JP2705266B2 - Vacuum valve switchgear - Google Patents
Vacuum valve switchgearInfo
- Publication number
- JP2705266B2 JP2705266B2 JP2051053A JP5105390A JP2705266B2 JP 2705266 B2 JP2705266 B2 JP 2705266B2 JP 2051053 A JP2051053 A JP 2051053A JP 5105390 A JP5105390 A JP 5105390A JP 2705266 B2 JP2705266 B2 JP 2705266B2
- Authority
- JP
- Japan
- Prior art keywords
- vacuum
- vacuum valve
- phase
- degree
- ground
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- High-Tension Arc-Extinguishing Switches Without Spraying Means (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 この発明は真空バルブを用いた真空遮断器，真空開閉
器等の開閉装置において、真空バルブの真空度の低下を
真空バルブ内部の異常放電を電気的に検出することによ
って検知する真空度低下検出装置に関する。DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] This invention relates to a switching device such as a vacuum circuit breaker or a vacuum switch using a vacuum valve. The present invention relates to an apparatus for detecting a degree of vacuum decrease which is detected by electrical detection.
真空遮断器，真空開閉器は他の遮断器の消弧室に相当
する部分に、高度に脱ガス，排気された完全密封形の真
空バルブが使用されている。For the vacuum circuit breaker and the vacuum switch, a completely hermetically-sealed vacuum valve that is highly degassed and evacuated is used in a portion corresponding to the arc extinguishing chamber of another circuit breaker.
真空は理想的な絶縁媒体であるが真空度が低下した場
合はその機能を発揮することができないため、真空バル
ブの信頼性が真空遮断器，真空開閉器の信頼性に対し大
きなウエイトを占めている。Vacuum is an ideal insulating medium, but its function cannot be exerted when the degree of vacuum is reduced. Therefore, the reliability of vacuum valves occupies a large weight in the reliability of vacuum circuit breakers and vacuum switches. I have.
そこで、真空バルブの製造時に高い信頼性を確保する
ため材料の選定，購入，加工精度および脱ガス処置など
製造工程の管理，および性能確認試験，検査など材料の
入手から製品出荷まで厳密な品質管理が実施されてい
る。特に真空バルブの真空度管理は最も重要であり、全
数について綿密なる管理が実施されている。Therefore, in order to ensure high reliability in the production of vacuum valves, control of the manufacturing process such as selection and purchase of materials, processing accuracy and degassing, and strict quality control from the acquisition of materials such as performance confirmation tests and inspections to product shipment Has been implemented. In particular, the control of the degree of vacuum of the vacuum valve is the most important, and careful management is performed for all the valves.
第７図は真空バルブの真空度の低下要因の原理的説明
図であり、製造時に封じられた真空バルブは10-6〜10-7
Torr程度の高真空に保持されるが、真空バルブを構成し
ている真空容器や電極，導体の内部に残存しているガス
分子がそれらの表面より徐々に放出される内部ガス放出
と、真空バルブの構成材料や接合部分のわずかな欠陥孔
より外部から空気が徐々に侵入してくるスローリークと
によって徐々に低下する。このうち、ガス放出が原因と
なるものは飽和値をもつ曲線的な変化であり、一方スロ
ーリークによるものは孔の大きさに応じた直線的な変化
である。従って、全体としての変化はこれらを重ね合わ
せたトータルガスとして示される。真空バルブの真空寿
命の管理のためには、これらの劣化要因に対して適切な
方法をとる必要がある。FIG. 7 is a view for explaining the principle of the cause of the decrease in the degree of vacuum of the vacuum valve. The vacuum valve sealed at the time of manufacture is 10 −6 to 10 −7.
The internal gas release is maintained at a high vacuum of about Torr, but the gas molecules remaining inside the vacuum vessel, electrodes, and conductors that constitute the vacuum valve are gradually released from their surfaces. And gradually decreases due to slow leaks in which air gradually penetrates from the outside through a few defective holes in the constituent materials and joints. Among them, the one caused by outgassing is a curved change having a saturation value, while the one caused by a slow leak is a linear change corresponding to the size of the hole. Therefore, the change as a whole is shown as a total gas obtained by superimposing these. In order to manage the vacuum life of the vacuum valve, it is necessary to take an appropriate method for these deterioration factors.
