JP7051955B2

JP7051955B2 - Generator internal failure detection method, generator internal failure detection device

Info

Publication number: JP7051955B2
Application number: JP2020144511A
Authority: JP
Inventors: 弘人黒田; 綾太久原
Original assignee: 西芝電機株式会社
Priority date: 2020-08-28
Filing date: 2020-08-28
Publication date: 2022-04-11
Anticipated expiration: 2040-08-28
Also published as: JP2022039470A

Description

本発明は、発電機内部故障検出方法、発電機内部故障検出装置に関するものである。 The present invention relates to a generator internal failure detection method and a generator internal failure detection device.

発電機を運転する際には各種の規格や規則により発電機の内部故障を検出することが求められる。例えば、ロンドンに本部を置く、ロイド船級協会（Lloyd's Register of shipping）により定められた船級規格上のパート６チャプター２のセクション６に記述されている内容によると、１，５００ｋＶＡ以上の高圧の発電機には、発電機内部回路が短絡した場合に発電機の焼損や発電機漏電事故等を防ぐことを目的とした保護装置を設ける必要があると記されている。 When operating a generator, it is required to detect the internal failure of the generator according to various standards and regulations. For example, according to the content described in Section 6 of Part 6 Chapter 2 on the ship classification standard set by the Lloyd's Register of shipping, which is headquartered in London, a generator with a high voltage of 1,500 kVA or more. It is stated that it is necessary to provide a protective device for the purpose of preventing the generator from burning or a generator leakage accident when the generator internal circuit is short-circuited.

現在、発電機に設けられる保護装置としては比率差動継電器が使用されている。比率差動継電器とは、主に発電機やトランス等に使用される保護継電器の一種であり、発電機やトランスの異相間短絡や地絡をいち早く検出することで発電機内部故障時に、短絡電流や地絡電流が流れ続けることにより過熱し、火災等の事故に発展することを防止することを目的として使用されている。 Currently, a ratio differential relay is used as a protective device provided in a generator. A ratio differential relay is a type of protective relay mainly used for generators and transformers. By quickly detecting short-circuits between different phases and ground faults in generators and transformers, short-circuit current occurs when an internal generator fails. It is used for the purpose of preventing overheating due to continuous flow of ground fault current and development of accidents such as fire.

比率差動継電器の検出原理は、図２に示すように、発電機内部巻線８０の中性点と各相の外部接点部分にそれぞれ変流器ＣＴ１，ＣＴ２を設置し、その変流器ＣＴ１，ＣＴ２から得られる発電機内部巻線８０への流入電流Ｉ１と発電機内部巻線８０から発電機外部へ出ていく流出電流Ｉ２の差電流（Ｉ２－Ｉ１）とを比較し、異相間短絡Ｓ１を起こした際などに流入電流Ｉ１と差電流（Ｉ２－Ｉ１）の比が一定比率を超えた場合に発電機内部故障とみなしている。 As shown in FIG. 2, the detection principle of the ratio differential relay is that the current transformers CT1 and CT2 are installed at the neutral point of the generator internal winding 80 and the external contact portion of each phase, respectively, and the current transformer CT1 , The difference current (I2-I1) of the inflow current I1 to the generator internal winding 80 obtained from CT2 and the outflow current I2 going out from the generator internal winding 80 to the outside of the generator is compared, and a short circuit between different phases is performed. When the ratio of the inflow current I1 and the difference current (I2-I1) exceeds a certain ratio when S1 is caused, it is regarded as a generator internal failure.

しかし、同相間短絡Ｓ２については、流入電流Ｉ１と流出電流Ｉ２の値が変化しないため、比率差動継電器では故障を検出することができない。また、比率差動継電器の場合、流入電流を検出する変流器が故障検出の対象である発電機に搭載されることがあり、発電機が、その駆動機である原動機の振動を受ける。この場合、原動機の振動によって変流器が破損してしまい、発電機の故障を検出することができなくなるおそれがあった。 However, with respect to the in-phase short circuit S2, since the values of the inflow current I1 and the outflow current I2 do not change, a failure cannot be detected by the ratio differential relay. Further, in the case of a ratio differential relay, a current transformer that detects an inflow current may be mounted on a generator that is a target of failure detection, and the generator receives vibration of a prime mover that is a driving device thereof. In this case, the current transformer may be damaged by the vibration of the prime mover, and it may not be possible to detect the failure of the generator.

上述した比率差動継電器以外の発電機内部故障検出方法として、発電機が短絡故障を起こした際の発電機内部巻線インピーダンスの値の変化を検出する方法が考えられる。通電時の発電機内部巻線のインピーダンスの変化をとらえる必要があるが、ここで通電状態回路内の導電体や電力系統のインピーダンス値を監視、計測する方法として、次数間高調波を使用して計測する方法が知られている。例えば次数間高調波を使用しインピーダンスの変化を監視したものとして以下（従来例１～３）のようなものがある。 As a method for detecting an internal failure of a generator other than the above-mentioned ratio differential relay, a method of detecting a change in the value of the internal winding impedance of the generator when the generator causes a short-circuit failure can be considered. It is necessary to capture the change in the impedance of the internal winding of the generator when energized, but here, as a method of monitoring and measuring the impedance value of the conductor and power system in the energized state circuit, interorder harmonics are used. The method of measurement is known. For example, the following (conventional examples 1 to 3) are used to monitor changes in impedance using inter-order harmonics.

（１）従来例１「分散電源の保護装置およびそれを備えたシステム」（特許文献１参照）
従来例１は、電力系統における停電時に、マイクログリッドの給電設備（分散型電源）により自立運転を行う場合の保護技術に関し、特に短絡電流を防止し、分散型電源を保護するための保護装置およびそれを備えたシステムに関するものである。電力を供給する対象の設備には、停電により一時停止した後にも速やかに電力を供給する必要がある。そのような重要設備に、停電時に電力を供給するためにも分散型電源が使用されているが、この時、停電が自然災害によるもの等であると重要設備側で短絡事故が発生していると考えられる。 (1) Conventional Example 1 “Distributed power supply protection device and system provided with the same” (see Patent Document 1)
Conventional example 1 relates to a protection technique for self-sustaining operation by a microgrid power supply facility (distributed power supply) in the event of a power failure in the power system, and particularly covers a protection device for preventing short-circuit current and protecting the distributed power supply. It is about a system equipped with it. It is necessary to promptly supply electric power to the equipment to be supplied with electric power even after the equipment is temporarily stopped due to a power outage. Distributed power sources are also used to supply power to such important equipment in the event of a power outage, but at this time, if the power outage is due to a natural disaster, a short-circuit accident has occurred on the important equipment side. it is conceivable that.

