DE3505818A1 - MONITORING AND CONTROL DEVICE FOR SWITCHGEAR - Google Patents

Description

Licentia Patent-Verwaltungs-GmbH 15.02.85 Theodor-Stern-Kai 1 PTL-HH / Era / bl D-6000 Frankfurt 70 OL 84/14

The invention relates to an arrangement for monitoring, Control and evaluation of the influencing factors, which are necessary Influence maintenance intervals of switchgear.

These influencing factors are recorded, linked to one another, weighted and compared with a given behavior pattern and gained a flexible maintenance indicator from it.

It is often the case with switching devices or switchgear assemblies desirable when maintenance is required to signal to the outside world. Especially with the switchgear for larger nominal currents, the knowledge is e.g. B. des Contact wear (main shell 11 pieces or in the case of multi-level Systems also tear-off contacts), the contact pressure, the State of arc chambers, and various mechanically stressed Parts of particular interest for the reliability of a system.

So far, mechanical or electrical counting devices have been used with which the number of mechanical switching cycles is registered. There are also burn-up indicators for the Known switching pieces that are mechanically operated using levers or cables being controlled; likewise the recording of the number of operating hours via clock counters.

Temperature recorders can be used for the temperature / time behavior as well as interception circuits for fault messages, d. H. report an unwanted switch tripping.

Will maintenance or repairs after a rigid Scheme according to the number of mechanical switching cycles or executed according to the number of operating hours, inevitably remain many other influencing factors are not taken into account. The switchgear manufacturers must make recommendations for these maintenance intervals are based on standardized operating conditions.

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In fact, however, when the switching devices are used, the Partly significant deviations from this assumed location. Then reliability statements are for a preventative Repair of complete switchgear assemblies (e.g. industrial plants, power plants) very problematic. So z. B. only three power shutdowns with the limit switching capacity cause the same contact erosion on the main contacts of a circuit breaker as five thousand Disconnections in the rated current range of the device.

Are the maintenance intervals to achieve a high If the operating reliability is selected to be very small, it is found below In some circumstances an uneconomical use of materials and equipment high maintenance costs.

Maintenance intervals that are too long are at the expense of operational reliability and can endanger people and systems and lead to significant production losses in the event of system downtime to lead. Operating systems that are subject to the immission protection regulations are particularly challenged here.

The state of a switchgear or a switchgear assembly Until now, the operator remains largely unknown between two maintenance dates, and he does not receive any notification of any excessive wear and tear that may have occurred would require immediate action.

The invention is based on the object of a monitoring and To develop control equipment with which it is possible to maintenance flexible without a rigid maintenance schedule, according to the actual requirements of the respective To carry out the application.

The current condition of the device and the degree of wear and tear should be used during the operation of "non-switching device specialists" be recognizable or retrievable. Atypical wear or that Occurrence of errors which affect the ability to function should be signaled. The device is intended to be higher-level monitoring system can work together and over have a certain amount of self-diagnosis.

The object is achieved by the characterizing ¹ Me r kma Ie of claim 1. Such a flexible maintenance interval display consists of an electronic device that links, evaluates and compares with stored, predetermined behavior patterns via different sensors that detect the actually occurring events as well as the current state of the switching device or the switching device combination Recovers maintenance information.

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principle

The invention is therefore based on the principle of measuring critical variables in the new condition of various wear parts, ie O '/. Wear corresponds to 100% expected service life (display games). The respective wear is determined by measuring the number of operations. Characteristic curves (FIG. 1) (linear, degressive or progressive) are obtained as a function of the degree of wear and tear on the number of operations. By extrapolating up to the wear limit (corresponding to the end of the service life), conclusions can be drawn about the residual load I can still be expected. A meaning reversal is also possible.

The empirically determined characteristics of the various wear parts are stored in a read-only memory as a function, digitized with scatter band ', as a set of curves with different Parameters or multi-dimensional as a reference map, if necessary stored in its own computer program.

With suitable sensors, degrees of wear or misc Liss conditions recorded directly or indirectly through linkage calculated from analog data using a dedicated software program. All information obtained in this way is stored in the core element, processed by a microprocessor and the result in the status memory (changeable read-only memory) saved.

According to the content of the state storage z. B. over an LED line of the visual switch device status (Degree of wear) is displayed. It is also alphanumeric display possible with LED or LCD display (e.g. 7-segment display) or the connection via a data bus to a higher-level monitoring service or alarm systems, if necessary with alarms graded according to urgency.

