縁抵抗も求める場合には、上記に加えて、電圧Ｖａｂの第１積算値、第２積算値並びに位相角θ１を用いて、電圧Ｖａｂの基本波成分Ｖａｂ(1)を求める。
Next, a first integrated value of these voltages V ab and synthetic leakage current I g, by using the second integrated value, as shown in FIG. 6, the phase angle of the voltage V ab and synthetic leakage current I g to the reference waveform θ 1 and θ 2 are obtained, respectively. Then, the first integrated value of the combined leakage current I g, the second integrated value and by using the phase angle theta 2, determine the fundamental component I g of synthetic leakage current I g (1).
When not only the effective leakage current I gr but also the insulation resistance is obtained, in addition to the above, the voltage V ab is calculated using the first integrated value, the second integrated value, and the phase angle θ 1 of the voltage V ab. The fundamental wave component V ab (1) is obtained.
更に、θ１とθ２との位相差、すなわち電圧Ｖａｂに対する合成漏れ電流Ｉｇの位相角θを求める。
いま、対地静電容量Ｃａ，Ｃｃによる漏れ電流Ｉｇｃａ，Ｉｇｃｃが等しいとすると、そのベクトル合成値である無効漏れ電流Ｉｇｃは図６に示す如くＶｃａと同相であり、他方、対地抵抗Ｒａ，Ｒｃによる有効漏れ電流Ｉｇｒは、前述のようにＩｇｒ＝ＩｇｒａまたはＩｇｒ＝Ｉｇｒｃである。
Further, the phase difference between the theta 1 and theta 2, i.e. obtains the phase angle theta synthetic leakage current I g for the voltage V ab.
If the leakage currents I gca and I gcc due to the ground capacitances C a and C c are equal, the reactive leakage current I gc, which is a vector composite value thereof, is in phase with V ca as shown in FIG. The effective leakage current I gr due to the ground resistances R a and R c is I gr = I gra or I gr = I grc as described above.
従って、図６において、Ｉｇｒａ，Ｉｇｒｃ，Ｉｇｃの位相差が６０°であることを考慮すると、有効漏れ電流Ｉｇｒは、数式１によって求めることができる。
［数式１］
Ｉｇｒ＝Ｉｇ(1)ｃｏｓθ＋Ｉｇ(1)ｓｉｎθ／ｔａｎ６０°
＝（２／√３）×Ｉｇ(1)×ｓｉｎ（θ＋６０°）
図５の演算部３は、上記数式１の演算により有効漏れ電流Ｉｇｒを求め、その測定値を合成漏れ電流Ｉｇや位相角θと共に出力部６に数値表示すると共に、必要に応じて出力部６から外部に伝送することとなる。
Therefore, in FIG. 6, considering that the phase difference of I gra , I grc , and I gc is 60 °, the effective leakage current I gr can be obtained by
[Formula 1]
I gr = I g (1) cos θ + I g (1) sin θ / tan 60 °
= (2 / √3) × I g (1) × sin (θ + 60 °)
The
上記のように、従来技術によれば、有効漏れ電流Ｉｇｒを合成漏れ電流Ｉｇの基本波成分Ｉｇ(1)と位相角θとから求めることができる。
しかし、電路ａ，ｂ，ｃに対する電圧入力部１１の結線を間違えると、電圧Ｖａｂに対する合成漏れ電流Ｉｇの位相角θを求めたつもりであっても、他の線間電圧（例えばＶｃｂ）に対する合成漏れ電流Ｉｇの位相角を求めてしまい、その結果、前記数式１により演算した有効漏れ電流Ｉｇｒの値が実際の値とは大きく異なってしまうという問題があった。
ここで、上記の誤結線には、接続するべき電路ａ，ｂを電路ｃ，ｂと間違える（すなわちＶａｂとＶｃｂとを間違える）ような場合以外に、電路ａ，ｂを逆に接続して極性を間違える（ＶａｂとＶｂａとを間違える）場合も含まれる。
また、零相変流器ＺＣＴの向きを間違える場合も含まれる。
As described above, according to the prior art, it can be obtained from the a phase angle θ the effective leakage current I gr synthetic leakage current I g of the fundamental wave component I g (1).
