EP0927445B1 - Electrical apparatus, particularly a surge arrester and a display system for the state of the apparatus in a central evaluation device - Google Patents

Description

TECHNICAL AREA

The invention is based on an electrical apparatus according to the Preamble of claim 1.

Electrical devices, such as surge arresters in particular, are during their often used for many years in high voltage systems and Medium voltage fields are subject to high loads. Therefore, such Apparatus often devices for indicating a faulty condition, such as one fault current flowing through the apparatus. An observer can then spot recognize the faulty condition of the apparatus without the use of aids and arrange for its replacement in good time.

Signals about the faulty condition or about any one The operating state of the apparatus is often connected to an optical fiber if necessary, several kilometers from the machine in a control room horizontal evaluation device and checked there.

STATE OF THE ART

The invention relates to a prior art of electrical apparatus, as described in Patent Abstracts of Japan, vol. 095, no. 002, March 31, 1995 & JP-A-06 325 909 A. A surge arrester described in this prior art contains a holding part in thermal contact with a body of the surge arrester made of a memory alloy and a spring-loaded one mounted on the holding part Actuating rod and one connected to a measuring device Optical fiber. The body of the surge arrester heats up impermissibly high temperatures, the holding part is deformed and gives the Operating rod free. The actuating rod interrupts the optical fiber, which indicates at the location of the measuring device that the surge arrester works incorrectly.

A medium or high voltage switching device described in EP-0 338 374 A2 has a variety of sensors based on what information is important about a switching device record the relevant physical quantities and send them to an optical fiber direct central evaluation device. Such information concerns, for example the continuous measurement of the size and voltage of the in the switching device conducted current or the density, pressure and temperature of an im Switching device of existing extinguishing gas. This information can also Position or the speed of those that can be brought into or out of engagement with one another Switch contacts or a break for the movement of the switch contacts required drive linkage include. For this purpose, sensors are preferred Position indicators, such as reflection light barriers or inductive proximity switches, intended.

The information supplied to the central evaluation device is used for one Self-diagnosis of the switching device and allow in addition to constant control of the operating status also early detection of irregularities of the Switching device.

DE-195 06 307 A1 describes a device for displaying the faulty state described a surge arrester. This device has one Switching element on which, when a fault current occurs, the two parts of a two-part metal housing carrying a display element Visualization of the display element and the formation of a fault current accepting galvanic connection moves against each other.

This device can only on site in a plant, but not from one central evaluation device can be monitored.

SUMMARY OF THE INVENTION

The object of the invention is to achieve this to create an electrical apparatus of the type mentioned at the beginning, which not only expresses a faulty state which is expressed in a fault current reports to a central evaluation device, but rather this fault current switches off at the same time and then identified in a simple and safe manner, can be removed and replaced.

This object is achieved by an electrical apparatus, according to Claim 1.

The electrical apparatus according to the invention is characterized in that the The fault current has already been reported in the central evaluation device interrupted and the defective apparatus by forming an optical Display element is marked. The faulty apparatus can then go on site be identified quickly. Because the optical fiber can be plugged into this device connected, the apparatus can be removed quickly and by an error-free one Apparatus to be replaced.

In an extremely advantageous manner, the electrical apparatus according to the invention in Cable run of the optical waveguide in series with at least one other a portion of the optical fiber as a sensor-containing electrical apparatus connected. It can then be identified with only one optical fiber in the control room become faulty in a group of electrical apparatuses is working. Is the moving part of each of the electrical devices with one Display element equipped, so it can be easily determined on site which one Device from the group of devices is malfunctioning. These are preferably electrical apparatus one phase of a multi-phase power network assigned, d. H. locally closely adjacent in a plant or in a field arranged. Such a system for displaying the state of an electrical Devices in a control room located away from the device can also be used Realize extremely simple means, can easily in retrospect existing high or medium voltage systems or fields are installed and is also characterized by great reliability.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig.1

eine dreiphasige Hochspannungsleitung, bei der jeder Leiter mit einem als Überspannungsableiter ausgeführten elektrischen Apparat nach der Erfindung elektrisch leitend verbunden ist und der Zustand dieser Apparate über einen Lichtwellenleiter in einer von der Leitung entfernt angeordneten zentralen Auswertevorrichtung überprüft wird,