第８図は真空度の低下を直接検出するセンサを設けた
従来の真空バルブを示す概略断面図であり、真空バルブ
１は円筒状の絶縁容器５と、その一方端に結合された金
属製の端板4Aによって支持された固定接触子２と、絶縁
容器の他方端に結合した端板4Bおよび金属ベロー６によ
り支持された可動接触子３を主要構成要素とし、可動接
触子３を図示しない操作器によって駆動することによ
り、負荷電流または充電電流の開閉機能を有する遮断器
や開閉器が構成される。また、真空バルブ１の内部には
絶縁容器５の内側に同心状に金属シールド７が設けら
れ、電流遮断時のアークによって生じた金属蒸気が絶縁
容器５の内壁に付着して絶縁性能が低下することを防止
するよう構成される。10は真空度センサとしての例えば
マグネトロン素子であり、端板4Aに気密に取り付けられ
て真空バルブ内の真空度を検出する。ところが、この方
式は、真空バルブと真空度センサとの気密結合部に新た
なスローリークを生ずる欠点があり、真空バルブの信頼
性を損なう欠点がある。また既設の真空バルブに後加工
で真空度センサを取り付けることはほとんど不可能であ
る。FIG. 8 is a schematic sectional view showing a conventional vacuum valve provided with a sensor for directly detecting a decrease in the degree of vacuum. The vacuum valve 1 has a cylindrical insulating container 5 and a metal-made container connected to one end thereof. The fixed contact 2 supported by the end plate 4A, the end plate 4B connected to the other end of the insulating container, and the movable contact 3 supported by the metal bellows 6 are main components, and the movable contact 3 is an operation not shown. When driven by the switch, a circuit breaker or a switch having a switching function of a load current or a charging current is configured. A metal shield 7 is provided concentrically inside the insulating container 5 inside the vacuum valve 1, and metal vapor generated by an arc at the time of current interruption adheres to the inner wall of the insulating container 5, thereby deteriorating insulation performance. Is configured to prevent that. Numeral 10 denotes, for example, a magnetron element as a vacuum sensor, which is hermetically attached to the end plate 4A to detect the vacuum inside the vacuum valve. However, this method has a drawback that a new slow leak is generated at a hermetically coupled portion between the vacuum valve and the vacuum degree sensor, and has a drawback that the reliability of the vacuum valve is impaired. It is almost impossible to attach a vacuum sensor to an existing vacuum valve by post-processing.
第９図は真空バルブの内部圧力と極間の交流フラッシ
オーバ電圧との関係を示す特性線図であり、真空バルブ
内の真空度が10-3Torrオーダ程度にまで低下（悪化）す
るとフラッシオーバ電圧が低下しはじめ、10-2から10-1
Torrオーダで下限値（10-1KVオーダ）を示し、100Torr
オーダ以上ではフラッシオーバ電圧は徐々に上昇して大
気圧空気中のフラッシオーバ電圧にまで回復する。真空
バルブでは一般に真空度が10-2Torrオーダにまで低下す
ると、電力系統の常規対地電圧に耐えられなくなり、開
極状態では接触子極間または電源系統に接続された接触
子と金属シールド間に異常放電が発生し、閉極状態では
一対の接触子と金属シールドとの間に異常放電が発生す
る。そこで従来技術においても上述の特性に着目し、異
常放電を真空バルブの外部から電気的に検出することに
より、真空度の低下を間接的に検知する方式の真空度低
下の検出装置が幾つか知られている。FIG. 9 is a characteristic diagram showing the relationship between the internal pressure of the vacuum valve and the AC flashover voltage between the electrodes. When the degree of vacuum in the vacuum valve is reduced (deteriorated) to the order of 10 −3 Torr, the flashover is performed. The voltage begins to drop, from 10 -2 to 10 -1
Lower limits in Torr order indicates (10 -1 KV order), 10 0 Torr
Above the order, the flashover voltage gradually rises and recovers to the flashover voltage in atmospheric pressure air. In general, when the degree of vacuum is reduced to the order of 10 -2 Torr, the vacuum valve cannot withstand the normal ground voltage of the power system, and in the open state, between the contact poles or between the contact connected to the power supply system and the metal shield. Abnormal discharge occurs, and in the closed state, abnormal discharge occurs between the pair of contacts and the metal shield. Therefore, even in the prior art, there are some known vacuum degree decrease detection devices that detect the decrease in vacuum degree indirectly by electrically detecting abnormal discharge from outside the vacuum valve by focusing on the above-described characteristics. Have been.
第10図は第１の従来技術を示す構成図であり、交流電
力系統11と負荷系統12との間に設けられた遮断器，開閉
器等の真空バルブ１には、その負荷側に避雷器13,CR形
サージアブソーバ14等が設けられ、極間の異常放電によ
る放電電流Isが流れることに着目し、避雷器13またはサ
ージアブソーバ14の接地線側に電流センサ15を設け、開
極時に発生する放電電流を検出することにより、真空度
の低下を検知するよう構成されている。FIG. 10 is a block diagram showing the first prior art. A vacuum valve 1 such as a circuit breaker or a switch provided between an AC power system 11 and a load system 12 has a lightning arrester 13 on its load side. , CR type surge absorber 14 and the like are provided, and noticed that the abnormal discharge due to the discharge current I s between the poles flows, the current sensor 15 provided on the ground line side of the arrester 13 or surge absorber 14, generated during opening It is configured to detect a decrease in the degree of vacuum by detecting a discharge current.
