JP2008032587A - Ae sensor using interference-type optical fiber, and partial discharge measuring device by ae sensor - Google Patents

Ae sensor using interference-type optical fiber, and partial discharge measuring device by ae sensor Download PDF

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JP2008032587A
JP2008032587A JP2006207512A JP2006207512A JP2008032587A JP 2008032587 A JP2008032587 A JP 2008032587A JP 2006207512 A JP2006207512 A JP 2006207512A JP 2006207512 A JP2006207512 A JP 2006207512A JP 2008032587 A JP2008032587 A JP 2008032587A
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optical fiber
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Yasuhiro Yoshioka
靖浩 吉岡
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Meidensha Corp
Meidensha Electric Manufacturing Co Ltd
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Meidensha Electric Manufacturing Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To discriminate surely between the vibration noise and signal generated from partial discharge, and moreover, to clearly detect partial discharge generation in each phase. <P>SOLUTION: The tip part of an irradiation optical fiber 32 is allowed to penetrate the top part of a case body 31, in a state where the case body 31 having a bowl-type shape is turned down, and facing a space part 33 of the case body 31, and then the fiber 32 is fixed at a penetration part. A measuring surface member 34, that is to be mounted close to a mold part of a transformer for an mold type instrument, is provided on an opening face of the case body 31. A reflection optical fiber 35 is disposed close to the space part 33 side of the case body 31 of the measuring surface member 34, at a fixed distance from the tip part of the fiber 32. A half mirror 36 is disposed on the optical axis at the end of the fiber 32. When the measuring surface member 34 is mounted on the mold part of the transformer, ultrasonic vibrations generated following the generation of PD in the mold part are transmitted to the space part 33, and a beam from the fiber 32 is changed. The degree of the beam change is detected as the PD. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

この発明は、モールド型計器用変圧器（変成器）等の電力機器で発生する部分放電を検出する干渉型光ファイバーを用いたＡＥセンサ及びこのＡＥセンサによる部分放電計測装置に関するものである。   The present invention relates to an AE sensor using an interference type optical fiber for detecting a partial discharge generated in a power device such as a molded-type instrument transformer (transformer), and a partial discharge measuring apparatus using the AE sensor.

モールド型計器用変圧器（変成器）は、モールド絶縁材料で被覆されているので、その絶縁材料内部に微小な空隙状欠陥部（ボイド）や剥離などがあると、運転時にその部分に電界が集中し、部分放電（以下ＰＤと称する）と呼ばれる微弱な放電が発生する。また、モールド絶縁材料表面の汚損の影響によってもＰＤが発生することがある。   Since a molded-type instrument transformer (transformer) is coated with a mold insulating material, if there are minute voids (voids) or delamination inside the insulating material, an electric field is applied to that part during operation. A weak discharge called partial discharge (hereinafter referred to as PD) is generated. PD may also occur due to the influence of contamination on the surface of the mold insulating material.

特に、後者の場合には、汚損を除去すれば、ＰＤを防止できるけれども、前者の場合のＰＤは、防止ができず、回復性はない。ＰＤが発生した状態で運転を継続すると、ボイドや剥離状態を進展させる恐れがあり、最終的には、絶縁破壊に至る危険性がある。   In particular, in the latter case, PD can be prevented by removing contamination, but the PD in the former case cannot be prevented and is not recoverable. If the operation is continued in a state where PD is generated, there is a risk that a void or a peeled state may be developed, and there is a risk of eventually leading to dielectric breakdown.

このため、計器用変圧器（変成器）を使用する前に、事前にＰＤの発生があるかを検出測定しておけば、上記のような不具合を防止することができる。このような検出測定手段として、次のような３つの手法がある。   For this reason, if the occurrence of PD is detected and measured in advance before using the instrument transformer (transformer), the above-described problems can be prevented. As such detection and measurement means, there are the following three methods.

（ａ）変圧器（供試体）の主回路に直接カップリングコンデンサ（ＣＣ）を接続し、ＰＤ発生に伴う電圧変動からＰＤを検出する電気的手法（ＣＣ法）、
（ｂ）接地線に高周波ＣＴを取り付けて（接地線電流方式）、ＰＤの発生を漏れ電流として測定する電気的手法（高周波ＣＴ法）、
（ｃ）ＰＤ発生に伴う弾性波振動や放電音を音響的に検出する診断測定手法がある。 (A) An electrical method (CC method) in which a coupling capacitor (CC) is directly connected to the main circuit of a transformer (specimen), and PD is detected from voltage fluctuation accompanying PD generation,
(B) An electrical method (high frequency CT method) in which high frequency CT is attached to the ground wire (ground wire current method) and the occurrence of PD is measured as a leakage current;
(C) There is a diagnostic measurement method for acoustically detecting elastic wave vibration and discharge sound accompanying PD generation.