However, paths a, b, the wrong connection of the voltage input section 11 with respect to c, even going calculated phase angle θ of the composite leakage current I g for the voltage V ab, other line voltage (e.g., V cb ) it will seek the phase angle of the composite leakage current I g for, as a result, the the value of the actual value of the effective leakage current I gr computed by
Here, except for the case where the electric circuits a and b to be connected are mistaken for the electric circuits c and b (that is, V ab and V cb are mistaken), the electric circuits a and b are connected in reverse to the erroneous connection. In this case, the polarity is wrong ( Vab and Vba are wrong).
Moreover, the case where the direction of the zero phase current transformer ZCT is wrong is also included.
なお、単相３線式、三相４線式の配電系統では、上述の如く誤結線しても特に支障はないが、誤結線によって有効漏れ電流Ｉｇｒの値が大きく異なる三相３線式の配電系統では、有効漏れ電流Ｉｇｒの演算に先立って誤結線を高精度に判定できることが望まれていた。 In the single-phase three-wire and three-phase four-wire distribution systems, there is no particular problem even if the connection is incorrect as described above. However, the effective leakage current I gr differs greatly depending on the connection. In this distribution system, it has been desired that an erroneous connection can be determined with high accuracy prior to the calculation of the effective leakage current I gr .
一方、三相電力測定装置において、装置の誤結線を検出可能とした従来技術は、例えば特開２０００−３３８１４７号公報「電力測定装置」や特開２００１−１２４８０６号公報「三相電力測定器および三相電力量計ならびにその結線状態判別方法」等が知られているが、有効漏れ電流測定器の一機能として事前に誤結線を判定可能としたものは未だ提供されていない。 On the other hand, in the three-phase power measuring apparatus, conventional techniques that enable detection of erroneous connection of the apparatus include, for example, Japanese Patent Laid-Open No. 2000-338147 “Power Measuring Device” and Japanese Patent Laid-Open No. 2001-124806 “Three-Phase Power Measuring Device and A “three-phase watt-hour meter and its connection state determination method” and the like are known, but no function capable of determining an erroneous connection in advance as a function of an effective leakage current measuring device has been provided yet.
そこで本発明の解決課題は、三相３線式の配電系統を対象として有効漏れ電流を測定する際に、誤結線を高精度かつ容易に検出可能とした有効漏れ電流測定器を提供することにある。 Therefore, the problem to be solved by the present invention is to provide an effective leakage current measuring device capable of easily and accurately detecting misconnection when measuring effective leakage current for a three-phase three-wire distribution system. is there.
上記課題を解決するため、請求項１に係る発明は、三相３線式の配電系統と接地点との間を流れる合成漏れ電流を検出する手段と、
配電系統の線間電圧を検出する手段と、
前記線間電圧と前記合成漏れ電流との間の位相角、及び、前記合成漏れ電流を用いて、配電系統の対地抵抗を介した有効漏れ電流を演算する手段と、
を備えた有効漏れ電流測定器において、
ある線間電圧を取得電圧として前記測定器に入力した際に、その取得電圧と前記合成漏れ電流との間の位相角が、前記取得電圧に対応する所定の角度範囲内に存在しないことを検出して前記測定器の配電系統に対する誤結線を判定する判定手段を備えたものである。
In order to solve the above-mentioned problem, the invention according to claim 1 detects a combined leakage current flowing between a three-phase three-wire distribution system and a grounding point,
Means for detecting the line voltage of the distribution system;
A phase angle between the line voltage and the combined leakage current, and a means for calculating an effective leakage current through a ground resistance of a distribution system using the combined leakage current;
In the effective leakage current measuring instrument with
When a certain line voltage is input to the measuring instrument as an acquired voltage, it is detected that the phase angle between the acquired voltage and the combined leakage current does not exist within a predetermined angle range corresponding to the acquired voltage And determining means for determining an erroneous connection of the measuring device to the power distribution system.