そのため分散電源が配電を行うよりも前にマイクログリッドに高調波電源によって高調波を注入し、マイクログリッドでの短絡状態の系統インピーダンスを計測して回路内の短絡を検出するようになっている。 Therefore, before the distributed power supply distributes power, harmonics are injected into the microgrid by the harmonic power supply, and the system impedance in the short-circuited state on the microgrid is measured to detect the short-circuit in the circuit.

従来例１においては、電力系統内の停電によって一度系統から分散電源が切り離された回路内において次数間高調波を注入し、また短絡している箇所を検出しており、注入する回路に分散電源が含まれていないことが読み取れる。発電機内部インピーダンスの値を測定するための工夫がされていなく発電機内部インピーダンスの値を計測することはできなかった。 In Conventional Example 1, a harmonic between orders is injected in a circuit in which the distributed power supply is once disconnected from the system due to a power failure in the power system, and a short-circuited portion is detected, and the distributed power supply is injected into the circuit. It can be read that is not included. It was not possible to measure the value of the internal impedance of the generator because no device was devised to measure the value of the internal impedance of the generator.

（２）従来例２「分散電源の単独運転検出装置」（特許文献２参照）
従来例２は、配電系統の変更や他の単独運転検出装置の存否に拘らず、分散電源の単独運転を確実に、しかも配電系統に悪影響を及ぼすこともなく検出することのできる単独運転検出装置を提供することを主たる目的としている。従来例２では、次数間高調波注入による配電系統への悪影響を抑えるため、注入する次数間高調波電流値の自動調整を行うことで、同一系統内で、複数の監視対象がある場合においても、系統を乱さずに正確に分散電源の単独運転を検出することができる。しかし、後述するように発電機の故障を検出するためには、次数間高調波の発電機内部巻線に流入する電流値を一定に調整する、または、発電機の特性によって決まる電流値以上の電流を注入する必要があるため、従来例２を使って発電機内部故障を検出することはできない。 (2) Conventional Example 2 “Distributed power source independent operation detection device” (see Patent Document 2)
Conventional example 2 is a solitary operation detection device capable of reliably detecting the solitary operation of a distributed power source without adversely affecting the distribution system, regardless of the change of the distribution system or the presence or absence of another solitary operation detection device. The main purpose is to provide. In the conventional example 2, in order to suppress the adverse effect on the distribution system due to the injection of the interorder harmonics, the automatic adjustment of the interorder harmonic current value to be injected is performed even when there are a plurality of monitoring targets in the same system. , It is possible to accurately detect the isolated operation of the distributed power source without disturbing the system. However, as will be described later, in order to detect a generator failure, the current value flowing into the generator internal winding of the interorder harmonics is adjusted to a constant value, or the current value is equal to or higher than the current value determined by the characteristics of the generator. Since it is necessary to inject an electric current, it is not possible to detect an internal failure of the generator using the conventional example 2.

（３）従来例３「き電回路の保護装置」（特許文献３参照）
従来例３では、次数間高調波を交流き電回路の系統に重畳注入し、その次数間高調波電流の注入によって交流き電回路に生じた電圧電流歪みにより、交流き電回路の電気的特性値、例えば計測ライン間の次数間高調波のインピーダンス（またはその逆数のアドミタンス）を算出して監視する。次数間高調波を注入することによって、き電回路内の電圧波形の歪みから電気的特性やインピーダンスを検出し、き電回路内に短絡故障が発生した場合に回路の遮断を行い重大な事故かを事前に防ぐことを目的としている。しかし、後述するように発電機への注入電流の量によって発電機インピーダンスが変化するため、発電機部内巻線インピーダンスが変化することになり、従来例３の測定方法では発電機内部巻線の故障検出を行うことは出来ない。 (3) Conventional Example 3 “Protecting device for feeder circuit” (see Patent Document 3)
In the conventional example 3, the interorder harmonics are superposed and injected into the system of the AC electric circuit, and the electrical characteristics of the AC electric circuit are caused by the voltage-current distortion generated in the AC electric circuit by the injection of the interorder harmonic current. Calculate and monitor values, such as the impedance of interorder harmonics between measurement lines (or the admittance of their inverse). By injecting harmonics between orders, the electrical characteristics and impedance are detected from the distortion of the voltage waveform in the electric circuit, and if a short circuit failure occurs in the electric circuit, the circuit is cut off and it is a serious accident. The purpose is to prevent in advance. However, as will be described later, since the generator impedance changes depending on the amount of the injection current into the generator, the winding impedance in the generator section changes, and the measurement method of the conventional example 3 causes a failure of the winding inside the generator. It cannot be detected.

特開２０１９－１１０７１０号公報Japanese Unexamined Patent Publication No. 2019-110710 特開２００１－２５１７６８号公報Japanese Unexamined Patent Publication No. 2001-251768 特開２００４－０７４９２４号公報Japanese Unexamined Patent Publication No. 2004-074924

上述したように、従来の次数間高調波を利用したインピーダンス測定方法では、発電機内部巻線インピーダンスの正確な計測および、発電機内部故障の検出を行うことができない。 As described above, the conventional impedance measuring method using interorder harmonics cannot accurately measure the internal winding impedance of the generator and detect the internal failure of the generator.

以下、発電機内部巻線インピーダンスの特性について説明する。発電機内部巻線で発生した磁束は、発電機の回転子の鉄心や界磁巻線、ダンパー巻線等と鎖交している。発電機内部巻線のインダクタンスの量は、回転子の鉄心や界磁巻線、ダンパー巻線等へ鎖交する磁束の量によって変化するが、鎖交する磁束の量は発電機内部巻線に流入する電流量によっても変化する。そのため、発電機内部巻線インピーダンスの値を正確に計測するには、発電機内部巻線に流入する電流値を調整し、一定にすることによって、計測される発電機内部巻線のインダクタンスの大きさを一定化させる必要がある。 Hereinafter, the characteristics of the internal winding impedance of the generator will be described. The magnetic flux generated in the internal winding of the generator is interlinking with the iron core of the rotor of the generator, the field winding, the damper winding, and the like. The amount of inductance of the generator internal winding varies depending on the amount of magnetic flux interlinking the iron core of the rotor, field winding, damper winding, etc., but the amount of interlinking magnetic flux is in the generator internal winding. It also changes depending on the amount of inflowing current. Therefore, in order to accurately measure the value of the generator internal winding impedance, the current value flowing into the generator internal winding is adjusted and made constant, so that the measured inductance of the generator internal winding is large. It is necessary to make it constant.

