DD200699A1 - METHOD AND CIRCUIT FOR DETERMINING INTERCONNECTION OF HIGH VOLTAGE SWITCHES - Google Patents

Abstract

The application is particularly given in the monitoring of the reliability of the switch. It is an object of the invention to measure and process the actual stress of the circuit breaker in order to perform the proper control and maintenance of the switches. The invention has for its object to provide a method and a circuit arrangement which determines and stores a characteristic size for each switching cycle and each switch pole, which can be used to assess the state of the switch and the Loeschmittels. After the solution, the current-time surface of the arc current occurring between the switch contacts is measured separately for each switching cycle and for each switch pole and accumulatively stored and displayed as normalized value, the memory contents of the accumulative memory per switch pole being an equivalent to the wear caused by the arc current Loeschmediums is, when it exceeds a signaling occurs. The circuit arrangement ensures the implementation of the method. figure

Description

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Method and. Circuit arrangement for determining the extinguishing agent wear in high-voltage switches

Field of application of the invention

The invention relates to a circuit arrangement for determining the Löschmittelverschleißes at high voltage switch ^ The state of wear of the extinguishing agent is displayed directly without a - Activation, des- high-voltage switch is required. The application is especially given when monitoring the reliability of the switch *

Characteristic of the known technical solutions According to the binding definition according to TGL 26096/01 edition 1p78 "Reliability in the technology; terms" is to be understood under the reliability of a device its property, "predetermined punctures under observance of the values of specified parameters within given limits, which the given operating modes and conditions of use, maintenance, storage and transport, over a certain time interval to fulfill "" For the interests of the high voltage switch, the definition in 0, a _o definition is also important, therefore, instead of the time interval and in other units may occur measurable amount of work _o When high-voltage switches are the first of which demanded him switching operations "Their intensity and number per unit of time (Sehalthäufigkeit) are extremely different depending on the area of the switch, and consequently to face wear and Availability after a certain period of use

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Each switch has a considerably different appearance _o This fact, ie the actual load on the switches, must be taken into account when determining maintenance cycles _o Circuit breakers must be able to withstand the requirements of TGL 16441 Edition 12 _O 69 "High Voltage Switchgear; Switches and Disconnectors; "Perform at least 3 trips of short-circuit currents and 1000 operations in de-energized state." Both values are indicative of warranty, and by no means indicate the limit of wear of the devices * The actual limits of wear are higher ₃ in some cases considerably higher.

For the implementation of proper control and maintenance of the switches knowing the actual stress is _o fundamental condition for the stress test application time, the usually is not a problem, nor is the number of switching cycles since the switches are generally equipped with counters for several years * » It is much more difficult to determine the load on the switches by means of short-circuit disconnections. "Good help is provided by conscientiously kept operating diaries or" life cycle files. "A relief is to be expected from the counting module of the CSIM 3-12." Protection and operating trips are counted separately so that In order to make it easier to make a real assessment of actual wear and tear "Great importance is still attached to the visual inspection of the equipment, as specified in detail in the operating instructions, as it will reduce the level of wear and tear ng complex detected. It is not possible to give general recommendations for performing prophylactic measurements as a substitute for visual control. "

The exact determination of the extinguishing agent wear is difficult if the knowledge of the stress is not sufficiently precise. The visual control does not provide useable results here, even after a few shifts

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The measurement of the breakdown voltage also provides no reference values, because by the resulting soot, the value required in the TGL can be exceeded even after a few short cut outs, what but for the switch means no danger «

A measure of the extinguishing agent wear is the carbon black content · As a feasible with reasonable effort method for determining the carbon black content, the acceleration of the natural sedimentation by a suitable solvent (z _o B · η-hexane in a mixing ratio 1: 1) suggested «From the measured carbon black content The extinguisher wear and thus any necessary replacement of the extinguishing agent can be determined taking into account the type of switch. "The implementation of this method requires the activation of the cell in which the high voltage switch is inserted and the removal of a sample of the extinguishing medium a certain number of nominal load circuits or "short circuits" are carried out *

Object of the invention

It is an object of the invention to measure and process the actual stress of the high-voltage switch in order to be able to carry out the proper control and maintenance of the circuit

Explanation of the essence of the invention

The invention has for its object to provide a method and a circuit arrangement which forms and stores a characteristic size for each switching cycle and each switch pole, which can be used to assess the state of the extinguishing agent in the high voltage switch.