前記所定の角度範囲としては、請求項２に記載するように１２０°の幅を持たせるか、誤結線の判定精度を一層高めるために、請求項３に記載する如く６０°の幅を持たせることが望ましい。
The predetermined angle range has a width of 120 ° as described in
更に、請求項４に記載する如く、判定手段による判定動作は、少なくとも二つの線間電圧を取得電圧として、各取得電圧及び合成漏れ電流について誤結線の判定動作を実行しても良い。 Further, according to a fourth aspect of the present invention, the determination operation by the determination means may be performed with a determination of erroneous connection for each acquired voltage and combined leakage current using at least two line voltages as the acquired voltages.
請求項１，２または４に係る発明によれば、取得電圧に応じて決まる所定の角度範囲内に合成漏れ電流の位相角が存在しない場合に、配電系統の電路に対して測定器（電圧入力部または合成漏れ電流検出手段）が誤結線されていると判定することができる。この場合の判定ロジックは比較的単純で済むから、既存の有効漏れ電流測定器のソフトウェアに若干の変更を加えるだけで容易に実現可能であり、コスト高になるおそれもない。
また、請求項３に係る発明によれば、誤結線を一層高精度に判定することが可能になる。
According to the first, second, or fourth aspect of the invention, when the phase angle of the combined leakage current does not exist within a predetermined angle range determined according to the acquired voltage, the measuring device (voltage input) Or the combined leakage current detection means) can be determined to be misconnected. Since the determination logic in this case is relatively simple, the determination logic can be easily realized by making a slight change to the software of the existing effective leakage current measuring instrument, and there is no risk of increasing the cost.
Moreover, according to the invention which concerns on
以下、図に沿って本発明の実施形態を説明する。
図１は、実施形態に係る有効漏れ電流測定器１０の構成を示すブロック図であり、図５と同一の構成要素には同一の番号を付してある。
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of an effective leakage current measuring
図１において、前記同様に、ａ，ｂ，ｃは三相３線式の電路、Ｒａ，Ｒｃは電路ａ，ｃの対地抵抗、Ｃａ，Ｃｃは電路ａ，ｃの対地静電容量、１１は二つの電路間の線間電圧が取得電圧として入力され、そのレベル調整等を行う電圧入力部、ＺＣＴはＢ種接地の接地電路ｂに接続されて漏れ電流Ｉｇを検出する零相変流器、１２は漏れ電流Ｉｇのレベル調整等を行う漏れ電流入力部、２ａ，２ｂは各入力部１１，１２にそれぞれ接続されたＡ／Ｄ変換回路である。
また、ＣＰＵ等からなる演算部３は、従来技術と同様に、メモリ４に格納されたデータ（Ａ／Ｄ変換回路２ａ，２ｂの出力データ）及び基準波形データメモリ５内の基準波形データ等を用いて、有効漏れ電流Ｉｇｒを演算する。
In FIG. 1, a, b, and c are three-phase three-wire electric circuits, R a and R c are ground resistances of the electric circuits a and c, and C a and C c are ground electrostatics of the electric circuits a and c. capacity, 11 line voltage between the two paths is input as acquired voltage, the voltage input section for performing the level adjustment, ZCT detects the leakage current I g is connected to a ground path b of B type grounding zero A phase current transformer, 12 is a leakage current input unit for adjusting the level of leakage current Ig , and the like, and 2a and 2b are A / D conversion circuits connected to the
Further, the
本実施形態では、上記演算部３の出力側に判定部７が設けられており、この判定部７は、電路ａ，ｂ，ｃに対する電圧入力部１１の誤結線を検出する機能を備えている。
この誤結線検出機能は、以下の通りである。
In this embodiment, the
This erroneous connection detection function is as follows.