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Function and process

In a preferred embodiment it is provided according to the Completion of the switchgear or switchgear assembly, to reset all state stores to zero and only the date of manufacture in a non-volatile read-only memory to be entered.

From the time of commissioning, all are wear-relevant Events (see Fig. 2) recorded, depending on the level of influence valued differently and as a fictitious "wear and tear scarf number" accordingly summed up and separated into State storage registered. This is followed by a comparison with the reference values specified in the reference map memory, by extrapolation to the wear and tear limit, the present residual value I or the current overall condition determined.

This status information is analog / quasi-analog with LED, LCD or corresponding signaling devices or digitally via a segment display z. B. LCD segment display directly on the switchgear or combination readable. If suitable signal lines are provided, e.g. b. Data bus, fiber optic link, can this information also to higher-level monitoring service or alarm systems are given.

In the case of an overhaul in a larger system (e.g. power plants, industrial company, Ship and the like) can be recognized immediately on the basis of this status information whether the switching device / combination you have to wait for this or the next overhaul.

The query of the current status is even more informative with a test case that connects to the microprocessor via the bus communicates. This allows them to be saved in the state memories Query entered "wear switching numbers" individually, so that, if necessary, it can be seen which wear event led to the acute maintenance notification; whether z. B. increased Contact burns or the high number of mechanical switching cycles the cause are (a kind of self-diagnosis). Are the sensors for short-circuit and overload detection switched, can be z. B. determine whether the contact is eroded by a few short-circuit disconnections or by frequent overload circuits was caused.

If a switchgear assembly is monitored, it can be seen which switchgear in a system is particularly stressed will.

There is a significant advantage in maintenance without a test case, if the display field (e.g. segment display) on the switching device as a query menu field, d. H. Selection of the different State memory by pressing a button and displaying the content on this display field is formed. This results in a very cost-effective, time-saving one selective maintenance with only what is really necessary Work to be carried out.

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F lex ιb Ie maintenance interval [display

After the maintenance work has been carried out, the corresponding State storage, depending on the expansion stage either on The device itself is reset by pressing the S1 button or via the data bus when using the test case. It is there too It is possible to enter the number and scope of the maintenance work carried out in the status memory, so that it is possible at The history of this switchgear is to be recorded for each maintenance protrude.

If shorter maintenance intervals are required due to special operating conditions, the status memories can only be step back to the required level.

FIG. 2 shows a schematic representation of the measured variables detected via suitable, previously known sensors, the change of which is monitored, evaluated directly or determined indirectly by linking dependent data. So z. B. the contact burn di rectly via displacement or angle measuring sensors, via optical position reports or magnetic proximity sensors. Or also indirectly by linking the analog data influencing the burn-up, such as current level, switching voltage, cos./, number of switchings and switching instant (with alternating current), also current gradient di / dt or the time constant T = L / R (at Direct current) in its own software program and comparison with the empirically determined data stored in a map.

Noteworthy is the direct flow of signals from some critical ones Measured variables that occur when predetermined limits are exceeded have "resounding" effect, exceed z. B. the temperature the switching device current path in relation to the flowing Current considerably exceeds a predetermined value, a after Urgency graded alarm can be given or the switching device be switched off immediately. This case could e.g. B. broken or loosened screw or soldered connections enter the current path. Since this fault would not be noticed by the usual overcurrent triggers, it could be Total failure of the device.

The flexible maintenance interval display according to the invention can preferably with different levels of expansion and comfort which are determined by the number of available input channels (sensor inputs), the type of measured value linkage (direct or indirect determination) and ease of use (LED line, Menu field or test case connection).

In one embodiment, interfaces are provided that interact with other external protection systems such as fire and smoke alarms, arc fault monitors, current rise detection systems, property protection fault value reporting systems <JSW 'SC- poss.

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Become the discrete assemblies of this flexible maintenance interval display summarized in terms of hardware or highly integrated, This module can also be used as a functional unit integrate into other devices or monitoring and protection systems. This is especially true if not only individual switching devices, but entire switchgear assemblies (definition according to VDE and IEC) are to be monitored.

3 5 Π B 8 1

In Fig. 3 an embodiment of the invention is shown. In order to solve the above-mentioned task, the following hardware requirements are first of all necessary:

- Power adapter

- Bridges
.3 - Battery

- / UP

with feed from the voltage network or

via the current transformers or both, via bridges

selectable.

for buffered operation of the clock with date

or the / üP

Core element in which all information on the microprocessor converge and be processed.