上記（ａ）のＣＣ法は、図５に示すＰＤの校正・測定回路図において、供試体ＴＦ中のＰＤによる電荷量Ｑを検出インピーダンスＺに発生する電圧Ｖｄとして捉えるもので、供試体ＴＦで電荷量ＱのＰＤが発生した場合に、検出インピーダンスＺの両端に発生する電圧Ｖｄは、供試体ＴＦの静電容量Ｃａ、結合コンデンサＣｋの静電容量、検出インピーダンスＺとその周波数特性などにより計算では求めることが出来ない。   The CC method (a) above captures the charge amount Q due to the PD in the specimen TF as the voltage Vd generated in the detection impedance Z in the PD calibration / measurement circuit diagram shown in FIG. When a PD having a charge amount Q is generated, the voltage Vd generated at both ends of the detection impedance Z is calculated from the capacitance Ca of the specimen TF, the capacitance of the coupling capacitor Ck, the detection impedance Z and its frequency characteristics, etc. Then you can not ask.

このため、図５では、既知の電荷量Ｑｃａｌを供試体ＴＦに注入して測定器ＭＩの感度調整（校正）を行うようにしている。なお、図中、Ｃｂは供試体ＴＦの欠陥部に直列に挿入される静電容量、Ｃｃは供試体ＴＦの欠陥部の静電容量である。   For this reason, in FIG. 5, a known charge amount Qcal is injected into the specimen TF to adjust the sensitivity of the measuring instrument MI (calibration). In the figure, Cb is a capacitance inserted in series with the defective portion of the specimen TF, and Cc is a capacitance of the defective portion of the specimen TF.

また、上記（ｂ）の高周波ＣＴ法は、上述の主回路の電圧から直接部分放電を測定する手法（ａ）に比較して、接地線に高周波ＣＴを取り付けるのみの非常に簡便な手法であるが、測定放電電荷量の目安とする校正が困難なことと、ＰＤ検出感度が極端に低下する（例えば、特許文献１参照。）。   The high-frequency CT method (b) is a very simple method in which the high-frequency CT is simply attached to the ground line, compared to the method (a) in which partial discharge is directly measured from the voltage of the main circuit. However, calibration as a measure of the measured discharge charge amount is difficult, and the PD detection sensitivity is extremely reduced (see, for example, Patent Document 1).

さらに、上記（ｃ）の代表例としては、一つにＡｃｏｕｓｔｉｃ Ｅｍｉｓｓｉｏｎ（以下ＡＥ法：音響法）が挙げられる。ＡＥ法は、主に圧電素子によるセンサで、金属表面などに伝わる弾性波を検出し、信号処理を行うことで、ＰＤ発生値を推測する手法である。   Furthermore, as a representative example of the above (c), one example is Acoustic Emission (hereinafter referred to as AE method: acoustic method). The AE method is a method of estimating a PD generation value by detecting an elastic wave transmitted to a metal surface or the like by a sensor mainly using a piezoelectric element and performing signal processing.

この他、圧電素子をセンサとしては、パラボラでＰＤ発生に伴い生じた超音波を直接捉える音響法や光ファイバーを渦巻き形にしたセンサもある。このうち前者の圧電素子をセンサとした手法は、集音した信号を増幅回路や各種フィルタを通してＦＦＴ演算などにより放電音を特定するものであり、後者の光ファイバーを渦巻き形にしたセンサは、ＰＤに伴う音響信号によってセンサ部に生じる伝送光の強度変化を検出するものである（例えば、特許文献２参照。）。
特開平０７−３３５４４５号公報 特開平０５−２２３８８３号公報 In addition, there are acoustic sensors that directly capture the ultrasonic waves generated by the occurrence of PD in the parabola and sensors that have a spiral optical fiber as the piezoelectric element sensor. Among them, the former method using a piezoelectric element as a sensor is to specify a discharge sound by using FFT processing or the like through amplifying circuits and various filters for a collected signal, and the latter sensor having a spiral optical fiber is used as a PD. A change in the intensity of the transmitted light generated in the sensor unit by the accompanying acoustic signal is detected (for example, see Patent Document 2).
Japanese Patent Laid-Open No. 07-335445 Japanese Patent Laid-Open No. 05-238883

上記（ａ）のＣＣ法では、測定のためには供試体に直接カップリングコンデンサを接続する必要があるとともに、試験電圧印加用の電源設備を必要とし、測定を行う度に設備や機器の停止が必要となるなどの問題がある。   In the CC method (a) above, it is necessary to connect a coupling capacitor directly to the specimen for measurement, and a power supply facility for applying the test voltage is required. There is a problem that is necessary.

上記（ｂ）の高周波ＣＴ法でのＰＤ測定は、設備の接地線に高周波ＣＴを取り付けて測定を行う構成であるが、配電盤などに収納されている各機器や部品は、基本的に共通接地されているため、ＰＤが検出された場合、その発生位置の特定が困難である。また、漏れ電流に付加されるパルス電流を測定するため、上述のＣＣ法に比べ、ＰＤ検出感度が悪い問題がある。   PD measurement by the high-frequency CT method in (b) above is a configuration in which high-frequency CT is attached to the ground wire of the equipment, but each device and part housed in a switchboard etc. is basically a common ground. Therefore, when a PD is detected, it is difficult to specify the generation position. Further, since the pulse current added to the leakage current is measured, there is a problem that the PD detection sensitivity is poor as compared with the CC method described above.