例えば、取得電圧をＶａｂとするために、取得電圧がＶａｂの場合を正しい結線と見なすように有効漏れ電流測定器１０に予め設定しておく。電圧入力部１１が電路ａ，ｂに正しく接続されている場合（正常結線時）、演算部３により検出される電圧Ｖａｂと漏れ電流Ｉｇとの間の位相角θは、図２に示すように取得電圧Ｖａｂの位相角を基準（＝０°）とした０°〜１２０°の範囲にある。この理由を以下に説明する。
For example, in order to obtain voltage and V ab, acquiring voltage preliminarily set to enable leakage
すなわち、電路ａだけが絶縁劣化している場合、無効漏れ電流Ｉｇｃを無視すれば、Ｉｇ＝Ｉｇｒａ（＝Ｉｇｒ）、つまりＩｇはＶａｂと同相になり、θ＝０°となる。また、電路ｃだけが絶縁劣化している場合、無効漏れ電流Ｉｇｃを無視すれば、Ｉｇ＝Ｉｇｒｃ（＝Ｉｇｒ）、つまりＩｇはＶｃｂと同相になり、θ＝６０°となる。ここで、無効漏れ電流Ｉｇｃを考慮したとしても、Ｉｇは常に０°以上の位相角θをもって存在する。
一方、電路ａ，ｂに絶縁劣化がない理想的な状態では、Ｉｇ＝Ｉｇｃとなって無効漏れ電流Ｉｇｃのみとなり、ＩｇはＶｃａと同相になるため、θ＝１２０°となる。
That is, when only the electric circuit a is deteriorated in insulation, if the reactive leakage current I gc is ignored, I g = I gra (= I gr ), that is, I g is in phase with V ab and θ = 0 ° Become. Further, when only the electric circuit c is deteriorated in insulation, if the reactive leakage current I gc is ignored, I g = I grc (= I gr ), that is, I g is in phase with V cb and θ = 60 ° Become. Here, even considering invalid leakage current I gc, I g is always present with a phase angle θ of more than 0 °.
On the other hand, in an ideal state where there is no insulation deterioration in the electric paths a and b, I g = I gc and only the reactive leakage current I gc is obtained, and I g is in phase with V ca , so θ = 120 °. .
従って、電圧入力部１１が電路ａ，ｂに正しく接続されており、電圧入力部１１における取得電圧がＶａｂである場合には、上述の如くθの存在する範囲は０°〜１２０°である。同様にして、取得電圧がＶｂｃである場合のθの存在する範囲は、Ｖａｂの位相角を基準（＝０°）とすれば１２０°〜２４０°、同じく取得電圧がＶｃａの場合は２４０°〜３６０°（０°）、取得電圧がＶｃｂの場合は３００°〜６０°、取得電圧がＶａｃの場合は６０°〜１８０°、取得電圧がＶｂａの場合は１８０°〜３００°となる。 Therefore, when the voltage input unit 11 is correctly connected to the electric paths a and b and the acquired voltage at the voltage input unit 11 is V ab , the range where θ exists is 0 ° to 120 ° as described above. . Similarly, the range where θ exists when the acquired voltage is V bc is 120 ° to 240 ° when the phase angle of V ab is set as a reference (= 0 °), and when the acquired voltage is V ca 240 ° to 360 ° (0 °), 300 ° to 60 ° when the acquisition voltage is V cb , 60 ° to 180 ° when the acquisition voltage is V ac , 180 ° to 300 when the acquisition voltage is V ba °.
よって、判定部７は、位相角θが取得電圧、例えばＶａｂに応じた範囲０°〜１２０°に存在しないことを検出した場合に、電圧入力部１１が本来接続されるべき電路ａ，ｂに接続されていないか、または、零相変流器ＺＣＴを接続する向きが間違っていると判断し、電圧入力部１１または零相変流器ＺＣＴ（どちらかの特定はできない）の誤結線を判定する。こうして誤結線と判定した場合には、判定部７から出力部８に信号を送り、音声や表示器による警報出力（「結線が間違っているため確認して下さい。」等）を行って測定者に知らせればよい。
Therefore, when the
ここで、図３は、正常結線時にθが存在する範囲を、取得電圧の位相角を基準（０°）として取得電圧ごとに示した模式図であり、例えば、取得電圧がＶａｂの時にはＶａｂの位相角を０°とした０°〜１２０°、取得電圧がＶｃａの時にはＶｃａの位相角を０°とした２４０°〜３６０°（０°）が、それぞれの正常結線時におけるθの存在範囲であることを意味している。なお、図３を一覧表にして示すと、図４の通りである。
図３に示すように、θが時計方向に減少すると有効漏れ電流Ｉｇｒが支配的になり、θが反時計方向に増加すると無効漏れ電流Ｉｇｃが支配的になることがわかる。
Here, FIG. 3 is a schematic diagram showing the range in which θ exists during normal connection for each acquired voltage with the phase angle of the acquired voltage as a reference (0 °). For example, when the acquired voltage is
As shown in FIG. 3, it can be seen that the effective leakage current I gr becomes dominant when θ decreases in the clockwise direction, and the reactive leakage current I gc becomes dominant when θ increases in the counterclockwise direction.