Fig.2

eine Aufsicht auf einen axial geführten Schnitt durch eine im wesentlichen zylindersymmetrisch ausgebildete und in einen Stromanschluss eines der Überspannungsableiter gemäss Fig.1 eingebaute Anzeigevorrichtung mit einem als Abschnitt des Lichtwellenleiters ausgebildeten und beim Auftreten eines Fehlerstroms durch ein bewegliches Teil der Anzeigevorrichtung zerstörbaren Sensor vor dem Ansprechen,

Fig.3

die Anzeigevorrichtung gemäss Fig.2 nach dem Ansprechen,

Fig.4

eine geringfügig abgeänderte Ausführungsform der Anzeigevorrichtung gemäss Fig.2 vor dem Ansprechen, und

Fig.5

die Anzeigevorrichtung gemäss Fig.4 nach dem Ansprechen.

Preferred exemplary embodiments of the invention and the further advantages achievable therewith are explained in more detail below with reference to drawings. Here shows:

Fig.1

a three-phase high-voltage line, in which each conductor is electrically conductively connected to an electrical apparatus designed as a surge arrester according to the invention, and the state of these apparatuses is checked via an optical waveguide in a central evaluation device arranged away from the line,

Fig.2

1 shows a top view of an axially guided section through an essentially cylindrical-symmetrical design and built into a power connection of one of the surge arresters according to FIG. 1 with a sensor designed as a section of the optical waveguide and which can be destroyed if a fault current occurs through a movable part of the display device before the response,

Figure 3

the display device according to Figure 2 after the response,

Figure 4

a slightly modified embodiment of the display device according to Figure 2 before the response, and

Figure 5

the display device according to Figure 4 after the response.

WAY OF CARRYING OUT THE INVENTION

In all figures, the same reference symbols also designate parts with the same effect. In FIG. 1, TR denotes a transformer which feeds high voltage into a three-phase high-voltage line having three conductors R, S, T. One of three surge arresters A _R , A _S , A _{T is} suspended from each of the three phase conductors R, S, T. The surge arresters are each electrically connected to one of the phase conductors R, S, T by one of two power connections and are each fastened to a grounded holder G designed as a scaffold using a support insulator I. The second of the two current connections of each of the surge arresters A _R , A _S , A _T is electrically connected to the grounded holder G via a grounding cable E.

An optical waveguide L is guided by a central evaluation device AW through the surge arrester A _T A _S and pass to the surge arrester A _R. The evaluation device AW is housed in a control room typically up to several kilometers away from the surge arresters and contains a light source LQ, for example a laser diode, which continuously feeds a light signal into the optical waveguide L during operation of the surge arresters, and a light signal which detects the fed-in light signal after passing through the surge arresters Receiver FW, for example a photo resistor. The receiver acts on a warning element containing, for example, a green and a red control lamp KG and KR.

The optical waveguide L can be in the form of a loop, one end with the light source LQ and the other end is in active connection with the receiver FW. The conductor L can but also in the form of a stub, one of which End is in operative connection with the light source LQ, and their other end is finished with a reflector.

Each of the surge arresters contains a sensor designed as a section LA of the optical waveguide L. This sensor is in each case part of a device 3 provided in each of the surge arresters, with which a faulty state of the associated surge arrester, for example a fault current flowing through the surge arrester, can be made optically visible on site. The surge arrester A _{R which is} furthest away in the series connection of the surge arresters from the central evaluation device AW can contain a reflection light barrier fed by the light source LQ via the optical waveguide L and fed via the optical waveguide L into the receiver FW instead of an optical waveguide section LA.

FIGS. 2 to 5 show two embodiments of the display device 3. The embodiment of the display device 3 shown in FIGS. 2 and 3 is usually provided in all three surge arresters. It has a potential-carrying part 2 which is electrically conductively connected to an earthable power connection of the surge arrester A _R , A _S , A _T. The display device 3 also contains a two-part metal housing 4 made of a material that conducts electricity well, such as aluminum or an aluminum alloy, which is fastened to a switching element 5 of the display device 3.