上記（ｃ）のＰＤ発生に伴う弾性波振動や放電音を音響的に検出する診断測定手法（ＡＥ法）では、運転中の放電現象による弾性波を直接もしくは間接的に検出するが、配電盤に収納された計器用変圧器（変成器）では間接的検出法として、図６に示す配電盤２１の側面壁２１ａなどにＡＥセンサ２２を取り付けて測定を行う手段がある。なお、２３は計器用変圧器（変成器）ＶＴである。   In the diagnostic measurement method (AE method) for acoustically detecting elastic wave vibration and discharge sound due to PD generation in (c) above, the elastic wave due to the discharge phenomenon during operation is detected directly or indirectly. In the stored instrument transformer (transformer), as an indirect detection method, there is a means for measuring by attaching an AE sensor 22 to the side wall 21a of the switchboard 21 shown in FIG. Reference numeral 23 denotes an instrument transformer (transformer) VT.

図６のように側壁面２１ａに取り付けたＡＥセンサ２２を用いれば、配電盤２１の内部の放電現象に伴う弾性波を検出可能である反面、内部のどの部分（あるいはどの相）で放電現象が起きているかの特定が困難である。さらに、雑音（ホワイトノイズ）の影響も大きく、ノイズの中から小さな放電現象に伴う信号を取り出すことも課題である。   If the AE sensor 22 attached to the side wall surface 21a as shown in FIG. 6 is used, the elastic wave accompanying the discharge phenomenon inside the switchboard 21 can be detected, but the discharge phenomenon occurs in any part (or which phase) inside. It is difficult to identify whether Further, the influence of noise (white noise) is large, and it is also a problem to extract a signal accompanying a small discharge phenomenon from the noise.

特に、計器用変圧器は鉄心を有しており、これを発生源とした騒音が発生しＰＤの検出精度を低下させている。騒音発生源の直接要因としては、鉄心の繋ぎ目および積層間に働く磁気力による振動と、鉄心の磁歪現象による振動が挙げられる。   In particular, an instrument transformer has an iron core, and noise is generated from the iron core to reduce the PD detection accuracy. As a direct factor of the noise generation source, there are vibration due to the magnetic force acting between the joints and laminations of the iron core and vibration due to the magnetostriction phenomenon of the iron core.

また、二次的要因としては、フレーム、鉄心締付構造や周囲条件による共振現象と、磁気力および磁歪現象による構造物振動などが挙げられる。これらの騒音が、電源電圧波形に同期して発生するため、同様に電源電圧に同期して発生するＡＥ法による部分放電測定信号に混在し、測定された信号が部分放電によるものか振動ノイズによるものかの分別が困難である。   Further, secondary factors include a resonance phenomenon caused by a frame, an iron core tightening structure, and ambient conditions, and a structure vibration caused by a magnetic force and a magnetostriction phenomenon. Since these noises are generated in synchronization with the power supply voltage waveform, they are also mixed in the partial discharge measurement signals by the AE method generated in synchronization with the power supply voltage, and the measured signals are due to partial discharges or due to vibration noises. It is difficult to separate things.

図７は、ＡＥセンサによる部分放電測定例であり、部分放電が発生していない状態でのＡＥセンサ測定信号であるが、部分放電の発生が無いにもかかわらず、周期性のある信号（部分放電信号と同周期）が検出されている。これは計器用変圧器から発せられる振動ノイズの例である。   FIG. 7 shows an example of partial discharge measurement by an AE sensor, which is an AE sensor measurement signal in a state where no partial discharge has occurred. The same period as the discharge signal) is detected. This is an example of vibration noise emitted from an instrument transformer.

また、放電現象を音響により捉える手法では、配電盤に収納されている計器用変圧器へ適用する場合、盤内に配置されたバリアなどにより測定が困難な場合があり、さらに、完全に密閉されている場合は、バリアなどの開放が必要となる。なお、この方式では、気中放電（コロナ放電）は捉えられるが、モールド内部で発生した部分放電の検出は不可能である。ＡＥ法と同様に、ノイズの中から小さな放電音を抽出することも課題である。さらに、測定結果から三相のどの相の変圧器からＰＤが発生しているかを明確に把握することが困難である。   In addition, in the method of capturing the discharge phenomenon by sound, when applied to an instrument transformer housed in a switchboard, the measurement may be difficult due to a barrier placed in the panel, etc. If it is, opening a barrier or the like is required. In this method, air discharge (corona discharge) can be detected, but partial discharge generated in the mold cannot be detected. Similar to the AE method, it is also a problem to extract a small discharge sound from noise. Furthermore, it is difficult to clearly grasp from which three-phase transformer the PD is generated from the measurement result.