- Program and read-only memory in which the program for Reference characteristic / UP and the reference characteristic map fixed field memory stores are.

State store

Changeable read-only memory, the data content of which can be changed, but which is not lost in the event of a power failure. The current status of the switching device is shown here saved.

A summary of the two read-only memories in a common component is possible, as the program + reference map memory can be stored in a changeable read-only memory.

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- Clock with date This function is either from the separate

Hardware component or by the / UP Software made a reality. A permanent operation, e.g. B. by buffering the supply voltage must be guaranteed.

- LED line

to display the current switchgear status. It is also possible to use a 7-segment or an alphanumeric display with LED or LCD.

- bus connection

for reporting the switchgear status to higher-level monitoring, service or Maintenance equipment. Not necessarily required.

- button Sl

only required if there is no bus connection to reset the status memory performed maintenance.

- switch S2

- switch S3
- tension

transducer

As an alternative to the voltage transducers for stepped input of the operating voltage or type of voltage used

for the selection of the map or alternatives Either only 1 encoder or 3 encoders for determination the applied switching voltage. A rough classification is sufficient here, z. B. 600 V- or looo V- network.

Current transducer

16 / - temperature-17

transducer

For recording the individual phase currents or - in the case of direct current - the flowing

Current (possibly from current and voltage the cos f. Or with direct current also the current gradient di / dt)

At a suitable point on the switch, e.g. B. in the near » on the contact pieces, for recording the temperature of the current path (s) and a sensor for recording ilor ambient temperature . of the switch gate.

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fa "*

'/ ttr

- Auxiliary contact or suitable sensor for recording the -

Switching cycles.

- Sensor position encoder, light barrier, rotary encoder for direct

the detection of the contact burn.

With the hardware requirements mentioned above, the following Evaluate events or states of the switching device shown in three poles (-2o-):

- Number of mechanical switching cycles through auxiliary contact. If / uP buffering is selected, this evaluation can cover all switching cycles, otherwise only those with pending Supply voltage take place.

- Number of electrical switching cycles through auxiliary contact and Current transducer. ·

- Operating hours by clock with date.

- Storage time by clock with date.

- Indirect condition of the switching device's bearing grease by evaluating the operating time, storage time and number of switching cycles and ambient temperature sensor. When buffering / UP and temperature sensor, the storage temperature can also be evaluated.

- State of the switching contacts (e.g. burn-off) indirectly through evaluation

of the number of electrical switching cycles -

Number of rated current shutdowns Number of overcurrent shutdowns Zl ₅ Ix Ig, Z 2 χ I _E and Z 15 χ Ig

Amount of the respective breaking capacity by taking into account the switching voltage and the cos f Amount of the respective switching capacity Contact wear indirectly via the evaluation of the current and temperature of the respective current path

. JIO BAD ORIGINAL

- State of the switching contacts (e.g. burn-off)

- Directly by measuring changes in the angle or path or the position of parts.

- Condition of the arc extinguishing chambers

indirect evaluation as with switching contacts, but without contact erosion.

State of the switching mechanism indirectly by evaluating the state of the switching contacts (provided on / off switching power) as well as the condition of the bearing grease (operating time, storage time, temperature, number of switching cycles)

Further hardware sensors are conceivable and would significantly increase the accuracy of the evaluation. For example 'The contact wear can also be recorded directly via angle or displacement sensors, so that one does not have to pay attention to the praised ones indirect valuation is required. Suitable sensors (e.g. optics) could also reduce the bearing play monitor the switching mechanism or the position of wear-determining parts.

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Claims (2)

Licentia Patent-Verwaltungs-GmbH 02/15/85 Theodor-Stern-Kai 1 PTL-HH / Em / bl D-6000 Frankfurt 70 OL 84/14 patent claims 1. Monitoring and control equipment for switchgear and switchgear assemblies, characterized in that, to obtain a flexible maintenance indicator, influencing variables that determine the required maintenance intervals influence, recorded by suitable means, linked with one another, weighted and compared with a given behavior pattern. 2. Device according to claim 1, characterized by an electronic Facility, which has different sensors, which actually Record occurring events as well as the current state of the switching device or the switching device combination, linked with one another, evaluated and compares it with stored, predetermined behavioral patterns and extracts maintenance information therefrom.