The switching element 5 comprises a cylinder-symmetrical, gas-tight formed insulating material housing 6 made of a brittle material, such as a highly filled polymer based on an epoxy, and two cylindrically symmetrical, led into the insulating material housing and in each case at one of the ends of the insulating material housing 6 held electrodes 7, 8. The two electrodes 7, 8 are standing one above the other on the axis of the insulating material housing 6 arranged and form at mutually facing free ends, of which the electrode 7 is designed as a tip Isolierstoffgehäuse 6 spark gap 9. The each other facing end sections of the electrodes 7, 8 are connected to the power connections one connected in parallel to the spark gap 9 and preferably designed as a fuse or PTC thermistor Resistor 10 connected. The resistor 10 is dimensioned in such a way that it is still held by the surge arrester 1 High current surge value, for example of 100 kA 4/10 µs can, and that when loaded above a predetermined Period, for example 0.1 ms, with one above one predetermined limit value, for example 20 A, its electrical conductivity, such as by melting or through a PTC transition, suddenly reduced. Inside the Isolierstoffgehäuses 6 not far from the spark gap 9 is one Explosive charge 11 attached, the amount of which is dimensioned that when the charge is ignited, the insulating housing 6 in at least two away from each other and one of each parts holding two electrodes 7, 8 can be detonated.

The metal housing 4 is of two different diameters having shells 12, 13 formed, each with their bottoms are held at opposite ends of the switching element 5.

The shell 12 having the larger diameter takes the the smaller diameter shell 13. The shell 12 has an opening in its bottom through which a galvanic part 2 of the surge arrester connected and an external thread connection of the Electrode 7 is guided. The shell 12 is not by means of a designated nut firmly with the upper end of the switching element 5 connected. At its edge, the shell 12 carries at least one ins Contact element 14 directed inside the shell, which is ring-shaped is formed and has an inner cone. This contact element 14 is provided with an internal thread, which with a External thread of the shell 12 cooperates. Furthermore, the Shell 12 blow-out openings 15 for compressed gas. These blowouts can be restrained with a solid part inside the case Provide filters and be designed so that escaping compressed gas is guided in a predetermined direction.

The shell 13 also has an opening in its bottom, through which an external thread has an earth potential laid connection of the electrode 8 is guided. The shell 13 is by means of an unspecified nut firmly with the lower end of the switching element 5 connected. The shell 13 carries on her from the shell 12 covered outside, for example as Color coating formed display element 16. The shell 13 is flared like a cone and is in the area of the shell edge on the outside as an electrical contact element 17 formed which on the inner cone of the annular contact element 14 is adjusted. The inside of the metal case 4 is by one from the bottom of the shell 13 to the edge of the shell 12 guided cover 18 completed.

The optical waveguide L is with its section LA inside of the metal housing 4 out. For this purpose, the shell 12 two diametrically arranged bushings for the optical waveguide section LA on which the optical waveguide section LA, to the shell 13 provided inside the metal housing to lead. In the shell 13 are two through openings for the Optical fiber section LA provided. On the outside of the Shell 12 are two connecting parts of two fiber optic connectors 19, 20 attached. The optical fiber section LA becomes practically straight forward from the fiber optic connectors 19 through the shells 12 and 13 inside the Led metal housing 4, covers half the circumference of the Isolierstoffgehäuse 6 on the shortest route and will be practically again straight through the shells 13 and 12 to the fiber optic connector 20 led.

Unter normalen Betriebsbedingungen führt jeder der Überspannungsableiter A_R, A_S, A_T lediglich einen kleinen Leckstrom, welcher typischerweise im mA-Bereich liegt. Dieser Leckstrom fliesst vom potentialführenden Teil 2 über die Elektrode 7, den Widerstand 10, die Elektrode 8, das mit dieser Elektrode 8 mittels einer Schraubverbindung galvanisch verbundene flexible Erdungskabel E und die Halterung G zur Erde ab. In entsprechender Weise werden vom Überspannungsableiter noch gehaltene Stromstösse, beispielsweise bis 100 kA 4/10µs, welche als Folge von Überspannungen durch den Ableiter fliessen, zur Erde abgeführt, ohne dass die Anzeigevorrichtung 3 anspricht.

The operation of a surge arrester provided with such a display device 3 is as follows:

Under normal operating conditions each of the surge arrester A _R, A _S, A _T results in only a small leakage current, which is typically in the mA range. This leakage current flows from the potential-carrying part 2 via the electrode 7, the resistor 10, the electrode 8, the flexible grounding cable E, which is electrically connected to this electrode 8 by means of a screw connection, and the holder G to the ground. Correspondingly, current surges still held by the surge arrester, for example up to 100 kA 4/10 μs, which flow through the arrester as a result of overvoltages, are dissipated to earth without the display device 3 responding.

