Method for testing multiple spatially distributed protective devices of an energy supply network, and corresponding testing system

Abstract

A method for testing multiple spatially distributed protective devices of an energy supply network. Each of the protective devices is configured to, in the event of a fault occurring in the energy supply network, isolate the fault in the energy supply network. The method comprises: producing an initial test sequence; outputting of the test sequence to the protective devices; detecting outputs of the protective devices that the protective devices output on the basis of the test sequence; analyzing the outputs and generation of inputs for the protective devices depending on the outputs. If the inputs are not part of the test sequence, these inputs are incorporated into the test sequence and the outputting step proceeds. Otherwise, all outputs of the protective devices are evaluated. Each test sequence comprises inputs in the form of process variables of the energy supply network for at least one of the protective devices.

Claims

1. Method for testing multiple spatially distributed protective devices of an energy supply network, wherein each of the protective devices is configured in order so as to, in the event of a fault occurring in the energy supply network, isolate the fault in the energy supply network, wherein the method comprises the following steps: a: production of an initial test sequence, b: outputting of the test sequence to the protective devices, c: detection of outputs of the protective devices that the protective devices output on the basis of the test sequence, d: analysis of the outputs and generation of inputs for the protective devices depending on the outputs, wherein, if the inputs are not part of the test sequence, these inputs are incorporated into the test sequence and step b is proceeded with, while otherwise step e is proceeded with, and e: evaluation of all outputs of the protective devices, wherein each test sequence comprises inputs in the form of process variables of the energy supply network for at least one of the protective devices.

2. Method according to claim 1, wherein the outputs of the at least one of the protective devices comprise a switch opening command, with which a circuit breaker is opened to isolate the fault, and/or a reclose command, with which an isolation of a fault is cancelled again by closing a circuit breaker.

3. Method according to claim 1, wherein the generation of inputs takes place depending on the outputs, in that starting out from the outputs, changes in the process variables of the energy supply network are determined with reference to a model of the energy supply network.

4. Method according to claim 3, wherein the model is a static, a dynamic or a transient model.

5. Method according to claim 1, wherein upon the occurrence of a fault in the energy supply network, a command to open a circuit breaker is outputted by each protective device in order to isolate the fault.

6. Method according to claim 1, wherein for each of the protective devices the process variables of the energy supply network are detected via a transformer connected to the energy supply network, and it is determined depending on the process variables whether a fault is present in the energy supply network.

7. Method according to claim 1, wherein one of the protective devices is connected via a communications channel to another of the protective devices, that the protective device acquires information from the other protective device via the communications channel, and wherein it is decided depending on the information whether, in the event of a fault occurring in the energy supply network, the fault is isolated by the protective devices.

8. Method according to claim 1, wherein the method is executed automatically by a central control device.

9. Method according to claim 1, wherein output steps are specified, with each of the output steps comprising at least one input, and the output steps being outputted as the test sequence to the protective devices in an order dependent on trigger events, wherein each trigger event is dependent on at least one event from an event group, wherein the event group comprises: expiry of a predetermined timespan, arrival of a certain item of data from one of the protective devices via a communications channel at another of the protective devices, and a switch setting of a circuit breaker is changed.

10. Testing system for testing multiple protective devices of an energy supply network arranged at spatially distributed locations, wherein the testing system comprises a control device and multiple testing devices, wherein at least one of the testing devices is present at each location of the protective devices, wherein the control device has a communications connection to each of the testing devices, wherein each of the testing devices is configured to test at least one of the protective devices, which is present at the same location as the respective testing device, and wherein the testing system is configured to, in the event of a fault occurring in the energy supply network, isolate the fault in the energy supply network by: producing an initial test sequence; outputting the test sequence to the protective devices; detecting outputs of the protective devices that the protective devices output on the basis of the test sequence; analyzing the outputs and generating inputs for the protective devices depending on the outputs wherein, if the inputs are not part of the test sequence, the inputs are incorporated into the test sequence prior to the outputting of the test sequence to the protective devices; and evaluating all outputs of the protective devices, wherein each test sequence comprises inputs in the form of process variables of the energy supply network for at least one of the protective devices.

11. Testing system according to claim 10, wherein the control device is integrated into one of the testing devices.

12. Control device for a testing system for testing multiple spatially distributed protective devices of an energy supply network, wherein the control device is configured to communicate with multiple testing devices assigned respectively to the protective devices, wherein each testing device is configured to test at least one of the protective devices, wherein each of the protective devices is configured in order so as to, in the event of a fault occurring in the energy supply network, isolate the fault in the energy supply network, the control device configured to; produce an initial test sequence; output the test sequence to the protective devices; detect outputs of the protective devices that the protective devices output on the basis of the test sequence; analyze the outputs and generate inputs for the protective devices depending on the outputs wherein, if the inputs are not part of the test sequence, the inputs are incorporated into the test sequence prior to the outputting of the test sequence to the protective devices; and evaluate all outputs of the protective devices, wherein each test sequence comprises inputs in the form of process variables of the energy supply network for at least one of the protective devices.