以上のように、この実施形態によれば、位相角θに着目することで測定器の誤結線状態を判定可能である。
ここで、上記実施形態では、請求項２に記載したように、取得電圧と合成漏れ電流との間の位相角θが、１２０°の幅を持つ範囲内にあるか否かによって誤結線を判定している。
しかし、結線が正常であっても、対地静電容量Ｃａ，Ｃｃのアンバランス等に起因して上記位相角θが１２０°を超えることもあるので、結線が正常であると判断すべき角度範囲を、１２０°より広い幅で設定しておいても良い。
As described above, according to this embodiment, it is possible to determine the erroneous connection state of the measuring device by paying attention to the phase angle θ.
Here, in the above embodiment, as described in
However, even if the connection is normal, the phase angle θ may exceed 120 ° due to the unbalance of the capacitances C a and C c to the ground, so it should be determined that the connection is normal. The angle range may be set with a width wider than 120 °.
更に、電路に絶縁劣化がない理想的な状態では、漏れ電流Ｉｇのうち無効漏れ電流Ｉｇｃが支配的になるので、位相角θは、取得電圧に応じて存在し得る範囲の最大値に近くなり、例えば取得電圧がＶａｂの場合にはθが１２０°近くになる。
従って、判定部７における判定の角度範囲を更に狭め、取得電圧の位相角を基準として例えば６０°〜１２０°の範囲とし、θがこの範囲以外の値である場合を誤結線と判定することにより、絶縁劣化がない状態における誤結線の判定精度を高めることができる。
つまり、請求項３に記載したように、判定の角度範囲の幅を６０°として誤結線を判定することも有効である。
Further, in an ideal state where there is no insulation deterioration in path, so disable leakage current I gc of the leakage current I g is dominant, the phase angle theta, the maximum value of the range that can be present according to the acquired voltage For example, when the acquired voltage is V ab , θ is close to 120 °.
Accordingly, the determination angle range in the
That is, as described in
このようにすれば、取得電圧がＶａｂの時の正常結線時の角度範囲が６０°〜１２０°、Ｖｂｃの時の範囲が１８０°〜２４０°、Ｖｃａの時の範囲が３００°〜３６０°（０°）、Ｖｃｂの時の範囲が０°〜６０°、Ｖａｃの時の範囲が１２０°〜１８０°、Ｖｂａの時の範囲が２４０°〜３００°となり、６つの取得電圧について正常結線時の角度範囲が重複せず、０°〜３６０°を６等分した状態に設定することができる。これにより、それぞれの取得電圧について、θが該当する範囲内に存在しない場合には誤結線と判定する判定精度を一層高めることができる。 In this way, the angle range during normal connection when the acquired voltage is V ab is 60 ° to 120 °, the range when V bc is 180 ° to 240 °, and the range when V ca is 300 ° to 360 ° (0 °), the range when V cb is 0 ° to 60 °, the range when V ac is 120 ° to 180 °, the range when V ba is 240 ° to 300 °, 6 acquisitions With respect to the voltage, the angle ranges at the time of normal connection do not overlap, and it is possible to set a state in which 0 ° to 360 ° is divided into six equal parts. Thereby, it is possible to further improve the determination accuracy for determining the erroneous connection when θ does not exist within the corresponding range for each acquired voltage.