A continuously emitted in the evaluation AW of the control room by the light source LQ signal is first passed through a cooperating part of the optical waveguide L to the surge arrester A _T, passes through the optical fiber connector 19, the optical waveguide section LA, the optical fiber connector 20 and the thereto connecting part of the optical waveguide L to the surge arrester A _S , from there in a corresponding manner to the surge arrester A _R and via an adjoining part of the optical waveguide L guided as a loop to the receiver FW of the evaluation device AW. As long as the light signal arrives at the receiver FW, the surge arresters A _R , A _S , A _{T work} correctly. This can be indicated, for example, by activating the green control lamp KG.

Instructs the surge arrester or in a corresponding manner other electrical apparatus, for example an insulator Switch or a transformer, or an isolator one High-voltage system, a defect, so a fault current flows in the A or even kA range due to that acting as a current sensor ohmic resistance 10. The resistance 10 is strongly heated and goes within a few ms, for example by melting or a PTC transition, into a high impedance state. The fault current now commutates into arcing the spark gap 9 containing current path. The in the area of the spark gap 9 arranged explosive charge 11 is by the forming Arc ignited. The pressurized gas that forms suddenly blows up the brittle insulating material housing 6 then drives the electrode 8 and the rigidly connected to it Shell 13 down to the state shown in Fig.3 Display device 3 is reached. The compressed gas is through the Blow-out openings from the inside of the shells 12 and 13 enclosed metal housing 4 ejected. At the destruction of the insulating material 6 resulting splinters are from Metal housing 4 retained in the interior of the housing.

During the downward movement of the shell 13, the Optical waveguide section LA destroyed and the Light source LQ led light signal to the receiver FW interrupted. Instead of the green KG, the red one now lights up Control lamp KR lights up and signals in the control room that one of the three surge arresters is defective.

In the state shown in FIG. 3, they have been used as a contact element 17 formed conical widening of the shell 13 and the ring-shaped contact element 14 of the fixed Shell 12 jammed. The fault current is no longer over the Spark gap 9 of the switching element 5 led, but now flows via the shell 12 electrically connected to the electrode 7, the mutually contacted contact elements 14 and 17 and the Shell 13 galvanically connected to the electrode 8 to earth. The portion of the shell 12 carrying the display element 14 is now become visible and signals an observer on site the defective surge arrester. The defective surge arrester can now be removed and replaced with a new arrester be replaced. Here, the optical waveguide section LA simply plugged into the fiber optic cable L.

In the embodiment of the surge arrester according to FIGS. 4 and 5, one of both ends of the section LA is connected to a connecting part of the plug connection 19. The other end of LA is closed by a reflector 21. The reflector 21 does not necessarily have to be attached to the shell 12, but can alternatively also be attached to a region of the outer surface of the shell 13 facing the plug connection 19. The section LA can then be omitted and the reflector 21 is then part of a reflection light barrier. Such a surge arrester is executed in the series circuit of three surge arrester A _R, A _S, A _T away from the central evaluation device AW furthest surge A _R.

When fault current-free operation of the three arresters continuously emitted in the evaluation AW of the control room by the light source LQ signal is passed through the arrester and A _T A A _{R S} to the surge arrester. After reflection on the reflector 21, the signal reaches the receiver FW of the evaluation device AW. If the surge arrester A _{R has} a defect, the display device 3 responds and interrupts the light signal led from the light source LQ to the reflector 21 and thus to the receiver FW by destroying the optical waveguide section LA or by moving the shell 13.

LIST OF REFERENCE NUMBERS

A _R , A _S , A _T

Surge arresters

AW

evaluation

e

ground wire

FW

receiver

G

bracket

I

Post insulators

KG, KL

warning lights

L

optical fiber

LA

Optical waveguide section

LQ

light source

R, S, T

phase conductor

TR

transformer

2

potential-carrying part

3

display device

4

metal housing

5

switching element

6

Insulated

7, 8

electrodes

9

radio link

10

resistance

11

explosive charge

12, 13

Peel

14

contact element

15

exhaust openings

16

display element

17

contact element

18

cover

19, 20

Fiber optic connectors

21

reflector

Claims (15)