第11図は第２の従来技術を示す構成図であり、真空バ
ルブ１の極間異常放電100に付随して発生する高周波ノ
イズを、真空バルブの電源系統側に高圧コンデンサ16を
介して接続された高周波ノイズの検出器17で検出するよ
う構成されている。FIG. 11 is a block diagram showing a second conventional technique, in which high-frequency noise generated accompanying the abnormal discharge 100 between the electrodes of the vacuum valve 1 is connected to the power supply system side of the vacuum valve via a high-voltage capacitor 16. The high-frequency noise detector 17 detects the high-frequency noise.
第12図は第３の従来技術を示す構成図であり、開極
時，閉極時に金属シールド７と接触子との間に発生する
異常放電101Sによって上昇する金属シールド７の電位
を、絶縁容器５を貫通して引き出された金属シールドの
外部端子7Aに高圧コンデンサ17を介して分圧コンデンサ
18を接続し、分圧コンデンサ18の電位を電圧検出器19で
測定するよう構成されている。FIG. 12 is a block diagram showing a third conventional technique, in which the potential of the metal shield 7 which rises due to the abnormal discharge 101S generated between the metal shield 7 and the contact at the time of opening and closing is determined. 5 through the high voltage capacitor 17 to the external terminal 7A of the metal shield pulled out through
18 is connected, and the potential of the voltage dividing capacitor 18 is measured by the voltage detector 19.
第13図は第４の従来技術を示す構成図であり、第３の
従来技術と同様に発生する異常放電101Sによる金属シー
ルド７の電位上昇を、絶縁容器５の外面との間に間隙を
保持して配された電位センサ20で検出するよう構成され
ている。FIG. 13 is a diagram showing the configuration of the fourth prior art, in which the potential rise of the metal shield 7 due to the abnormal discharge 101S generated in the same manner as the third prior art is maintained with a gap between the outer surface of the insulating container 5 It is configured to detect with a potential sensor 20 arranged in a row.
第１の従来技術においては、避雷器やサージアブソー
バを利用して異常放電を検出できるが、遮断時または投
入時の異常電圧によって生ずる放電電流と異常放電100
によって生ずる放電電流とを弁別するための弁別回路を
電流センサ15の出力側に設ける必要があり、検出回路が
複雑化するという問題がある。In the first prior art, an abnormal discharge can be detected using an arrester or a surge absorber.
It is necessary to provide a discriminating circuit for discriminating a discharge current generated by the current sensor 15 on the output side of the current sensor 15, and there is a problem that the detection circuit is complicated.
第２の従来技術では、極間で異常放電が発生すると直
ちにアーク放電に移行してしまうことが実験的に検証さ
れており、極間のアークドロップが小さいために、検出
される高周波ノイズの電荷量が数PCと極めて小さく、信
頼性の高い検出ができにくいという問題があり、かつ高
周波ノイズ検出用の高圧コンデンサ16を真空バルブごと
に設ける必要があり装置が大型化するという問題があ
る。In the second prior art, it has been experimentally verified that the transition to arc discharge immediately occurs when an abnormal discharge occurs between the poles. Since the arc drop between the poles is small, the charge of the detected high-frequency noise is small. There is a problem that the amount is extremely small at several PCs, and it is difficult to perform highly reliable detection. In addition, it is necessary to provide a high-voltage capacitor 16 for high-frequency noise detection for each vacuum valve, and there is a problem that the device becomes large.
また、第３の従来技術は第２の従来技術と同様に高圧
コンデンサ16を必要とし、かつ絶縁容器を貫通して外部
端子を設けなければならず、真空度の維持性能に悪影響
を及ぼす危険性がある。Further, the third prior art requires the high-voltage capacitor 16 as in the second prior art, and the external terminals must be provided through the insulating container, which may adversely affect the performance of maintaining the degree of vacuum. There is.
第４の従来技術では、金属シールドと電位センサとの
結合キャパシタンスが小さいために、他相の真空バルブ
等との間に静電容量結合が生じやすく、検出結果の判定
精度が低く、誤判定を犯しやすい欠点がある。In the fourth prior art, since the coupling capacitance between the metal shield and the potential sensor is small, capacitance coupling is easily generated between the metal shield and the other phase vacuum valve or the like. There are drawbacks that are easy to commit.
この発明の目的は、真空バルブの真空度の低下によっ
て発生する異常放電を高圧コンデンサを用いず、かつ精
度よく検出でき、したがって構成が簡素で小型な真空度
の低下検出装置を得ることにある。SUMMARY OF THE INVENTION It is an object of the present invention to provide a small-sized vacuum-drop detection device which can detect abnormal discharge caused by a reduction in the vacuum of a vacuum valve without using a high-voltage capacitor and can accurately detect the abnormal discharge.