なお、図３，図４に示したように、取得電圧に応じた所定の角度範囲内にθが存在したとしても、結線が正常であるとは必ずしも断定できない。例えば、取得電圧をＶａｂとして検出したθが０°〜１２０°の範囲内にある時、図３，図４によれば、この範囲は取得電圧がＶｃｂまたはＶａｃである時にθが存在する角度範囲と一部重なっているので、正常結線の場合（電路ａ，ｂに接続）と、誤結線の場合（電路ｃ，ｂに誤接続、または電路ａ，ｃに誤接続）とがあり得ることになる。
すなわち、θが０°〜１２０°の範囲内に存在したとしても、電圧入力部１１が電路ｃ，ｂまたは電路ａ，ｃに誤結線されている可能性も否定できない。
As shown in FIGS. 3 and 4, even if θ exists within a predetermined angle range corresponding to the acquired voltage, it cannot be determined that the connection is normal. For example, when the acquired voltage is V ab and θ is in the range of 0 ° to 120 °, according to FIGS. 3 and 4, this range exists when the acquired voltage is V cb or V ac. There is a case of normal connection (connected to electric circuits a and b) and a case of incorrect connection (incorrect connection to electric circuits c and b, or incorrect connection to electric circuits a and c). Will get.
That is, even if θ is in the range of 0 ° to 120 °, the possibility that the voltage input unit 11 is erroneously connected to the electric circuits c and b or the electric circuits a and c cannot be denied.
そこで、誤結線の検出精度を向上させるには、二つの取得電圧、例えばＶａｂ，Ｖｃｂについて、上述した判定動作をそれぞれ行えば良い。つまり、１回目の判定動作として、取得電圧Ｖａｂに対してθが０°〜１２０°の範囲内に存在するか否かを判定し、存在する場合には、更に２回目の判定動作として、取得電圧Ｖｃｂに対してθが３００°〜６０°の範囲内に存在するか否かを判定する。 Therefore, in order to improve the detection accuracy of erroneous connection, the above-described determination operation may be performed for two acquired voltages, for example, V ab and V cb . That is, as the first determination operation, it is determined whether or not θ is within a range of 0 ° to 120 ° with respect to the acquired voltage V ab . It is determined whether or not θ is within a range of 300 ° to 60 ° with respect to the acquired voltage V cb .
２回目の判定動作の結果、取得電圧Ｖｃｂに対してθが３００°〜６０°の範囲内に存在すれば、結果的にθは０°〜６０°の範囲内に存在することになる。従って、第１回目の判定動作時に取得電圧がＶａｃであった可能性（電路ａ，ｃに誤接続していた可能性）はなくなる。
また、２回目の判定動作の結果、取得電圧Ｖｃｂに対してθが３００°〜６０°の範囲内に存在しない場合には、θは６０°〜１２０°の範囲内に存在することになる。従って、第１回目の判定動作時に取得電圧がＶｃｂであった可能性（電路ｃ，ｂに誤接続していた可能性）はなくなる。
As a result of the second determination operation, if θ is in the range of 300 ° to 60 ° with respect to the acquired voltage V cb , as a result, θ is in the range of 0 ° to 60 °. Therefore, there is no possibility that the acquired voltage was Vac during the first determination operation (possibility of erroneous connection to the electric paths a and c).
When θ is not in the range of 300 ° to 60 ° with respect to the acquired voltage V cb as a result of the second determination operation, θ is in the range of 60 ° to 120 °. . Therefore, there is no possibility that the acquired voltage was V cb during the first determination operation (possibility of erroneous connection to the electric circuits c and b).
このように、誤結線を判定する角度範囲が、取得電圧の位相角を基準とした所定の角度範囲である場合にも、複数の取得電圧に対して判定動作を繰り返し行うことにより誤結線の判定精度を高めることができる。 As described above, even when the angle range for determining the erroneous connection is a predetermined angle range based on the phase angle of the acquired voltage, the determination of the erroneous connection is performed by repeatedly performing the determination operation on a plurality of acquired voltages. Accuracy can be increased.