この発明は、上記の事情に鑑みてなされたもので、振動ノイズをほとんど除去して、振動ノイズと部分放電発生による信号との判別を確実にし、しかも相毎の部分放電発生を明確に検出できる干渉型光ファイバーを用いたＡＥセンサ及びこのＡＥセンサによる部分放電計測装置を提供することを課題とする。   The present invention has been made in view of the above-described circumstances, and can substantially eliminate vibration noise, ensure discrimination between vibration noise and a signal due to partial discharge, and can clearly detect occurrence of partial discharge for each phase. It is an object of the present invention to provide an AE sensor using an interference type optical fiber and a partial discharge measuring device using the AE sensor.

この発明は、上記の課題を達成するために、第1発明は、開口面を有するケース本体と、このケース本体の開口面を閉塞し、ケース本体内に空間部を形成する測定面部材と、この測定面部材の空間部側に配設されるとともに、その部材に密着して設けられた反射光ファイバーと、この反射光ファイバーから一定間隔隔てた位置にケース本体を貫通して固着され、端部が空間部に望まれたハーフミラーを有する照射光ファイバーとからなり、
被計測部位に測定面部材を密接して取り付けられ、被計測部からの部分放電による超音波振動を、測定面部材、反射光ファイバーを介して空間部に伝達させて、その空間を振動させ空間部内の干渉光線の変化を、ハーフミラーを介して照射光ファイバーから取り出すようにしたことを特徴とする。 In order to achieve the above object, the present invention provides a case main body having an opening surface, a measurement surface member that closes the opening surface of the case main body and forms a space in the case main body, The measuring surface member is disposed on the space portion side and is attached in close contact with the reflecting optical fiber, and fixed at a predetermined distance from the reflecting optical fiber through the case body, and the end portion is It consists of an irradiation optical fiber having a desired half mirror in the space,
The measurement surface member is closely attached to the measurement target part, and the ultrasonic vibration due to the partial discharge from the measurement target part is transmitted to the space part via the measurement surface member and the reflective optical fiber, and the space is vibrated. The change of the interference light beam is extracted from the irradiated optical fiber through a half mirror.

第2発明は、被計測部に取り付けられた干渉型光ファイバーＡＥセンサと、このＡＥセンサに部分放電検出用の光線を送る発光素子と、ＡＥセンサが被計測部からの部分放電を干渉光線の変化として抽出し、この抽出光線を電気信号に変換する光−電気信号変換器と、この光−電気信号変換器の電気信号を増幅し、その信号の中から目的の信号を通過させるフィルタと、このフィルタを通過した目的信号を処理してディスプレイに表示する処理部とを備えたことを特徴とする。   The second invention is an interference type optical fiber AE sensor attached to a part to be measured, a light emitting element for sending a light beam for partial discharge detection to the AE sensor, and the AE sensor to change a partial discharge from the part to be measured. And an optical-electrical signal converter that converts the extracted light into an electrical signal, a filter that amplifies the electrical signal of the optical-electrical signal converter, and passes a target signal from the signal, and And a processing unit that processes a target signal that has passed through the filter and displays the target signal on a display.

以上述べたように、この発明の干渉型光ファイバーを用いたＡＥセンサによれば、センサ自体が無誘導であるため、絶縁性に関して問題はなく、センサ自体の小型化が図れるとともに、広範囲に亘って取り付けが可能となる。   As described above, according to the AE sensor using the interference type optical fiber of the present invention, since the sensor itself is non-inductive, there is no problem with insulation, and the sensor itself can be reduced in size and can be widely used. Installation is possible.

また、このＡＥセンサを用いた部分放電測定装置によれば、モールド型計器用変圧器（変成器）のモールド部へＡＥセンサを直接取り付けてＰＤ測定を行うことで、ＡＥ測定信号に、変圧器自体から発せられる振動ノイズの混入をほとんど除去できるようになり、ＡＥ法によるＰＤ検出が可能となり、計器用変圧器の異常検知と劣化状態の検出精度の向上と異常（劣化）部位の特定ができ、的確な保全（メイテナンス）が行え、電気設備全体の信頼性の向上を図ることができる。   Further, according to the partial discharge measuring apparatus using the AE sensor, the PD is measured by directly attaching the AE sensor to the mold part of the molded-type instrument transformer (transformer), so that the transformer is converted into the AE measurement signal. It is possible to remove most of the vibration noise generated from itself, enable PD detection by the AE method, improve the abnormality detection of instrument transformers, improve the detection accuracy of deterioration state, and identify the abnormality (deterioration) part. Therefore, accurate maintenance (maintenance) can be performed, and the reliability of the entire electrical equipment can be improved.

さらに、この発明によれば、モールド部へのＡＥセンサ直接取り付けに加えて、変圧器の設置用鉄枠部へもＡＥセンサを取り付けて同時にＰＤ測定を行うことで、両者の測定結果から信号強度の高い位相を比較し、変圧器自体から発せられる振動ノイズとＰＤ発生による信号の分別を更に明確に行えることが可能となったので、上記と同様に変圧器の異常検知と劣化状態の検出精度の向上と異常部位の特定ができ、的確な保全が行え、電気設備全体の信頼性の向上を図ることができる。   Further, according to the present invention, in addition to the direct attachment of the AE sensor to the mold part, the AE sensor is also attached to the iron frame part for installing the transformer and the PD measurement is performed at the same time. Compared to the high phase of the transformer, the vibration noise emitted from the transformer itself and the signal separation due to the generation of PD can be more clearly distinguished. And improvement of the reliability of the entire electrical equipment can be achieved.