上記課題を解決するために、この発明によれば、三相
交流電力系統に接続された真空バルブ形開閉装置の負荷
側が電力ケーブルを介して負荷回路に接続され、真空バ
ルブの真空度の低下を真空バルブ内の極間異常放電を電
気的に検出することによって検知するものであって、前
記電力ケーブルの接地導電層の接地線側に各相共通に設
けられた零相変流器からなり、前記極間異常放電により
前記電力ケーブルに流れる対地充電電流を零相電流とし
て検出するものとする。In order to solve the above problems, according to the present invention, the load side of a vacuum valve type switchgear connected to a three-phase AC power system is connected to a load circuit via a power cable, and the degree of vacuum of the vacuum valve is reduced. It is to detect abnormal discharge between the poles in the vacuum valve by electrically detecting, and comprises a zero-phase current transformer provided in common for each phase on the ground wire side of the ground conductive layer of the power cable, The charging current to the ground flowing through the power cable due to the abnormal discharge between the poles is detected as a zero-phase current.
上記手段において、真空バルブ形三相遮断器または開
閉器負荷側の電力ケーブルの接地線側に各相共通に零相
変流器を設けたことにより、真空バルブが閉状態では零
相対地充電電流は三相平衡して零になるが、開状態で異
常放電がいずれか１相または２相で発生した場合には、
負荷側の電力ケーブルの電位は異常放電を生じた相はも
とより、非接地状態の負荷を介して他相の電力ケーブル
の電位も上昇するので、零相対地充電電流も増大し、零
相変流器によって異常放電を精度よく検出できる。した
がって、高圧コンデンサの機能を電力ケーブルが兼ねる
ことによって構成が簡素化，かつ小型化された装置によ
って真空バルブの真空度の低下を精度よく検出すること
ができる。In the above means, a zero-phase-sequence current transformer is provided in common for each phase on the ground line side of the power cable on the vacuum valve type three-phase circuit breaker or the switch load side. Becomes three-phase equilibrium and becomes zero, but if abnormal discharge occurs in one or two phases in the open state,
The potential of the power cable on the load side rises not only in the phase in which abnormal discharge has occurred, but also in the power cable of the other phase via the load in the ungrounded state, so that the zero relative ground charging current increases and the zero-phase current The abnormal discharge can be accurately detected by the detector. Therefore, a reduction in the degree of vacuum of the vacuum valve can be accurately detected by a device whose structure is simplified and miniaturized by the function of the power cable also serving as the high-voltage capacitor.
以下この発明を実施例に基づいて説明する。第１図は
この発明の実施例になる真空バルブ形開閉装置の真空度
低下検出装置を示す接続図である。図において、開閉装
置としての三相遮断器21は、各相真空バルブ1U,1V,1Wが
電力ケーブル22U,22V,22Wを介して三相交流電力系統11
に接続されており、またその負荷側は電力ケーブル23U,
23V,23Wを介して非接地の負荷回路12に接続される。ま
た、真空度低下検出装置は負荷側電力ケーブル23U,23V,
23Wの対地静電容量を対地充電電流検出用の高圧コンデ
ンサに兼用し、かつ電力ケーブルの接地導電層から引き
出された各相接地線24U,24V,24Wの一括部分24に零相変
流器25を設けることによって構成される。Hereinafter, the present invention will be described based on examples. FIG. 1 is a connection diagram showing an apparatus for detecting a decrease in the degree of vacuum of a vacuum valve type opening / closing apparatus according to an embodiment of the present invention. In the figure, a three-phase circuit breaker 21 as a switching device includes a three-phase AC power system 11 in which each phase vacuum valve 1U, 1V, 1W is connected via a power cable 22U, 22V, 22W.
And the load side of the power cable 23U,
Connected to a non-grounded load circuit 12 via 23V, 23W. In addition, the vacuum degree drop detection device is a load side power cable 23U, 23V,
The 23 W ground capacitance is also used as the high voltage capacitor for detecting the ground charging current, and the zero phase current transformer is connected to the collective part 24 of each phase ground wire 24 U, 24 V, 24 W drawn from the ground conductive layer of the power cable. It is constituted by providing 25.
第２図および第３図は実施例における電力ケーブルの
概略断面図であり、電力ケーブル23は第２図に示すよう
に、各相ケーブル23U,23V,23Wがそれぞれの中心導体23A
の絶縁被覆23Bの外側に接地導電層23Cおよびその絶縁シ
ース23Dを備えたものであってよく、また第３図に示す
ように各相ケーブル23U,23V,23Wの外周を包囲する共通
の接地導電層23Eおよび絶縁シース23Fを有するものであ
ってもよく、各相共通の接地線24を一次導体とする例え
ば貫通形の零相変流器25が設けられる。また、零相変流
器25は接地線24U,24V,24Wそれぞれに設けられた変流器
をその二次巻線側で三相結線したものであってもよい。FIGS. 2 and 3 are schematic sectional views of the power cable in the embodiment. As shown in FIG. 2, the power cable 23 has a phase conductor 23A, 23V, and 23W connected to a central conductor 23A.