しかしながら、従来の次数間高調波によるインピーダンス測定法では、このような発電機内部巻線インピーダンスの特性を考慮していない。 However, the conventional impedance measurement method using inter-order harmonics does not consider such characteristics of the internal winding impedance of the generator.

以下、発電機内部巻線インピーダンスと次数間高調波の注入量の実測結果について説明する。図３は、試験回路の概略を示す図である。 Hereinafter, the actual measurement results of the generator internal winding impedance and the injection amount of the interorder harmonics will be described. FIG. 3 is a diagram showing an outline of a test circuit.

図３に示す試験回路では、巻線を持つ発電機１０を使用し、次数間高調波注入装置１００より、一定の次数間高調波電流を発電機内部巻線のＵ－Ｗ間に注入し、注入電流を変えながら発電機内部巻線インピーダンス変化を測定した。発電機内部巻線に注入する次数間高調波電流の周波数は、試験に使用した発電機１０の定格周波数６０Ｈｚの２．６倍の１５６Ｈｚとしている。 In the test circuit shown in FIG. 3, a generator 10 having a winding is used, and a constant interorder harmonic current is injected between the U and W of the winding inside the generator from the interorder harmonic injection device 100. The change in the winding impedance inside the generator was measured while changing the injection current. The frequency of the interorder harmonic current injected into the internal winding of the generator is 156 Hz, which is 2.6 times the rated frequency of 60 Hz of the generator 10 used in the test.

発電機１０を実際に回転させ、次数間高調波注入装置１００から次数間高調波電流を注入し、次数間高調波注入時のＵ－Ｗ間電圧を電圧検出器１０２により検出し、ＵからＷへ流れる電流の次数間高調波成分を電流検出器１０１により検出し、周波数１５６Ｈｚにおける発電機巻線内部インピーダンスを測定する。この測定結果を図４に示す。 The generator 10 is actually rotated, the interorder harmonic current is injected from the interorder harmonic injection device 100, the UW voltage at the time of injecting the interorder harmonics is detected by the voltage detector 102, and U to W The interorder harmonic component of the current flowing to is detected by the current detector 101, and the internal impedance of the generator winding at a frequency of 156 Hz is measured. The measurement result is shown in FIG.

図４では、注入電流と発電機巻線内部インピーダンスの関係を示す図であり、縦軸が発電機巻線内部インピーダンス［Ω］、横軸が注入電流の電流値［Ａ］を示している。図４に示す通り、注入電流量が１Ａまでは、注入電流量の増加とともに計測される発電機内部巻線インピーダンス値も増加する。さらに注入電流量を増加させるとインピーダンス値は低下し、ある一定の値へ近づいていく。図４では、注入電流量が一定量以上になるとインピーダンス値は４０．０Ωの一定値になることがわかる。 FIG. 4 is a diagram showing the relationship between the injection current and the internal impedance of the generator winding. The vertical axis shows the internal impedance of the generator winding [Ω], and the horizontal axis shows the current value [A] of the injection current. As shown in FIG. 4, when the injection current amount is up to 1A, the generator internal winding impedance value measured increases as the injection current amount increases. When the injection current amount is further increased, the impedance value decreases and approaches a certain value. In FIG. 4, it can be seen that the impedance value becomes a constant value of 40.0Ω when the injection current amount becomes a certain amount or more.

ここで、従来の次数間高調波の課題として、以下のことがあげられる。 Here, the following can be mentioned as problems of the conventional inter-order harmonics.

図５は、発電機１０５が接続された電力系統に次数間高調波注入装置１０４から次数間高調波電流を注入している様子を示している。図５において、次数間高調波注入装置１０４より出力する電流量をＩｐ１とすると、電力系統との接続点で注入電流量Ｉｐ１は、発電機１０５の方向に分流する発電機側分流量Ｉｐ２と、電力系統の系統負荷１０３の方へと流れる系統側分流量Ｉｐ３に分流する。分流する発電機側分流量Ｉｐ２と系統側分流量Ｉｐ３の分流する割合は、Ｚ２とＺ３の逆比によって決まる。 FIG. 5 shows a state in which the interorder harmonic current is injected from the interorder harmonic injection device 104 into the power system to which the generator 105 is connected. In FIG. 5, assuming that the amount of current output from the interorder harmonic injection device 104 is Ip1, the injection current amount Ip1 at the connection point with the power system is the generator-side distribution flow Ip2 that diverges in the direction of the generator 105. It is diverted to the system side distribution flow Ip3 flowing toward the system load 103 of the power system. The ratio of the diversion of the generator side diversion flow rate Ip2 and the system side diversion flow rate Ip3 to be split is determined by the inverse ratio of Z2 and Z3.

電力系統１に次数間高調波電流を注入している場合、発電機側分流量Ｉｐ２は、電力系統側インピーダンスＺ３によって変化するが、電力系統側インピーダンスＺ３は、電力系統に接続されている系統負荷１０３のインピーダンスの影響を受ける。電力系統側インピーダンスＺ３は、系統負荷１０３の負荷量によって変化するため、発電機側注入電流Ｉｐ２が例えば図４に示すＸ，Ｙの幅で変化してしまう。 When the interorder harmonic current is injected into the power system 1, the generator-side partial flow Ip2 changes depending on the power system-side impedance Z3, but the power system-side impedance Z3 is the system load connected to the power system. It is affected by the impedance of 103. Since the impedance Z3 on the power system side changes depending on the load amount of the system load 103, the injection current Ip2 on the generator side changes in the widths of X and Y shown in FIG. 4, for example.

一方、発電機側分流量Ｉｐ２によって発電機内部巻線のインピーダンスの値が変化するため、発電機内部故障によるインピーダンス変化なのか、系統負荷量の変化によるインピーダンス変化なのか区別がつけられないため、発電機故障の発生をインピーダンス値をもとに検出することができない。 On the other hand, since the impedance value of the internal winding of the generator changes depending on the generator side flow rate Ip2, it is not possible to distinguish between the impedance change due to the internal failure of the generator and the impedance change due to the change in the system load. The occurrence of generator failure cannot be detected based on the impedance value.

本発明は、上記問題を解決するためになされたもので、次数間高調波電流を注入することで発電機内部巻線インピーダンスの値を算出し、確実に発電機内部故障を検出することができる発電機内部故障検出方法、発電機内部故障検出装置を提供することにある。 The present invention has been made to solve the above problem, and it is possible to calculate the value of the internal winding impedance of the generator by injecting a harmonic current between orders and reliably detect the internal failure of the generator. The purpose of the present invention is to provide a generator internal failure detection method and a generator internal failure detection device.