この他、モールド型計器用変圧器の各相のモールド部へＡＥセンサを個別に取り付けて同時にＰＤ測定を行うことで、どの相でＰＤが発生しているかを明確に分離することが可能となるとともに、上記と同様な作用効果が得られる。   In addition, by separately attaching an AE sensor to the mold part of each phase of the molded-type instrument transformer and performing PD measurement at the same time, it becomes possible to clearly separate in which phase the PD is generated. At the same time, the same effects as described above can be obtained.

以下この発明の実施の形態を図面に基づいて説明するにあたり、まず、下記ＡＥセンサをモールド型計器用変圧器（変成器）のモールド部に直接取り付けてＰＤ検出法の検討を行ったところ、下記のような結果を得た。この結果を踏まえてＰＤ検出測定手段の実用性を考慮し、実フィールド実機への適用を試み見た。   In describing the embodiment of the present invention with reference to the drawings, first, the following AE sensor is directly attached to the mold part of a molded-type instrument transformer (transformer) and the PD detection method is examined. The result was as follows. Based on this result, we considered the practicality of the PD detection measurement means and tried to apply it to an actual field machine.

上記モールド型計器用変圧器のＰＤ検出法として、活線状態で診断を行うことができるＡＥ法の採用とＡＥセンサの取り付け位置について検討した図を図１に示す。図１に示すように、ＡＥセンサ１１ａをモールド型計器用変圧器１２のモールド部１２ａへ取り付けて実験を行った結果、下記結果１〜３が有効であることが判明した。   As a PD detection method for the above-mentioned mold-type instrument transformer, FIG. 1 is a diagram that examines the adoption of the AE method capable of performing diagnosis in a live line state and the mounting position of the AE sensor. As shown in FIG. 1, as a result of performing an experiment with the AE sensor 11a attached to the mold part 12a of the molded instrument transformer 12, the following results 1 to 3 were found to be effective.

但し、これらに共通する課題として、ＡＥセンサ１１ａの取り付け場所が、ＡＥセンサのサイズや、測定面への密着などの問題から制限されてしまう点と、ＰＺＥ素子を使用した汎用のＡＥセンサでは、センサの外装が金属であることや、測定信号の伝達に銅線を使用していることなどから、実フィールドで使用する際の絶縁性が課題となる。   However, as a problem common to these, in the general-purpose AE sensor using the PZE element, the mounting location of the AE sensor 11a is limited due to problems such as the size of the AE sensor and adhesion to the measurement surface. Since the exterior of the sensor is made of metal and copper wire is used for transmitting measurement signals, insulation when used in an actual field becomes a problem.

［結果１］
モールド型計器用変圧器１２のモールド部１２ａへＡＥセンサ１１ａを直接取り付けてＰＤ測定を実施することで、ＡＥ測定信号に、変圧器自体から発せられる振動ノイズが、ほとんど除去でき、これまで困難であったモールド型計器用変圧器のＡＥ法によるＰＤ検出が可能となった。図２にＡＥセンサによるモールド型計器用変圧器のＰＤ測定データの一例を示す。この図２の測定データからＡＥセンサ１１ａと同時に測定したカップリングコンデンサ法による測定結果に同期した信号（ＰＤ）を検出できていることが確認できる。 [Result 1]
By directly attaching the AE sensor 11a to the mold part 12a of the mold-type instrument transformer 12 and performing PD measurement, vibration noise emitted from the transformer itself can be almost eliminated from the AE measurement signal, which has been difficult until now. It was possible to detect PD by the AE method of the existing mold type instrument transformer. FIG. 2 shows an example of PD measurement data of a molded instrument transformer using an AE sensor. It can be confirmed that the signal (PD) synchronized with the measurement result by the coupling capacitor method measured simultaneously with the AE sensor 11a can be detected from the measurement data of FIG.

［結果２］
モールド型計器用変圧器１２のモールド部１２ａへのＡＥセンサ１１ａを直接取り付けたことに加え、変圧器１２の設置用鉄枠部１２ｂ（鉄心部１３と連結している部分）へもＡＥセンサ１１ｂを取り付けて同時にＰＤの測定を行うことで、両者の測定結果から信号強度の高い位相を比較し、変圧器自体から発せられる振動ノイズとＰＤ発生による信号の分別を更に明確に行えることを可能にした。 [Result 2]
In addition to directly attaching the AE sensor 11a to the mold part 12a of the molded instrument transformer 12, the AE sensor 11b is also attached to the installation iron frame part 12b (part connected to the iron core part 13). At the same time, it is possible to compare the phase of high signal intensity from the measurement results of both, and to further clearly separate the vibration noise generated from the transformer itself and the signal due to PD generation did.