1. Electrical apparatus, in particular a surge voltage protector (A_R, A_S, A_T), having an optical fibre section (LA), acting as a sensor, for detecting the position of a moveable part of the apparatus, and having connecting means for an optical fibre (L) for transmitting a signal, emitted by the optical fibre section (LA) given a change in position of the moveable part, to a central evaluation device (AW), in the case of which the optical fibre section (LA) is held in such a way that it is destroyed after the change in position of the moveable part, characterized in that the connecting means comprise a first optical fibre connector (19, 20), in that the optical fibre section (LA) is led to an optical display device (3) which is connected in an electrically conducting fashion to an earthable part of the electrical apparatus, in that the display device (3) has a two-part metal housing which supports an optical display element (16) and surrounds a switching element (5) and in that, upon the occurrence of a fault current conducted by the apparatus, a moveable first part, supporting the display element (16), of the metal housing (4) cooperates with the second part of the metal housing (4), thus making the display element (16) visible and forming an electrical connection which takes over the fault current.
2. Electrical apparatus according to Claim 1, characterized in that one of the two ends of the optical fibre section (LA) is connected to a connecting part of the first optical fibre connector (19), and the other end is connected to a connecting part of a second optical fibre connector (20) or a reflector (21).
3. Electrical apparatus according to Claim 2, characterized in that the connecting part, connected to the optical fibre section (LA), of the first and/or the second optical fibre connector (19, 20) and/or the reflector (21) are fastened to the electrical apparatus.
4. Electrical apparatus according to one of Claims 1 to 3, characterized in that the metal housing (4) is formed by two shells (12, 13) of different diameter, the bottoms of the two shells (12, 13) each being held at opposite ends of an insulating housing of the switching element (5), and the first shell (12), having the larger diameter, accommodating a second shell (13), which has the smaller diameter and supports the display element (16) on its outside.
5. Electrical apparatus according to Claim 4, characterized in that the second shell (13) is widened like a cone, and in that the first shell (12) supports on its edge at least one contact element (14) which is directed into the shell interior and, upon displacement of the two shells (12, 13), makes contact with the conically widened part of the second shell (13), forming the electrical connection in so doing.
6. Electrical apparatus according to one of Claims 4 or 5, characterized in that a spark gap (9) connected in an electrically conductive fashion to a non-isolated part (2) of the apparatus, and an explosive charge (11) are provided in the insulating housing (6) of the switching element (5).
7. Electrical apparatus according to Claim 6, characterized in that an ohmic resistor (10) is connected in parallel with the spark gap (9).
8. Electrical apparatus according to one of Claims 4 to 7, characterized in that the optical fibre section (LA) is led through the first shell (12) to the second shell (13) provided in the interior of the metal housing (4).
9. System for displaying the state of the electrical apparatus (A_R, A_S, A_T) according to one of Claims 1 to 8, having the central evaluation device (AW) and having the optical fibre (L), characterized in that the central evaluation device (AW) has a light source (LQ), which continuously feeds a light signal into the optical fibre (L) during operation of the electrical apparatus, as well as a receiver (MW) which detects the fed-in light signal after passage through the optical fibre section (LA) held on the electrical apparatus.
10. System according to Claim 9, characterized in that the optical fibre (L) is constructed in the form of a loop whose one end is operationally connected to the light source (LQ) and whose other end is operationally connected to the receiver (FW).
11. System according to Claim 9, characterized in that the optical fibre (LQ) is constructed in the form of a spur line whose one end is operationally connected to the light source (LQ) and whose other end is terminated by a reflector (21).
12. System according to one of Claims 9 to 11, characterized in that in the cable run of the optical fibre (L) at least one further electrical apparatus (A_S, A_R) having a further section (LA) of the optical fibre (L) is connected in series with the electrical apparatus (A_T).
13. System according to Claim 12, characterized in that instead of an optical fibre section (LA), the apparatus (A_R) furthest removed in the series circuit of the electrical apparatuses (A_R, A_S, A_T) of the central evaluation device (AW) includes a reflected-light barrier which is fed by the light source (LQ) via the optical fibre (L) and feeds into the receiver (FW) via the optical fibre (L).
14. System according to one of Claims 12 or 13, characterized in that the electrical apparatuses (A_R, A_S, A_T) are in each case assigned a phase (R, S, T) of a multiphase network.
15. System according to Claim 14, characterized in that each of the electrical apparatuses is suspended with a high-voltage terminal on an overhead conductor of the multiphase network and is fastened to a grounded holder (G) by means of a post insulator (I).

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