According to the invention the object is achieved in that the current-time surface of the occurring between the switch contacts-

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the arc current is measured separately at each switching cycle and for each switch pole and stored and displayed cumulatively as a normalized value, the memory content of the Kunriilativspeichers per Schalterpol an equivalent of the caused by the arc current wear of the extinguishing medium is displayed or _{0 is} signaledo

The method is realized by a circuit arrangement having a current transformer whose output is applied via an ohmic load and a rectifier to a sample-and-hold circuit, which is detected when occurring arc, which is arranged in the high voltage switch UV-sensitive component , via an Initiatorlogik and control logic starts and for the duration of the arc current flow, the measurement signal via an A / D converter digitally processed and stored cumulatively, this value is displayed or »signals

embodiment

The invention will be explained below with reference to an embodiment "The accompanying drawing shows the circuit arrangement for determining the state of wear of the extinguishing agent in the high voltage switch," The current transformer 1 applies to the example ohmic burden 2, the secondary current, so that on the burden.2 a corresponding AC voltage can be picked up »The rectifier converts this AC voltage into a DC voltage This process is always the same way _o In the high voltage switch 4 via UV-sensitive devices 5, such as photodiodes, phototransistors, Photonthyristoren, etc. the arc of each switching cycle detected and The time duration of the arc pulse is decisive. For the duration or the lateral length of the arc of a switching cycle, its current-time surface is determined by the circuit arrangement, the sum of these amounts being an equivalent for the Ver represents wear of the extinguishing medium. The intensity of the pulse is important in that this UV-sensitive

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Component 5 must be interconnected with the initiator logic β in such a way that the arc effect in the extinguishing medium can be evaluated electronically. »To the rectifier 3, a sample-and-Eold-3evaltung 7 with the control logic 8 connects through the S / H circuit is it possible for each instantaneous value of the DC voltage to be digitized to be detected with sufficient accuracy in a very short time and recorded for the time required for exact analog-to-digital conversion? The control logic 8 has two operating states, once the signal output of the S / H The instantaneous value of the signal input voltage is determined by the rectification »The duration of the arc pulse determines the duration of the arrest, while the exact evaluation of this takes place with the aid of the initiator logic« Pur the duration of the arc pulse can be an A / D Conversion 9 are made. The bit pattern generated in this way is stored cumulatively in a transient memory with TOR circuit 10. Depending on the requirement, this memory can be designed as static or dynamic RAM. These types of memory depend on an intact power supply. Is the information retained in the memory in the event of a power failure demanded that can be over

p energy-saving RAMs in CMOS or I! technology or to be realized with RAMs with sleep state in conjunction with a backup battery _e Data retention after failure of the power supply without backup battery is guaranteed by the use of bubble memories that work in a block-oriented manner Organization of the data entry or »reading again takes over the control logic 8 _e via a keypad, the specification of the limit value, ie the wear limit e as well as the manual query of the current state of wear, the start / stop and lock operation and clearing the memory after a revision ₉ which was connected with a change of the poles or the extinguishing agent, etc. _c «

The display / signaling 12 contains the known scope of clearly arranged illuminated numbers and signaling types «

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Sine complex monitoring of many high-voltage switch in the context of large power installations is centrally conventional as well as microcomputer controlled possible, "This central monitoring is particularly advantageous through the use of one-chip-iitÜkrocomputer and an integrated display ο The solution according to the invention, the query of the current state of wear is separate for each Schalterpol possible, with a conventional limit message _{9 can} also be made for each switch pole ₉ ,. The level at which the limit value message is displayed is variably adjustable and can be defined by the manufacturer for each type of switch ,,

Claims (1)

- 7 -. I J 4 I L D invention claims o Method for determining the extinguishing agent wear in high-voltage switches, characterized in that the current-time surface of the arc current occurring between the switch contacts is measured separately at each switching cycle and for each switch pole and stored as a normalized value cumulatively and displayed, the memory contents of the cumulative memory per switch pole is an equivalent for the wear of the extinguishing medium caused by the arc current « 2 _β circuit arrangement for carrying out the method according to item 1, with an electronic Meßwertauswerteeinheit, characterized by a current transformer (1) whose output via an ohmic burden (2) and a rectifier (3) to a sample-and-hold circuit (7 ) is applied, which is detected by a high voltage switch (4) arranged in the UV-sensitive device (5) via an initiator logic (6) and control logic (8) starts and for the duration of the arc tromflusses the measurement signal via a A / D converter (9) is digitally processed and stored cumulatively. See 1 page drawing,