次に、請求項４に係る発明の実施形態として、電圧入力部１１の誤結線か、または、合成漏れ電流検出手段としての零相変流器ＺＣＴの誤結線（接続する向きの間違い）かを特定する方法について説明する。
仮に取得電圧がＶａｂ，Ｖｃｂである場合、取得電圧Ｖａｂに対してＶｃｂが６０°±１０°の範囲内に存在するか否かを判定し、存在する場合には、その時の電圧入力部１１の結線は正常であると判断する。Ｖｃｂが６０°±１０°の範囲内に存在しない場合には、その時の電圧入力部１１の結線は誤結線であると判断する。
結線が正常であると判断された場合、二つの取得電圧のうちの一方（例えばＶａｂ）と合成漏れ電流Ｉｇとの間の位相角θが０°〜１２０°の範囲内に存在するか否かを判定し、存在しなければ、零相変流器ＺＣＴの誤結線であることがわかる。
Next, as an embodiment of the invention according to
If the acquired voltages are V ab and V cb, it is determined whether or not V cb is within a range of 60 ° ± 10 ° with respect to the acquired voltage V ab . It is determined that the connection of the input unit 11 is normal. When V cb does not exist within the range of 60 ° ± 10 °, it is determined that the connection of the voltage input unit 11 at that time is an incorrect connection.
If the connection is determined to be normal, or present in the range phase angle θ is 0 ° to 120 ° between one (e.g. V ab) Synthesis leakage current I g of the two acquired voltage If it does not exist, it is found that the zero-phase current transformer ZCT is an erroneous connection.
１０：有効漏れ電流測定器
１１：電圧入力部
１２：漏れ電流入力部
２ａ，２ｂ：Ａ／Ｄ変換回路
３：演算部
４：メモリ
５：基準波形データメモリ
７：判定部
８：出力部
ＺＣＴ：零相変流器
10: Effective leakage current measuring instrument 11: Voltage input unit 12: Leakage current input unit 2a, 2b: A / D conversion circuit 3: Calculation unit 4: Memory 5: Reference waveform data memory 7: Determination unit 8: Output unit ZCT: Zero phase current transformer
Claims (4)
前記配電系統の線間電圧を検出する手段と、
前記線間電圧と前記合成漏れ電流との間の位相角、及び、前記合成漏れ電流を用いて、前記配電系統の対地抵抗を介した有効漏れ電流を演算する手段と、
を備えた有効漏れ電流測定器において、
ある線間電圧を取得電圧として前記測定器に入力した際に、その取得電圧と前記合成漏れ電流との間の位相角が、前記取得電圧に対応する所定の角度範囲内に存在しないことを検出して前記測定器の前記配電系統に対する誤結線を判定する判定手段を備えたことを特徴とする有効漏れ電流測定器。 Means for detecting a combined leakage current flowing between a three-phase three-wire distribution system and a ground point;
Means for detecting a line voltage of the distribution system;
A phase angle between the line voltage and the combined leakage current, and a means for calculating an effective leakage current through a ground resistance of the distribution system using the combined leakage current;
In the effective leakage current measuring instrument with
When a certain line voltage is input to the measuring instrument as an acquired voltage, it is detected that the phase angle between the acquired voltage and the combined leakage current does not exist within a predetermined angle range corresponding to the acquired voltage And an effective leakage current measuring device comprising a determining means for determining an erroneous connection of the measuring device to the power distribution system.
前記所定の角度範囲が、１２０°の幅を持つことを特徴とする有効漏れ電流測定器。 The effective leakage current measuring instrument according to claim 1,
An effective leakage current measuring instrument characterized in that the predetermined angle range has a width of 120 °.
前記所定の角度範囲が、６０°の幅を持つことを特徴とする有効漏れ電流測定器。 The effective leakage current measuring instrument according to claim 1,
An effective leakage current measuring instrument characterized in that the predetermined angle range has a width of 60 °.
少なくとも二つの線間電圧を前記取得電圧として、前記判定手段が、各取得電圧及び合成漏れ電流に対して誤結線の判定動作を実行することを特徴とする有効漏れ電流測定器。 In the effective leakage current measuring device according to any one of claims 1 to 3,
The effective leakage current measuring device, wherein the determination means executes an operation of determining an erroneous connection for each acquired voltage and the combined leakage current, using at least two line voltages as the acquired voltage.
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