［結果３］
モールド型計器用変圧器の各相（３相の場合は３個、若しくは変圧器２台の場合は２個）のモールド部１２ａへのＡＥセンサ１１ａを個別に取り付けて同時にＰＤ測定をおこなうことで、どの相（どの変圧器）でＰＤが発生しているかを明確に分離することを可能にした。 [Result 3]
By individually mounting the AE sensor 11a to the mold part 12a of each phase (three in the case of three phases, or two in the case of two transformers) of the mold-type instrument transformer and performing PD measurement simultaneously This makes it possible to clearly separate which phase (which transformer) generates PD.

上記のようなことに鑑みて、この発明の実施の形態では、モールド型計器用変圧器のＰＤ検出手段として、活線状態で診断を行うことができるＡＥ法について、干渉型光ファイバーＡＥセンサを採用した。   In view of the above, the embodiment of the present invention employs an interference type optical fiber AE sensor for the AE method capable of performing diagnosis in a live line state as the PD detection means of the molded instrument transformer. did.

この干渉型光ファイバーＡＥセンサは、検出周波数が数十ｋＨｚから数百ｋＨｚとし、診断対象機種により共振周波数が変更できるようにした。   The interference type optical fiber AE sensor has a detection frequency of several tens of kHz to several hundreds of kHz, and the resonance frequency can be changed depending on the model to be diagnosed.

図３は、干渉型光ファイバーＡＥセンサの基本構造を示すもので、図３において、樹脂製で椀型形状のケース本体３１を伏せた状態にしたそのケース本体３１の頂部を貫通させて、照射光ファイバー３２の先端部をケース本体３１の空間部３３に望ませてから前記貫通部にて照射光ファイバー３２を固着する。   FIG. 3 shows the basic structure of the interference type optical fiber AE sensor. In FIG. 3, the top part of the case body 31 made of resin and having the saddle-shaped case body 31 turned down is penetrated to irradiate the optical fiber. The irradiation optical fiber 32 is fixed at the penetration portion after the distal end portion 32 is desired in the space portion 33 of the case body 31.

一方、椀型形状のケース本体３１の開口面には、例えば、モールド型計器用変圧器のモールド部に密接して取り付ける測定面部材３４を設けて、その開口面を閉塞する。この測定面部材３４のケース本体３１の空間部３３側には、反射光ファイバー３５を密着配置させ、その反射光ファイバー３５は、空間部３３に望ませた照射光ファイバー３２の先端部から一定の間隔を隔てて配置される。なお、照射光ファイバー３２の端部の光軸には、ハーフミラー３６が配設されている。   On the other hand, on the opening surface of the bowl-shaped case body 31, for example, a measurement surface member 34 that is attached in close contact with the mold part of the molded-type instrument transformer is provided to close the opening surface. A reflective optical fiber 35 is disposed in close contact with the measurement surface member 34 on the space 33 side of the case body 31, and the reflective optical fiber 35 is spaced from the tip of the irradiation optical fiber 32 desired by the space 33. Arranged. A half mirror 36 is disposed on the optical axis at the end of the irradiation optical fiber 32.

このように構成した干渉型光ファイバーＡＥセンサのケース本体３１を、モールド型計器用変圧器のモールド部に取り付ける際に、測定面部材３４を変圧器のモールド部に密接して取り付けることにより、そのモールド部内で、ＰＤが発生したことに伴い発生する超音波(弾性波）による超音波振動が、測定面部材３４、反射光ファイバー３５を介して、ケース本体３１の空間部３３に伝達されて空間が振動し、照射光ファイバー３２からの光線に干渉の変化が生じる。この変化の度合いをＰＤとして検出する。   When the case body 31 of the interference type optical fiber AE sensor configured as described above is attached to the mold part of the molded instrument transformer, the measurement surface member 34 is attached in close contact with the mold part of the transformer so that the mold In the unit, ultrasonic vibration due to the ultrasonic wave (elastic wave) generated by the occurrence of PD is transmitted to the space part 33 of the case body 31 via the measurement surface member 34 and the reflective optical fiber 35, and the space vibrates. Then, a change in interference occurs in the light beam from the irradiation optical fiber 32. The degree of this change is detected as PD.