May be provided with a ground conductive layer 23C and an insulating sheath 23D on the outside of the insulating coating 23B, and as shown in FIG. 3, a common ground conductive layer surrounding the outer circumference of each phase cable 23U, 23V, 23W. It may have a layer 23E and an insulating sheath 23F. For example, a through-type zero-phase current transformer 25 having a common ground wire 24 for each phase as a primary conductor is provided. Further, the zero-phase current transformer 25 may be a three-phase current transformer provided on each of the ground wires 24U, 24V, 24W on the secondary winding side.
上述のように構成された真空度低下検出装置におい
て、三相遮断器21が開極状態で、かつ各真空バルブ1U,1
V,1Wの真空度が10-4Torr以下に保持された状態では、極
間の耐電圧は常規対地電圧に対して十分高い耐電圧性能
を保持するので、負荷側には電圧が発生せず、したがっ
て電力ケーブル23の対地充電電流は各相とも零になる。
また、この状態で遮断器21を閉路して負荷12に三相交流
電力が供給された状態では、各相電力ケーブルに互いに
電気角２π/3ラジアン位相がずれた対地充電電流が流れ
るが、共通の接地線24では各相対地充電電流がベクトル
合成されてその合成値Icが零となるので、零相変流器25
の検出電流は零となる。一方、各相真空バルブの一つ，
例えば23Uの真空度が10-2Torrオーダにまで低下してそ
の極間フラッシオーバ電圧が常規対地電圧を大幅に下廻
る値にまで低下すると、真空バルブ23U内の極間で異常
放電100が発生し、負荷側の電力ケーブル23Uに電源側の
電圧が印加されるとともに、非接地の三相負荷12を介し
て残る電力ケーブル23V,23Wにも電力ケーブル23Uと同相
同電位の電圧が印加される。したがって、各相電力ケー
ブル23U,23V,23Wにはそれぞれ対地充電電流が流れ、共
通の接地線24を一次導体とする零相変流器25には電力ケ
ーブル23Uの対地充電電流のほぼ３倍に相応する電流Ic
が検出される。したがって、真空バルブ23Uの極間異常
放電を適確に検出することが可能になり、真空バルブ23
Uの真空度の低下を検知することができる。In the vacuum degree decrease detection device configured as described above, the three-phase circuit breaker 21 is in the open state, and each of the vacuum valves 1U, 1
In a state where the degree of vacuum of V, 1 W is maintained at 10 -4 Torr or less, the withstand voltage between the electrodes maintains a sufficiently high withstand voltage performance with respect to the normal ground voltage, so that no voltage is generated on the load side. Therefore, the charging current to the ground of the power cable 23 becomes zero in each phase.
In this state, in the state where the circuit breaker 21 is closed and three-phase AC power is supplied to the load 12, a ground charging current having an electrical angle of 2π / 3 radian shifted from each other flows through each phase power cable. since the combined value I c at ground line 24 each relative locations charging current is the vector synthesis is zero, zero-phase current transformer 25
Is zero. On the other hand, one of the vacuum valves of each phase,
For example, when the vacuum degree of 23U drops to the order of 10 -2 Torr and the flashover voltage between the electrodes drops to a value that is much lower than the normal earth voltage, abnormal discharge 100 occurs between the electrodes in the vacuum valve 23U. Then, the voltage on the power supply side is applied to the power cable 23U on the load side, and the voltage of the same homologous potential as the power cable 23U is also applied to the remaining power cables 23V and 23W via the ungrounded three-phase load 12. . Therefore, the charging current to the ground flows in each phase power cable 23U, 23V, 23W, and the zero-phase current transformer 25 having the common grounding wire 24 as the primary conductor has almost three times the charging current to the ground of the power cable 23U. Corresponding current I c
Is detected. Therefore, abnormal discharge between the electrodes of the vacuum valve 23U can be accurately detected, and the vacuum valve 23
A decrease in the degree of vacuum of U can be detected.
また、真空バルブ２相分の真空度が同時に低下した場
合、三相負荷12には異常放電による放電電流によって２
相分の電力が供給されることになり、各相ケーブル23U,
23V,23Wに印加される電圧の瞬時値が相互に異なること
になり、零相変流器25は零相不平衡分を検出する。した
がって、２相分の真空バルブの真空度が同時に低下した
場合にもこれを検出することが可能であり、零相変流器
25の検出電流の大きさを判断部26で弁別するよう構成す
れば、異常放電が１相の真空バルブで発生したものか,2
相分の真空バルブで発生したものであるかを弁別するこ
とも可能になる。Further, when the degree of vacuum for the two phases of the vacuum valve is simultaneously reduced, the three-phase load 12 is charged by the discharge current due to the abnormal discharge.
The power for each phase will be supplied, and each phase cable 23U,
The instantaneous values of the voltages applied to 23V and 23W are different from each other, and the zero-phase current transformer 25 detects the zero-phase imbalance. Therefore, even when the degree of vacuum of the two-phase vacuum valve is reduced simultaneously, it is possible to detect this, and the zero-phase current transformer can be detected.