上記課題を解決するために、請求項１に対応する発明による発電機内部故障検出方法は、発電機が接続された電力系統に次数間高調波電流を注入し、電力系統の線間電圧波形と発電機の電流波形から注入した次数間高調波電流と同じ周波数における電圧成分の電圧値と電流成分の電流値を検出し、前記電圧値と前記電流値から発電機内部巻線インピーダンス値を計算し、計算された発電機内部巻線インピーダンス値が故障を判断する所定値を下回るかどうかにより、発電機内部巻線の短絡による発電機内部故障を検出する発電機内部故障検出方法であって、検出された電流値が一定の値となるように前記次数間高調波電流の注入量を可変にする。 In order to solve the above problem, the generator internal failure detection method according to the invention according to claim 1 injects an interorder harmonic current into the power system to which the generator is connected, and obtains a line voltage waveform of the power system. The voltage value of the voltage component and the current value of the current component at the same frequency as the interorder harmonic current injected from the current waveform of the generator are detected, and the generator internal winding impedance value is calculated from the voltage value and the current value. , A generator internal failure detection method that detects a generator internal failure due to a short circuit in the generator internal winding depending on whether the calculated generator internal winding impedance value is below the predetermined value for determining the failure. The injection amount of the interorder harmonic current is made variable so that the applied current value becomes a constant value.

請求項２に対応する発明による発電機内部故障検出方法は、発電機が接続された電力系統に次数間高調波電流を注入し、電力系統の線間電圧波形と発電機の電流波形から注入した次数間高調波と同じ周波数における電圧成分の電圧値と電流成分の電流値を検出し、前記電圧値と前記電流値から発電機内部巻線インピーダンス値を計算し、計算された発電機内部巻線インピーダンス値が故障を判断する所定値を下回るかどうかにより、発電機内部巻線の短絡による発電機内部故障を検出する発電機内部故障検出方法であって、前記電力系統に予め設定された量の次数間高調波電流を注入する。 In the generator internal failure detection method according to the second aspect of the present invention, an interorder harmonic current is injected into the power system to which the generator is connected, and the current is injected from the line voltage waveform of the power system and the current waveform of the generator . The voltage value of the voltage component and the current value of the current component at the same frequency as the interorder harmonics are detected, the generator internal winding impedance value is calculated from the voltage value and the current value, and the calculated generator internal winding A generator internal failure detection method that detects a generator internal failure due to a short circuit in the generator internal winding depending on whether the impedance value is below a predetermined value for determining the failure, and is an amount preset for the power system. Inject harmonic current between orders.

請求項３に対応する発明による発電機内部故障検出方法は、請求項１または請求項２において、前記発電機内部巻線インピーダンス値の時間変化率が、予め設定されたしきい値を超えた場合に発電機内部故障と判定する。 The generator internal failure detection method according to the third aspect of the present invention is the case where the time change rate of the generator internal winding impedance value exceeds a preset threshold value in claim 1 or 2. Judged as an internal failure of the generator.

請求項４に対応する発明による発電機内部故障検出方法は、請求項２において、次数間高調波の注入電流量に対する故障していないときの発電機内部巻線インピーダンス値と、注入した次数間高調波と同じ周波数における電圧成分と電流成分を電力系統の線間電圧波形と電流波形から抽出し、抽出された電圧成分の電圧値と電流成分の電流値から計算した発電機内部巻線インピーダンス値とを比較することで発電機内部故障を検出する。 The method for detecting an internal failure of a generator according to the invention according to claim 4 is the method of detecting the internal failure of the generator according to claim 2, wherein the generator internal winding impedance value when there is no failure with respect to the injection current amount of the interorder harmonics and the injected order. The voltage component and current component at the same frequency as the harmonics are extracted from the line voltage waveform and current waveform of the power system, and the generator internal winding impedance value calculated from the voltage value of the extracted voltage component and the current value of the current component. The internal failure of the generator is detected by comparing with.

請求項５に対応する発明による発電機内部故障検出方法は、請求項１～４の何れかにおいて、三相以上の電力系統において、それぞれの相に注入する次数間高調波電流の周波数を異なる周波数に設定し、それぞれの相について発電機内部故障を検出する。 In the generator internal failure detection method according to the invention according to claim 5, in any one of claims 1 to 4, in a power system having three or more phases, the frequency of the interorder harmonic current injected into each phase is different. Is set to, and the generator internal failure is detected for each phase.

請求項６に対応する発明による発電機内部故障検出装置は、発電機が接続された電力系統に次数間高調波電流を注入する次数間高調波注入装置と、電力系統の線間電圧波形と電流波形から注入した次数間高調波と同じ周波数における電圧成分の電圧値と電流成分の電流値を検出する電圧・電流検出装置と、前記電圧値と前記電流値から発電機内部巻線インピーダンス値を計算するインピーダンス算出器と、前記発電機内部巻線インピーダンス値が故障を判断する所定値を下回るかどうかにより、発電機内部巻線の短絡による発電機内部故障を判定する故障判定器と、前記電圧・電流検出装置によって検出された前記電流成分の電流値が一定の値となるように前記次数間高調波注入装置を制御する注入電流制御装置とを有する。 The generator internal failure detection device according to the invention according to claim 6 includes an interorder harmonic injection device that injects an interorder harmonic current into the power system to which the generator is connected, and a line voltage waveform and current of the power system. A voltage / current detector that detects the voltage value of the voltage component and the current value of the current component at the same frequency as the interorder harmonic injected from the waveform, and the generator internal winding impedance value is calculated from the voltage value and the current value. An impedance calculator that determines the internal failure of the generator due to a short circuit in the internal winding of the generator depending on whether the impedance value of the internal winding of the generator is lower than a predetermined value for determining the failure, and the voltage. It has an injection current control device that controls the interorder harmonic injection device so that the current value of the current component detected by the current detection device becomes a constant value.