部分放電（ＰＤ）の同定：ＰＤは、基本的に電圧上昇時に発生する（ＰＤはパルスであり群集で発生）ため、電源電圧１周期で正負極の２回の放電（群）が発生することになる。すなわち、ＰＤ（群）は、電源周波数の２倍周期の周波数成分を持つことになる。よって、測定したＡＥ信号の包絡線検波処理後の信号をＦＦＴ変換し、電源周波数の２倍成分があるか否か、もしくはその強度によりＰＤを検出している。
［実施形態１］
モールド型計器用変圧器のモールド部へ図３に示す干渉型光ファイバーＡＥセンサを直接取り付けて、ＰＤ測定を実施することで、一般的な圧電型ＡＥセンサ同様に、ＡＥ測定信号に変圧器自体から発せられる振動ノイズの混入をほとんど除去できるからである。これは、モールド部と鉄心部とで固有インピーダンスの差が異なるため、鉄心部表面で反射し、モールド部に伝わって来ないためである。このため、これまで困難であったモールド型計器用変圧器のＡＥ法によるＰＤ検出が可能となった。
［実施形態２］
モールド型計器用変圧器のモールド部へ図３に示す干渉型光ファイバーＡＥセンサを直接取り付けに加えて、変圧器の設置用鉄枠部（鉄心部と連結している部分）へも干渉型光ファイバーＡＥセンサを取り付けて同時に測定を行うことで、一般的な圧電型のＡＥセンサ同様に、両者の測定結果から信号強度の高い位相を比較し、変圧器自体から発せられる振動ノイズとＰＤ発生による信号の分別を更に明確に行えることを可能にした。
［実施形態３］
モールド型計器用変圧器の各相（三相の場合は３個、もしくは変圧器２台の場合は２個）のモールド部あるいは鉄心部へ図３に示す干渉型光ファイバーＡＥセンサを個別に取り付けて同時にＰＤ測定を行うことで、どの相（どの変圧器）でＰＤが発生しているかを明確に分離判別することが可能になった。この干渉型光ファイバーＡＥセンサを使用したＰＤ計測システム構成図を図４に示す。 Identification of partial discharge (PD): PD is basically generated when the voltage rises (PD is a pulse and generated in a crowd), so that two discharges (group) of positive and negative electrodes occur in one cycle of the power supply voltage. become. That is, the PD (group) has a frequency component having a period twice the power supply frequency. Therefore, the signal after the envelope detection processing of the measured AE signal is subjected to FFT conversion, and the PD is detected based on whether or not there is a double component of the power supply frequency or its intensity.
[Embodiment 1]
By directly attaching the interference type optical fiber AE sensor shown in FIG. 3 to the mold part of the mold type instrument transformer and carrying out PD measurement, the AE measurement signal is transmitted from the transformer itself in the same manner as a general piezoelectric type AE sensor. This is because most of the vibration noise generated can be removed. This is because the difference in specific impedance is different between the mold part and the iron core part, so that it is reflected on the surface of the iron core part and is not transmitted to the mold part. For this reason, it has become possible to detect PD by the AE method for a mold-type instrument transformer, which has been difficult until now.
[Embodiment 2]
In addition to directly attaching the interference type optical fiber AE sensor shown in FIG. 3 to the mold part of the molded instrument transformer, the interference type optical fiber AE is also applied to the iron frame part (the part connected to the core part) for installing the transformer. By attaching a sensor and performing measurement at the same time, similar to a general piezoelectric type AE sensor, the phase of high signal intensity is compared from the measurement results of both, and vibration noise emitted from the transformer itself and the signal generated by PD generation are compared. It became possible to perform the separation more clearly.
[Embodiment 3]
The interference type optical fiber AE sensor shown in FIG. 3 is individually attached to the mold part or the iron core part of each phase (three in the case of three phases, or two in the case of two transformers) of the molded instrument transformer. By performing PD measurement at the same time, it has become possible to clearly separate and determine which phase (which transformer) generates PD. FIG. 4 shows a configuration diagram of a PD measurement system using this interference type optical fiber AE sensor.

図４において、４１ａ，４１ｂ，４１ｃは、図３に示す干渉型光ファイバーＡＥセンサ４２ａ，４２ｂ，４２ｃにカプラー４３ａ，４３ｂ，４３ｃを介してＰＤ検出用光線を送る発光ダイオードである。ＡＥセンサ４２ａ，４２ｂ，４２ｃは、安全性を考慮してモールド型計器用変圧器の変圧器鉄心部から下の部位に取り付けられる。ＡＥセンサ４２ａ，４２ｂ，４２ｃがＰＤを検出すると、この検出ＰＤは、カプラー４３ａ，４３ｂ，４３ｃを介してホトダイオード４４ａ，４４ｂ，４４ｃに供給される。   In FIG. 4, reference numerals 41a, 41b, and 41c denote light emitting diodes that send PD detection light beams to the interference type optical fiber AE sensors 42a, 42b, and 42c shown in FIG. 3 through the couplers 43a, 43b, and 43c. The AE sensors 42a, 42b and 42c are attached to the lower part from the transformer core of the molded instrument transformer in consideration of safety. When the AE sensors 42a, 42b, and 42c detect the PD, the detected PD is supplied to the photodiodes 44a, 44b, and 44c via the couplers 43a, 43b, and 43c.

ホトダイオード４４ａ，４４ｂ，４４ｃは、検出したＰＤを電気信号に変換してアンプ４５ａ，４５ｂ，４５ｃにより所定の値まで増幅し、バンドパスフィルタ４６ａ，４６ｂ，４６ｃで目的の信号を通過させた後、Ａ／Ｄ変換器４７にてデジタル信号に変換してパソコン等の処理装置４８にて処理し、ディスプレイにＰＤの状態を表示する。   The photodiodes 44a, 44b, and 44c convert the detected PD into an electric signal, amplify it to a predetermined value by the amplifiers 45a, 45b, and 45c, and pass the target signal through the band-pass filters 46a, 46b, and 46c. The digital signal is converted by the A / D converter 47 and processed by the processing device 48 such as a personal computer, and the PD state is displayed on the display.