If the determination unit 26 is configured to discriminate the magnitude of the detected current of 25, whether the abnormal discharge has occurred in the one-phase vacuum valve, 2
It is also possible to discriminate whether or not it is generated by the vacuum valve for each phase.
第４図および第５図はこの発明の参考例を示す真空度
低下検出装置を含む真空バルブの断面図であり、第４図
は閉極状態を，第５図は開極状態を示したものである。
第４図において、真空バルブ31の円筒状の絶縁容器５の
内側には、一対の接触子２および３を間隙l2を保持して
包囲する金属シールド７が設けられ、絶縁容器５の外周
面には金属シールド７に対向するよう円筒状に形成され
た外部電極32が設けられ、外部電極32は分圧コンデンサ
33を介して接地され、分圧コンデンサ33の端子電圧Vsは
図示しない電位計により検出される。絶縁容器５は比誘
電率５ないし７程度の絶縁材で構成されるので、金属シ
ールド７と接触子２および３との間の静電容量C1は、金
属シールドと外部電極32との間の静電容量C2に較べて小
さく、かつ分圧コンデンサ33の静電容量CsはC1＜C2≪Cs
なる条件を満足する大きさに設定される。したがって、
定常運転時には三相交流電力系統11の対地電圧Vgは、各
相真空バルブそれぞれに、直列静電容量C1，C2，Csに逆
比例する形で静電容量分圧されるので、分圧コンデンサ
33の端子電圧Vsは微小な電圧値となる。一方真空バルブ
31の真空度が10-2Torrオーダにまで低下すると、一対の
接触子２および３と金属シールド７との間で異常放電10
1Sが発生し、金属シールド７の電位が電源系統の常規対
地電圧Vgに上昇し、この電位Vgを静電容量C2およびCsで
静電容量分圧することになる。したがって分圧コンデン
サ33の端子電圧Vsは上昇するので、この電位上昇を電位
計によって検出することによって異常放電の発生を検出
でき、真空度が低下した真空バルブを容易に検知するこ
とができる。FIGS. 4 and 5 are cross-sectional views of a vacuum valve including a vacuum-drop detector according to a reference example of the present invention. FIG. 4 shows a closed state, and FIG. 5 shows an open state. It is.
In FIG. 4, a metal shield 7 surrounding the pair of contacts 2 and 3 while holding a gap l 2 is provided inside the cylindrical insulating container 5 of the vacuum valve 31. Is provided with an external electrode 32 formed in a cylindrical shape so as to face the metal shield 7, and the external electrode 32 is a voltage dividing capacitor.
33 through the grounded terminal voltage V s of the dividing capacitors 33 is detected by the electrometer (not shown). Since the insulating container 5 is made of an insulating material having a relative dielectric constant of about 5 to 7, the capacitance C 1 between the metal shield 7 and the contacts 2 and 3 is set between the metal shield and the external electrode 32. The capacitance C s of the voltage dividing capacitor 33 is smaller than the capacitance C 2 , and C 1 <C 2 ≪C s
The size is set to satisfy the following condition. Therefore,
At the time of steady operation, the ground voltage V g of the three-phase AC power system 11 is divided into capacitances in each of the vacuum valves in a form inversely proportional to the series capacitances C 1 , C 2 , and C s . Voltage dividing capacitor
33 terminal voltage V s of is the small voltage value. Hand vacuum valve
When the degree of vacuum of 31 drops to the order of 10 -2 Torr, abnormal discharge 10 between the pair of contacts 2 and 3 and the metal shield 7
1S is generated, the potential of the metallic shield 7 is raised to normal regulations ground voltage V g of the power supply system, so that the pressure electrostatic capacity of the electric potential V g by the electrostatic capacitance C 2 and C s. Hence the terminal voltage V s of the dividing capacitors 33 is increased, the potential rise can detect the occurrence of abnormal discharge by detecting the electrometer, the degree of vacuum can be easily detected the vacuum valve was reduced.
真空バルブ31が第５図に示す開極状態の場合、負荷側
の接触子３はほぼ零電位となるが、真空度が低下した場
合の異常放電は極間寸法1に較べて大きいギャップ長l
2を有する金属シールド７側に放電しやすい性質を有す
るので、閉極状態におけると同様に異常放電を検出する
ことができる。なお、外部電極32は充電電流が流れるだ
けなので、絶縁容器５の外周面に沿面絶縁距離を残した
所定の幅で導電性塗膜または箔状電極を被着することに
よって容易に形成でき、ことに真空バルブ31をSF6ガス
雰囲気中に配設することによってより外部絶縁の信頼性
の高い真空度低下検出装置が得られる。When the vacuum valve 31 is in the open state shown in FIG. 5, the contact 3 on the load side has almost zero potential. However, when the degree of vacuum is reduced, abnormal discharge occurs when the gap length l is larger than the inter-electrode dimension 1.