請求項７に対応する発明による発電機内部故障検出装置は、発電機が接続された電力系統に次数間高調波電流を注入する次数間高調波注入装置と、電力系統の線間電圧波形と電流波形から注入した次数間高調波と同じ周波数における電圧成分の電圧値と電流成分の電流値を検出する電圧・電流検出装置と、前記電圧値と前記電流値から発電機内部巻線インピーダンス値を計算するインピーダンス算出器と、前記発電機内部巻線インピーダンス値が故障を判断する所定値を下回るかどうかにより、発電機内部巻線の短絡による発電機内部故障を判定する故障判定器と、前記電力系統に予め設定された量の次数間高調波電流を注入するように前記次数間高調波注入装置を制御する注入電流制御装置とを有する。 The generator internal failure detection device according to the invention according to claim 7 includes an interorder harmonic injection device that injects an interorder harmonic current into the power system to which the generator is connected, and a line voltage waveform and current of the power system. A voltage / current detector that detects the voltage value of the voltage component and the current value of the current component at the same frequency as the interorder harmonic injected from the waveform, and the generator internal winding impedance value is calculated from the voltage value and the current value. An impedance calculator, a failure determiner for determining an internal generator failure due to a short circuit in the generator internal winding, and the power system depending on whether the generator internal winding impedance value is lower than a predetermined value for determining the failure. It has an injection current control device that controls the interorder harmonic injection device so as to inject a preset amount of interorder harmonic current.

本発明では、次数間高調波電流を注入することで発電機内部巻線インピーダンスの値を算出し、確実に発電機内部故障を検出することができる発電機内部故障検出方法、発電機内部故障検出装置を提供することができる。 In the present invention, a generator internal failure detection method and a generator internal failure detection method capable of calculating the value of the generator internal winding impedance by injecting an interorder harmonic current and reliably detecting the generator internal failure. The device can be provided.

本実施形態における発電機内部故障検出装置の構成を示す図。The figure which shows the structure of the generator internal failure detection apparatus in this embodiment. 比率差動継電器の検出原理を説明するための図。The figure for demonstrating the detection principle of a ratio differential relay. 発電機内部巻線インピーダンスと次数間高調波の注入量の実測に用いた試験回路の概略を示す図。The figure which shows the outline of the test circuit used for the actual measurement of the generator internal winding impedance and the injection amount of inter-order harmonics. 注入電流と発電機巻線内部インピーダンスの関係を示す図。The figure which shows the relationship between the injection current and the internal impedance of a generator winding. 発電機が接続された電力系統に次数間高調波注入装置から次数間高調波電流を注入している様子を示す図。The figure which shows the state of injecting the interorder harmonic current from the interorder harmonic injection device into the electric power system to which a generator is connected.

以下、本発明の実施の形態について図を参照して説明する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

図１は、本実施形態における発電機内部故障検出装置３の構成を示す図である。図１に示すように、発電機内部故障検出装置３は、電力系統１に接続され、電力系統１に発電機２が接続されている。発電機内部故障検出装置３は、電圧・電流検出装置６、注入電流制御装置７、次数間高調波注入装置８、インピーダンス算出器９、故障判定器１０を有している。 FIG. 1 is a diagram showing a configuration of a generator internal failure detection device 3 in the present embodiment. As shown in FIG. 1, the generator internal failure detection device 3 is connected to the power system 1, and the generator 2 is connected to the power system 1. The generator internal failure detection device 3 includes a voltage / current detection device 6, an injection current control device 7, an inter-order harmonic injection device 8, an impedance calculator 9, and a failure determination device 10.

［次数間高調波電流の注入］
次数間高調波注入装置８は、電力系統１の基本周波数の非整数倍の次数間高調波電流を電力系統１に注入する装置である。電圧・電流検出装置６は、次数間高調波注入装置８よりも発電機側で電力系統１と接続され、電力系統１の電流値及び線間電圧値を計測し、その次数間高調波成分を検出する装置である。電力系統１に次数間高調波電流を注入した際、電力系統１及び監視対象である発電機２の線間電圧には次数間高調波成分が加算されることになる。 [Injection of harmonic current between orders]
The inter-degree harmonic injection device 8 is a device that injects an inter-degree harmonic current that is a non-integer multiple of the fundamental frequency of the power system 1 into the power system 1. The voltage / current detection device 6 is connected to the power system 1 on the generator side of the interorder harmonic injection device 8, measures the current value and the line voltage value of the power system 1, and determines the interorder harmonic component. It is a device to detect. When the interorder harmonic current is injected into the power system 1, the interorder harmonic component is added to the line voltage of the power system 1 and the generator 2 to be monitored.

電圧・電流検出装置６は、計器用変流器４を介して電力系統１から電流を取り込み、また計器用変圧器５を介して電力系統１から電圧を取り込んでいる。 The voltage / current detection device 6 takes in current from the power system 1 via the voltage transformer 4 and takes in voltage from the power system 1 via the voltage transformer 5.

ここで、電力系統１に注入された次数間高調波電流の分流について説明する。次数間高調波注入装置８から電力系統１に注入した次数間高調波電流の電流量を注入電流量Ｉｐ１とすると、注入電流量Ｉｐ１は、電力系統１との接続点で、発電機２の方向に分流する発電機側分流量Ｉｐ２と、電力系統１の系統側負荷１１の方へと流れる系統側分流量Ｉｐ３に分流する。 Here, the shunt current of the interorder harmonic current injected into the power system 1 will be described. Assuming that the current amount of the interorder harmonic current injected into the power system 1 from the interorder harmonic injection device 8 is the injection current amount Ip1, the injection current amount Ip1 is the direction of the generator 2 at the connection point with the power system 1. The current is divided into the generator-side current flow Ip2 and the system-side current Ip3 that flows toward the system-side load 11 of the power system 1.

［電流・電圧検出、周波数分析］
電圧・電流検出装置６は、計器用変圧器５を介して電力系統１から電圧を取り込んで発電機線間電圧波形を検出し、検出された電圧波形の周波数分析を行う。また、電圧・電流検出装置６は、電力系統１の基本波や電力系統１に接続された負荷等および発電機２が発生する高調波と、次数間高調波注入装置８によって注入された次数間高調波が組み合わされた合成波から、注入した次数間高調波と同じ周波数の電圧成分を抽出して電圧値を検出する。 [Current / voltage detection, frequency analysis]
The voltage / current detection device 6 takes in voltage from the power system 1 via the voltage transformer 5, detects the voltage waveform between the generator lines, and performs frequency analysis of the detected voltage waveform. Further, the voltage / current detection device 6 is used between the fundamental wave of the power system 1, the load connected to the power system 1, the harmonics generated by the generator 2, and the order injected by the interorder harmonic injection device 8. A voltage component having the same frequency as the injected interorder harmonics is extracted from the combined harmonics to detect the voltage value.