モールド型計器用変圧器のＰＤ検出法として、活線状態で診断を行うことができるＡＥ法の採用とＡＥセンサの取り付け位置について検討した説明図。Explanatory drawing which examined adoption of AE method which can be diagnosed in a live state, and the attachment position of AE sensor as PD detection method of a mold type instrument transformer. 上記ＡＥセンサの取り付け位置におけるＰＤ測定データ。PD measurement data at the mounting position of the AE sensor. この発明の干渉型光ファイバーＡＥセンサの実施の形態を示す断面図。Sectional drawing which shows embodiment of the interference type optical fiber AE sensor of this invention. この発明の干渉型光ファイバーＡＥセンサ計測システムを示すブロック構成図。The block block diagram which shows the interference type optical fiber AE sensor measuring system of this invention. ＰＤの校正・測定回路図。PD calibration / measurement circuit diagram. ＡＥセンサによるＰＤ測定構成図。PD measurement block diagram by AE sensor. ＡＥセンサによるＰＤ測定データ。PD measurement data by AE sensor.

符号の説明Explanation of symbols

３１…椀型形状のケース本体
３２…照射光ファイバー
３３…空間部
３４…測定面部材
３５…反射光ファイバー
３６…ハーフミラー
４１ａ〜４１ｃ…発光ダイオード
４２ａ〜４２ｃ…ＡＥセンサ
４３ａ〜４３ｃ…カプラー
４４ａ〜４４ｂ…ホトダイオード
４５ａ〜４５ｂ…アンプ
４６ａ〜４６ｂ…バンドパスフィルタ
４７…Ａ／Ｄ変換器
４８…処理装置
DESCRIPTION OF SYMBOLS 31 ... Case-shaped case main body 32 ... Irradiation optical fiber 33 ... Space part 34 ... Measuring surface member 35 ... Reflective optical fiber 36 ... Half mirror 41a-41c ... Light emitting diode 42a-42c ... AE sensor 43a-43c ... Coupler 44a-44b ... Photodiodes 45a to 45b ... Amplifiers 46a to 46b ... Band pass filter 47 ... A / D converter 48 ... Processing device

Claims (2)

開口面を有するケース本体と、
このケース本体の開口面を閉塞し、ケース本体内に空間部を形成する測定面部材と、
この測定面部材の空間部側に配設されるとともに、その部材に密着して設けられた反射光ファイバーと、
この反射光ファイバーから一定間隔隔てた位置にケース本体を貫通して固着され、端部が空間部に望まれたハーフミラーを有する照射光ファイバーとからなり、
被計測部位に測定面部材を密接して取り付けられ、被計測部からの部分放電による超音波振動を、測定面部材、反射光ファイバーを介して空間部に伝達させて、その空間を振動させ空間部内の干渉光線の変化を、ハーフミラーを介して照射光ファイバーから取り出すようにしたことを特徴とする干渉型光ファイバーを用いたＡＥセンサ。 A case body having an opening surface;
A measurement surface member that closes the opening surface of the case body and forms a space in the case body;
A reflective optical fiber disposed on the space side of the measurement surface member and provided in close contact with the member;
It consists of an irradiating optical fiber having a half mirror that is fixed through the case body at a position spaced apart from this reflective optical fiber, and whose end is desired in the space,
The measurement surface member is closely attached to the measurement target part, and the ultrasonic vibration due to the partial discharge from the measurement target part is transmitted to the space part via the measurement surface member and the reflective optical fiber, and the space is vibrated. An AE sensor using an interference type optical fiber, in which the change in the interference light is extracted from the irradiated optical fiber through a half mirror. 被計測部に取り付けられた干渉型光ファイバーＡＥセンサと、
このＡＥセンサに部分放電検出用の光線を送る発光素子と、
ＡＥセンサが被計測部からの部分放電を干渉光線の変化として抽出し、この抽出光線を電気信号に変換する光−電気信号変換器と、
この光−電気信号変換器の電気信号を増幅し、その信号の中から目的の信号を通過させるフィルタと、
このフィルタを通過した目的信号を処理してディスプレイに表示する処理部とを備えたことを特徴とする干渉型光ファイバーを用いたＡＥセンサによる部分放電計測装置。
An interference type optical fiber AE sensor attached to the measurement target;
A light emitting element for sending a light for partial discharge detection to the AE sensor;
An AE sensor that extracts a partial discharge from the measurement target part as a change in the interference light beam, and converts the extracted light beam into an electrical signal;
A filter that amplifies the electrical signal of the optical-electrical signal converter and passes a target signal out of the signal;
A partial discharge measuring device using an AE sensor using an interference type optical fiber, comprising: a processing unit that processes a target signal that has passed through the filter and displays the target signal on a display.
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