Since it has the property of easily discharging to the side of the metal shield 7 having 2 , the abnormal discharge can be detected as in the closed state. Since only the charging current flows through the outer electrode 32, the outer electrode 32 can be easily formed by applying a conductive coating or a foil-like electrode with a predetermined width leaving a creeping insulation distance on the outer peripheral surface of the insulating container 5. By arranging the vacuum valve 31 in the SF 6 gas atmosphere, a more reliable external insulation vacuum drop detector can be obtained.
第６図はこの発明の異なる参考例を示す要部の断面図
であり、真空バルブ41がその絶縁容器35に埋設された埋
込形外部電極42を備え、分圧コンデンサを接続するため
の外部端子42Aのみが絶縁容器35の外側に露出するよう
構成された点が前述の参考例と異なっており、一対の端
板4A,4Bに対して十分な沿面絶縁距離を確保できるの
で、外部絶縁の信頼性のより優れた真空バルブとその真
空度低下検出装置が得られる。FIG. 6 is a cross-sectional view of a main part showing a different embodiment of the present invention, in which a vacuum valve 41 is provided with an embedded external electrode 42 embedded in an insulating container 35, and an external electrode for connecting a voltage dividing capacitor. The point that only the terminal 42A is configured to be exposed to the outside of the insulating container 35 is different from the above-described reference example.Since a sufficient creepage insulation distance can be secured for the pair of end plates 4A and 4B, the external insulation A highly reliable vacuum valve and a device for detecting a decrease in vacuum degree can be obtained.
この発明は前述のように、真空バルブを用いた遮断
器，開閉器等の開閉装置の負荷側電力ケーブルの対地静
電容量を充電電流検出用の高圧コンデンサに兼用してそ
の接地線側に零相変流器を配し、真空バルブの真空度が
低下することによって生ずる真空バルブ内の異常放電を
零相対地充電電流の増加によって検出するよう構成し
た。その結果、従来技術で必要とした高圧コンデンサの
機能を電力ケーブルが兼ねることによって高圧コンデン
サが不要になり、装置の構成を簡素化できるとともに、
異常放電によって生ずる零相対地充電電流の変化が大き
く、かつ定常運転時および三相同時開閉時には零相分が
ほとんど零になるので異常放電の検出感度が従来技術の
それに比べて高く、したがって簡素な構成の真空度低下
検出装置によって真空度低下を精度よく検出できる利点
が得られる。As described above, according to the present invention, the ground capacitance of the load-side power cable of a switch such as a circuit breaker or a switch using a vacuum valve is also used as a high-voltage capacitor for detecting a charging current, and is set to zero on its ground line side. A phase current transformer is provided to detect an abnormal discharge in the vacuum valve caused by a decrease in the degree of vacuum of the vacuum valve by increasing the zero relative ground charge current. As a result, the power cable also functions as the high-voltage capacitor required in the conventional technology, eliminating the need for a high-voltage capacitor, simplifying the configuration of the device,
Since the change in the zero relative ground charging current caused by abnormal discharge is large, and the zero phase component is almost zero during steady operation and three-phase simultaneous switching, the detection sensitivity of abnormal discharge is higher than that of the prior art, and therefore simpler. The advantage of being able to accurately detect the degree of vacuum decrease by the vacuum degree decrease detection device having the configuration is obtained.
第１図はこの発明の実施例になる真空バルブ形開閉装置
の真空度低下検出装置を示す接続図、第２図および第３
図は実施例における電力ケーブルの互いに異なる構成を
示す断面図、第４図および第５図はこの発明の参考例を
示す閉極状態および開極状態における断面図、第６図は
この発明の異なる参考例を示す要部の断面図、第７図は
真空バルブの真空度の経年変化を示す原理的説明図、第
８図は真空度センサを備えた従来の真空バルブを示す概
略断面図、第９図は真空バルブの真空度対極間フラッシ
オーバ特性線図、第10図は第１の従来技術を示す構成
図、第11図は第２の従来技術を示す構成図、第12図は第
３の従来技術を示す構成図、第13図は第４の従来技術を
示す構成図である。 1,31,41:真空バルブ、2,3:接触子、4:端板、5,35:絶縁
容器、7:金属シールド、10:真空度センサ、11:電源系
統、12:負荷系統、16:高圧コンデンサ、18,33:分圧コン
デンサ、21:開閉装置（三相遮断器）、1U,1V,1W:各相真
空バルブ、22,23:電力ケーブル、23C,23E:接地導電層、
24:接地線、25:零相変流器、32:外部電極、42:埋込形外
部電極、100:極間異常放電、101S:金属シールドへの異
常放電、Ic：零相対地充電電流。FIG. 1 is a connection diagram showing an apparatus for detecting a decrease in the degree of vacuum of a vacuum valve type opening / closing device according to an embodiment of the present invention, FIG. 2 and FIG.