同様にして、電圧・電流検出装置６は、次数間高調波注入装置８によって注入された次数間高調波と同じ周波数の電流成分を抽出するために、計器用変流器４を介して電力系統１から電流を取り込んで電流波形を検出し、検出された電流波形について周波数分析を行う。電圧・電流検出装置６は、注入された次数間高調波と同じ周波数の電流成分を抽出することによって、発電機側分流量Ｉｐ２の電流値を検出する。 Similarly, the voltage / current detector 6 powers the power system via the instrument current transformer 4 in order to extract a current component having the same frequency as the interorder harmonics injected by the interorder harmonic injection device 8. The current is taken in from 1 to detect the current waveform, and the detected current waveform is subjected to frequency analysis. The voltage / current detection device 6 detects the current value of the generator-side partial flow rate Ip2 by extracting a current component having the same frequency as the injected interorder harmonics.

なお、前述した説明では、計器用変圧器５及び計器用変流器４を介して、電圧・電流検出器６が電力系統１より電圧・電流を取り込むとしているが、電圧・電流検出器６が電力系統１より電圧・電流を取り込める構成を有していれば、必要に応じて計器用変圧器５及び計器用変流器４を省略する、または何れか一方を省略しても良い。 In the above description, the voltage / current detector 6 takes in the voltage / current from the power system 1 via the instrument transformer 5 and the instrument transformer 4, but the voltage / current detector 6 takes in the voltage / current. If the voltage / current can be taken in from the power system 1, the instrument transformer 5 and the instrument transformer 4 may be omitted, or one of them may be omitted, if necessary.

［注入電流制御］
発電機内部巻線に流入する次数間高調波電流の量は系統インピーダンスＺ３の大きさによって変化し、従来例の課題で述べたように、発電機内部故障だけではなく、系統インピーダンスによっても発電機内部巻線インピーダンスの計測値は変動する。図４において、Ｘは、系統インピーダンスＺ３の変動に起因する発電機側分流量Ｉｐ２の変動幅の一例を示している。そのため、発電機内部巻線に流入する電流値を一定に保つ必要がある。 [Injection current control]
The amount of interorder harmonic current flowing into the internal winding of the generator changes depending on the magnitude of the system impedance Z3, and as described in the problem of the conventional example, the generator depends not only on the internal failure of the generator but also on the system impedance. The measured value of the internal winding impedance fluctuates. In FIG. 4, X shows an example of the fluctuation range of the generator-side partial flow rate Ip2 due to the fluctuation of the system impedance Z3. Therefore, it is necessary to keep the value of the current flowing into the winding inside the generator constant.

注入電流制御装置７は、発電機内部巻線に流入する電流値が一定となるように、次数間高調波注入装置８が出力する注入電流量Ｉｐ１を可変にするための制御をする。 The injection current control device 7 controls to make the injection current amount Ip1 output by the interorder harmonic injection device 8 variable so that the current value flowing into the internal winding of the generator becomes constant.

電圧・電流検出装置６は、発電機側分流量Ｉｐ２の値を注入電流制御装置７に与える。一定に保つべき発電機側分流量を発電機側分流量基準値Ｉｐ２’とすると、注入電流制御装置７は、発電機側分流量基準値Ｉｐ２’と、算出された発電機側分流量Ｉｐ２の差をもとに次数間高調波の注入電流量Ｉｐ１を決定し、決定した注入量を指令値として次数間高調波注入装置８に与える。次数間高調波注入装置８は、注入電流制御装置７から与えられた指令値に基づいて注入電流量Ｉｐ１を出力する。 The voltage / current detection device 6 gives the value of the generator-side partial flow rate Ip2 to the injection current control device 7. Assuming that the generator-side distribution reference value Ip2'that should be kept constant is the generator-side distribution reference value Ip2', the injection current control device 7 has the generator-side distribution reference value Ip2'and the calculated generator-side distribution Ip2. The injection current amount Ip1 of the interorder harmonics is determined based on the difference, and the determined injection amount is given to the interorder harmonic injection device 8 as a command value. The inter-order harmonic injection device 8 outputs the injection current amount Ip1 based on the command value given by the injection current control device 7.

［インピーダンス算出］
一方、インピーダンス算出器９は、電圧・電流検出装置６によって抽出された次数間高調波注入装置８の注入電流と同じ周波数の電圧成分と電流成分を用いて、発電機内部巻線インピーダンスを算出する。 [Impedance calculation]
On the other hand, the impedance calculator 9 calculates the generator internal winding impedance using the voltage component and the current component having the same frequency as the injection current of the interorder harmonic injection device 8 extracted by the voltage / current detection device 6. ..

［第１の故障判定方法］
故障判定器１０は、インピーダンス算出器９で算出された発電機内部巻線インピーダンスの値が、発電機２が故障と判断される発電機内部巻線インピーダンスのしきい値を下回った場合、発電機内部故障状態であると判断し、故障信号を発報する。 [First failure determination method]
The failure determiner 10 is a generator when the value of the generator internal winding impedance calculated by the impedance calculator 9 is lower than the threshold value of the generator internal winding impedance determined by the generator 2 to be a failure. Judges that it is in an internal failure state and issues a failure signal.

［第２の故障判定方法］
第１の故障判定方法では、注入電流制御装置７によって注入電流量Ｉｐ１を調整することで、発電機側分流量Ｉｐ２の値を発電機側分流量基準値Ｉｐ２’となるように保ちつつ発電機内部巻線インピーダンスの値を算出していたが、第２の故障判定方法では、注入電流量Ｉｐ１の値を以下に述べるように予め設定された量に一定に保つことでも、発電機内部故障を監視する。 [Second failure determination method]
In the first failure determination method, the injection current amount Ip1 is adjusted by the injection current control device 7, so that the value of the generator side distribution flow Ip2 is kept at the generator side distribution reference value Ip2'. The value of the internal winding impedance was calculated, but in the second failure determination method, the internal failure of the generator can be prevented by keeping the value of the injection current amount Ip1 constant at the preset amount as described below. Monitor.

図４に示した通り、注入電流量の値を大きくした場合、一定の発電機内部巻線インピーダンスの値へ収束していく特性がある。この時、収束した発電機内部巻線インピーダンス値をとる最小の注入電流をＩｐ２ｍｉｎとする。電力系統１の負荷側インピーダンスＺ３の変動によって発電機側分流量Ｉｐ２が変動しても、その最小値が注入電流Ｉｐ２ｍｉｎよりも大きければ、発電機内部巻線インピーダンスは発電機側分流量Ｉｐ２の変動によらず一定の値が計測される。 As shown in FIG. 4, when the value of the injection current amount is increased, there is a characteristic that the value of the internal winding impedance of the generator converges to a certain value. At this time, the minimum injection current that takes the converged generator internal winding impedance value is Ip2min. Even if the generator side partial flow Ip2 fluctuates due to the fluctuation of the load side impedance Z3 of the power system 1, if the minimum value is larger than the injection current Ip2min, the generator internal winding impedance fluctuates the generator side partial flow Ip2. A constant value is measured regardless.