Figures are cross-sectional views showing different configurations of the power cable in the embodiment, FIGS. 4 and 5 are cross-sectional views in a closed state and an open state showing a reference example of the present invention, and FIG. FIG. 7 is a principle explanatory view showing the secular change of the degree of vacuum of a vacuum valve, FIG. 8 is a schematic sectional view showing a conventional vacuum valve provided with a vacuum degree sensor, FIG. 9 is a diagram showing the vacuum degree versus the flashover characteristic between the electrodes of the vacuum valve, FIG. 10 is a diagram showing the first prior art, FIG. 11 is a diagram showing the second prior art, and FIG. FIG. 13 is a block diagram showing a fourth conventional technique. 1,31,41: Vacuum valve, 2,3: Contact, 4: End plate, 5,35: Insulated container, 7: Metal shield, 10: Vacuum sensor, 11: Power system, 12: Load system, 16 : High voltage condenser, 18, 33: Voltage dividing condenser, 21: Switchgear (three-phase circuit breaker), 1U, 1V, 1W: Vacuum valve for each phase, 22, 23: Power cable, 23C, 23E: Ground conductive layer,
24: ground line, 25: ZCT, 32: External electrode 42: Flush type external electrode, 100: machining gap abnormal discharge, 101S: abnormal discharge to the metal shield, I c: zero-phase-to-ground charging current .
フロントページの続き (72)発明者 柴田 和郎 神奈川県川崎市川崎区田辺新田１番１号 富士電機株式会社内 (72)発明者 鈴木 伸夫 神奈川県川崎市川崎区田辺新田１番１号 富士電機株式会社内 (56)参考文献 特開 昭62−93822（ＪＰ，Ａ) 特開 昭64−76630（ＪＰ，Ａ) 特開 昭54−103571（ＪＰ，Ａ)Continuation of the front page (72) Inventor Kazuo Shibata 1-1, Tanabe Nitta, Kawasaki-ku, Kawasaki, Kanagawa Prefecture Inside Fuji Electric Co., Ltd. (72) Inventor Nobuo Suzuki 1-1-1, Tanabe Nitta, Kawasaki-ku, Kawasaki, Kawasaki, Kanagawa Fuji (56) References JP-A-62-93822 (JP, A) JP-A-64-76630 (JP, A) JP-A-54-103571 (JP, A)
Claims (1)
形開閉装置の負荷側が電力ケーブルを介して負荷回路に
接続され、真空バルブの真空度の低下を真空バルブ内の
極間異常放電を電気的に検出することによって検知する
ものであって、前記電力ケーブルの接地導電層の接地線
側に各相共通に設けられた零相変流器からなり、前記極
間異常放電により前記電力ケーブルに流れる対地充電電
流を零相電流として検出することを特徴とする真空バル
ブ形開閉装置の真空度低下検出装置。A load side of a vacuum valve type switchgear connected to a three-phase AC power system is connected to a load circuit via a power cable to reduce a degree of vacuum of the vacuum valve and to detect abnormal discharge between poles in the vacuum valve. The power cable includes a zero-phase current transformer provided in common to each phase on a ground wire side of a ground conductive layer of the power cable. And detecting a charging current flowing to the ground as a zero-phase current.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2051053A JP2705266B2 (en) | 1989-10-04 | 1990-03-02 | Vacuum valve switchgear |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1-259350 | 1989-10-04 | ||
| JP25935089 | 1989-10-04 | ||
| JP2051053A JP2705266B2 (en) | 1989-10-04 | 1990-03-02 | Vacuum valve switchgear |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9175071A Division JP2885233B2 (en) | 1989-10-04 | 1997-07-01 | Vacuum drop detector for vacuum valve type switchgear |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03205716A JPH03205716A (en) | 1991-09-09 |
| JP2705266B2 true JP2705266B2 (en) | 1998-01-28 |
Family
ID=26391571
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2051053A Expired - Fee Related JP2705266B2 (en) | 1989-10-04 | 1990-03-02 | Vacuum valve switchgear |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2705266B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4686555B2 (en) * | 2008-01-09 | 2011-05-25 | 株式会社日立製作所 | Vacuum switchgear |
| JP5235620B2 (en) * | 2008-11-14 | 2013-07-10 | 株式会社日立製作所 | Vacuum switchgear |
| DE102013112584B4 (en) * | 2013-11-15 | 2017-12-14 | Maschinenfabrik Reinhausen Gmbh | Method and device for monitoring capacitor feedthroughs for a three-phase AC mains |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54103571A (en) * | 1978-01-31 | 1979-08-15 | Meidensha Electric Mfg Co Ltd | Vacuum level drop detection method of full solid insulated vacuum breaker |
| JPS6293822A (en) * | 1985-10-21 | 1987-04-30 | 富士電機株式会社 | Fault detector of vacuum switch |
| JPS6476630A (en) * | 1987-09-17 | 1989-03-22 | Toshiba Corp | Defective vacuum detecting device for vacuum valve |
-
1990
- 1990-03-02 JP JP2051053A patent/JP2705266B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03205716A (en) | 1991-09-09 |
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