このように、第２の故障判定方法では、発電機側分流量Ｉｐ２が電力系統１の負荷側インピーダンスＺ３が変動しても発電機内部巻線インピーダンスが一定の値で計測出来る予め設定された量、すなわち最小の注入電流Ｉｐ２ｍｉｎよりも大きい値となるように、次数間高調波注入装置８の注入電流量Ｉｐ１を設定する。これにより、故障していない発電機２の発電機内部巻線インピーダンスが正確に計測できるので、発電機内部故障を検出することができる。 As described above, in the second failure determination method, the generator internal winding impedance can be measured at a constant value even if the load side impedance Z3 of the power system 1 fluctuates in the generator side current flow Ip2, which is a preset amount. That is, the injection current amount Ip1 of the interorder harmonic injection device 8 is set so as to have a value larger than the minimum injection current Ip2min. As a result, the generator internal winding impedance of the generator 2 that has not failed can be accurately measured, so that the generator internal failure can be detected.

なお、注入電流量Ｉｐ１を最小の注入電流Ｉｐ２ｍｉｎよりも大きい値に一定に保つだけでなく、最小の注入電流Ｉｐ２ｍｉｎよりも大きい値に設定されるのであれば注入電流量Ｉｐ１が変動しても良い。 Not only the injection current amount Ip1 is kept constant at a value larger than the minimum injection current Ip2min, but also the injection current amount Ip1 may fluctuate if it is set to a value larger than the minimum injection current Ip2min. ..

［第１の変形例］
前述した第１の故障判定方法及び第２の故障判定方法では、故障判定器１０は、インピーダンス算出器９によって算出された発電機内部巻線インピーダンス値がしきい値を下回った場合に、発電機内部故障状態であると判断して故障信号を発報しているが、別の故障状態の判定方法を用いることも可能である。 [First modification]
In the first failure determination method and the second failure determination method described above, the failure determination device 10 is a generator when the generator internal winding impedance value calculated by the impedance calculator 9 falls below the threshold value. Although it is determined that it is in an internal failure state and a failure signal is issued, it is also possible to use another method for determining the failure state.

例えば、故障判定器１０は、インピーダンス算出器９によって算出された発電機内部巻線インピーダンス値の時間変化率が、時間変化率に対する予め設定されたしきい値を超えた場合に、発電機内部故障とみなすように構成することも可能である。 For example, the failure determination device 10 causes a generator internal failure when the time change rate of the generator internal winding impedance value calculated by the impedance calculator 9 exceeds a preset threshold value for the time change rate. It is also possible to configure it to be regarded as.

発電機内部巻線インピーダンスの値は、熱等による影響によって変化するが、発電機内部短絡状態における発電機内部巻線インピーダンス値の変化速度は熱等によるものよりも早いので、このように発電機内部巻線インピーダンスの時間変化率により故障を判定することで、熱等によるインピーダンス変化を故障として誤判断することを防止できる。 The value of the internal winding impedance of the generator changes due to the influence of heat, etc., but the rate of change of the internal winding impedance value of the generator in the short-circuited state inside the generator is faster than that due to heat, etc. By determining the failure based on the time change rate of the internal winding impedance, it is possible to prevent the impedance change due to heat or the like from being erroneously determined as a failure.

［第２の変形列］
前述した第２の故障判定方法では、注入電流量Ｉｐ１を調整して、発電機側分流量Ｉｐ２を最小の注入電流Ｉｐ２ｍｉｎよりも大きい値に設定するとしているが、発電機側分流量Ｉｐ２が最小の注入電流Ｉｐ２ｍｉｎを下回っても発電機内部故障を検出できるようにする。 [Second transformation column]
In the second failure determination method described above, the injection current amount Ip1 is adjusted to set the generator-side partial flow Ip2 to a value larger than the minimum injection current Ip2min, but the generator-side partial flow Ip2 is the minimum. It is possible to detect an internal failure of the generator even if the injection current is less than Ip2min.

例えば、故障判定器１０は、予め、故障していない発電機２における次数間高調波の注入電流量と発電機内部巻線インピーダンス値との関係を計測し、その結果を発電機内部巻線インピーダンスデータとして保管しておく。故障判定器１０は、電圧・電流検出器６で検出された電流値Ｉｐ２のときの発電機内部巻線インピーダンス値を、発電機内部巻線インピーダンスデータから読み出す。 For example, the failure determiner 10 measures in advance the relationship between the injection current amount of the interorder harmonics in the generator 2 that has not failed and the generator internal winding impedance value, and obtains the result as the generator internal winding impedance. Save it as data. The failure determiner 10 reads out the generator internal winding impedance value at the current value Ip2 detected by the voltage / current detector 6 from the generator internal winding impedance data.

このように構成した発電機内部故障検出装置３では、発電機側分流量Ｉｐ２が最小の注入電流Ｉｐ２ｍｉｎを下回っても、故障していない場合の発電機２の発電機内部巻線インピーダンスが、発電機内部巻線インピーダンスデータから発電機側抽入量Ｉｐ２に応じて把握することができる。故障判定器１０は、発電機側分流量Ｉｐ２に応じた発電機内部巻線インピーダンスデータが示す値と、インピーダンス算出器９で算出された発電機内部巻線インピーダンスの値とを比較し、値が相違していれば発電機内部故障状態であると判断することができる。 In the generator internal failure detection device 3 configured in this way, even if the generator side distribution flow Ip2 falls below the minimum injection current Ip2min, the generator internal winding impedance of the generator 2 when there is no failure is generated. It can be grasped from the internal winding impedance data of the machine according to the extraction amount Ip2 on the generator side. The failure determiner 10 compares the value indicated by the generator internal winding impedance data according to the generator side flow rate Ip2 with the value of the generator internal winding impedance calculated by the impedance calculator 9, and the value is determined. If they are different, it can be determined that the generator is in an internal failure state.

［第３の変形例］
三相以上の電力系統１に本実施形態における発電機内部故障検出装置３を適用する場合には、前述した発電機内部故障検出方法を各相それぞれに適用する。その際には、次数間高調波注入装置８から各相に注入する次数間高調波電流の周波数を、それぞれ異なる周波数に設定する。これにより、相毎に前述した故障判定を実施することで、それぞれの相の発電機内部故障を個別に検出することができる。 [Third variant]
When the generator internal failure detection device 3 of the present embodiment is applied to the power system 1 having three or more phases, the above-mentioned generator internal failure detection method is applied to each phase. At that time, the frequencies of the interorder harmonic currents injected into each phase from the interorder harmonic injection device 8 are set to different frequencies. As a result, by carrying out the above-mentioned failure determination for each phase, it is possible to individually detect the internal failure of the generator in each phase.

［まとめ］
このようにして、本実施形態における発電機内部故障検出装置３（発電機内部故障検出方法）によれば、発電機内部巻線に次数間高調波電流を注入することで発電機内部巻線インピーダンスの値を算出し、確実に発電機内部故障を検出することができる。これにより、異相間短絡だけでなく、同相間短絡状態が起こることによる故障を検出することができる。 [summary]
In this way, according to the generator internal failure detection device 3 (generator internal failure detection method) in the present embodiment, the generator internal winding impedance is obtained by injecting an interorder harmonic current into the generator internal winding. It is possible to calculate the value of and reliably detect the internal failure of the generator. This makes it possible to detect not only a short circuit between different phases but also a failure due to a short circuit between different phases.

また、本実施形態における発電機内部故障検出装置３によれば、発電機内部巻線に注入する次数間高調波の電流量を一定にする（第１の故障判定方法）、あるいは発電機内部巻線インピーダンスの算出値が次数間高調波の注入量の変動によらず一定となる注入量以上にすることで（第２の故障判定方法）、発電機内部巻線インピーダンスを正確に測定できるようにして、発電機内部巻線の故障を検出することができる。 Further, according to the generator internal failure detection device 3 in the present embodiment, the current amount of the interorder harmonics injected into the generator internal winding is made constant (first failure determination method), or the generator internal winding. By making the calculated value of the line impedance equal to or greater than the injection amount that is constant regardless of the fluctuation of the injection amount of the harmonics between orders (second failure determination method), the internal winding impedance of the generator can be measured accurately. Therefore, it is possible to detect a failure of the winding inside the generator.

なお、本発明は上記各実施形態そのままに限定されるものではなく、実施段階ではその要旨を逸脱しない範囲で構成要素を変形して具体化できる。また、上記各実施形態に開示されている複数の構成要素の適宜な組み合わせにより、種々の発明を形成できる。例えば、実施形態に示される全構成要素から幾つかの構成要素を削除してもよい。さらに、異なる実施形態にわたる構成要素を適宜組み合わせてもよい。 It should be noted that the present invention is not limited to each of the above embodiments as it is, and at the implementation stage, the components can be modified and embodied within a range that does not deviate from the gist thereof. In addition, various inventions can be formed by an appropriate combination of the plurality of components disclosed in each of the above embodiments. For example, some components may be removed from all the components shown in the embodiments. In addition, components across different embodiments may be combined as appropriate.

１…電力系統、２…発電機、３…発電機内部故障検出装置、４…計器用変流器、５…計器用変圧器、６…電圧・電流検出装置、７…注入電流制御装置、８…次数間高調波注入装置、９…インピーダンス算出器、１０…故障判定器、１１…系統側負荷。 1 ... Power system, 2 ... Generator, 3 ... Generator internal failure detector, 4 ... Instrument current transformer, 5 ... Instrument transformer, 6 ... Voltage / current detector, 7 ... Injection current control device, 8 ... Inter-order harmonic injection device, 9 ... Impedance calculator, 10 ... Failure determiner, 11 ... System side load.

Claims

The interorder harmonic current is injected into the power system to which the generator is connected, and the voltage value of the voltage component and the current of the current component at the same frequency as the interorder harmonic current injected from the line voltage waveform and current waveform of the power system. The value is detected, the generator internal winding impedance value is calculated from the voltage value and the current value , and depending on whether the calculated generator internal winding impedance value is below the predetermined value for determining failure, the inside of the generator It is a generator internal failure detection method that detects a generator internal failure due to a short circuit in the winding , and it is a method to make the injection amount of the interorder harmonic current variable so that the detected current value becomes a constant value. A characteristic generator internal failure detection method.

The interorder harmonic current is injected into the power system to which the generator is connected, and the voltage value of the voltage component and the current value of the current component at the same frequency as the line voltage waveform of the power system and the order harmonic injected from the current waveform. Is detected, the generator internal winding impedance value is calculated from the voltage value and the current value, and the generator internal winding is determined by whether the calculated generator internal winding impedance value is lower than the predetermined value for determining the failure. A generator internal failure detection method for detecting a generator internal failure due to a short circuit of a wire, which comprises injecting a preset amount of interorder harmonic current into the power system. ..

The generator according to claim 1 or 2, wherein the generator internal failure is determined when the time change rate of the generator internal winding impedance value exceeds a preset threshold value. Internal failure detection method.

The line voltage waveform and current of the power system are the same as the generator internal winding impedance value when there is no failure with respect to the injected current amount of the interorder harmonics, and the voltage and current components at the same frequency as the injected interorder harmonics. 2 . _ The generator internal failure detection method described.

Claims 1 to 4, wherein in a power system having three or more phases, the frequency of the interorder harmonic current injected into each phase is set to a different frequency, and an internal failure of the generator is detected for each phase. The generator internal failure detection method described in any one.

An interorder harmonic injection device that injects interorder harmonic currents into the power system to which the generator is connected, and
A voltage / current detector that detects the voltage value of the voltage component and the current value of the current component at the same frequency as the interorder harmonics injected from the line voltage waveform and current waveform of the power system.
An impedance calculator that calculates the generator internal winding impedance value from the voltage value and the current value,
A failure determiner that determines a generator internal failure due to a short circuit in the generator internal winding depending on whether the generator internal winding impedance value is lower than a predetermined value for determining a failure.
A generator internal failure detection device including an injection current control device that controls the interorder harmonic injection device so that the current value of the current component detected by the voltage / current detection device becomes a constant value.

An interorder harmonic injection device that injects interorder harmonic currents into the power system to which the generator is connected, and
A voltage / current detector that detects the voltage value of the voltage component and the current value of the current component at the same frequency as the interorder harmonics injected from the line voltage waveform and current waveform of the power system.
An impedance calculator that calculates the generator internal winding impedance value from the voltage value and the current value,
A failure determiner that determines a generator internal failure due to a short circuit in the generator internal winding depending on whether the generator internal winding impedance value is lower than a predetermined value for determining a failure.
A generator internal failure detection device having an injection current control device that controls the interorder harmonic injection device so as to inject a preset amount of interorder harmonic current into the power system.