13. Computer program product with computer-readable instructions stored on it, which are configured in such a way that upon execution of these instructions by a computer, a method for testing multiple spatially distributed protective devices of an energy supply network is executed, wherein each of the protective devices is configured in order so as to, in the event of a fault occurring in the energy supply network, isolate the fault in the energy supply network, wherein the method comprises the following steps: a: production of an initial test sequence, b: outputting of the test sequence to the protective devices, c: detection of outputs of the protective devices that the protective devices output on the basis of the test sequence, d: analysis of the outputs and generation of inputs for the protective devices depending on the outputs, wherein, if the inputs are not part of the test sequence, these inputs are incorporated into the test sequence and step b is proceeded with, while otherwise step e is proceeded with, and e: evaluation of all outputs of the protective devices, wherein each test sequence comprises inputs in the form of process variables of the energy supply network for at least one of the protective devices.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) The present invention is explained in greater detail below with reference to the enclosed drawing, with reference to preferred embodiments according to the invention.

(2) In FIG. 1 a testing system according to the invention is shown together with an energy supply network, which is protected by two protective devices.

(3) FIG. 2 shows a flow chart of a method according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

(4) FIG. 1 shows an energy supply network in the form of a single transmission line 3. According to the invention, an energy supply network can comprise multiple transmission lines, other high-voltage lines, parallel lines and transformers, which are connected in the form of a network. The transmission line 3 ends at both ends respectively at a bus bar SS.sub.1, SS.sub.2 in different substations UW.sub.1, UW.sub.2. Inside the respective substation is a circuit breaker, with which the electrical connection between the part of the transmission line 3 connecting the two substations UW.sub.1, UW.sub.2 and the respective bus bar SS.sub.1, SS.sub.2 can be interrupted. Moreover, located inside the respective substation UW.sub.1, UW.sub.2 is a transformer, with which a heavy current (phase current) carried by the transmission line 3 and a high voltage present at the transmission line 3 are converted, wherein the result of this conversion in the form of a current and a voltage of low amplitude (e.g. 1 A and 100 V) are supplied to the respective protective device as process variables. The respective protective device monitors the energy supply network and the transmission line 3 with reference to these process variables. The point at which the respective circuit breaker and the respective transformer are located is designated K.sub.1 or K.sub.2 in FIG. 1.

(5) When a fault 5 (for example, a short circuit) occurs in the transmission line 3, the respective protective device SE.sub.1; SE.sub.2 detects this fault 5 with reference to the process variables, in that the current increases above a current threshold or the voltage falls below a voltage threshold, for example. As soon as the respective protective device SE.sub.1; SE.sub.2 detects the fault 5, it outputs a switching command to the circuit breaker assigned to it, in order to interrupt the electrical connection and thus isolate the fault 5. After a predetermined pause time following detection of the fault 5, the respective protective device SE.sub.1; SE.sub.2 outputs a switching command to the circuit breaker assigned to it in order to restore the electrical connection. If the fault 5 still exists at this time, the respective protective device SE.sub.1; SE.sub.2 detects this with reference to the process variables of the transmission line 3 supplied to it and outputs a further switching command, in order to interrupt the electrical connection again using the circuit breaker assigned to it.

(6) Moreover, the two protective devices are connected by communications technology via a communications channel 2. Via this communications channel 2 the two protective devices SE.sub.1, SE.sub.2 can transmit certain information (e.g. process variables, switching commands) to one another virtually in real time.

(7) To test the protective devices SE.sub.1, SE.sub.2, a testing device PE.sub.1, PE.sub.2 exists in each substation UW.sub.1, UW.sub.2, wherein the respective testing device PE.sub.1, PE.sub.2 is connected by a testing line PL.sub.1, PL.sub.2 to the protective device SE.sub.1; SE.sub.2 arranged in the same substation UW.sub.1, UW.sub.2 In addition, a central controller 1 exists, which is connected via a communications line 6 and a WAN communications connection 4 to both testing devices PE.sub.1, PE.sub.2.

(8) The testing devices PE.sub.1, PE.sub.2 are each equipped with a very accurately working clock, wherein the clocks of the testing devices PE.sub.1, PE.sub.2 are mostly synchronised by GPS, in order to show exactly the same time. Synchronous clocks are of great importance when applying the test sequence and when detecting the outputs of the individual protective devices SE.sub.1, SE.sub.2.

(9) To test the protective devices SE.sub.1, SE.sub.2, the protective devices SE.sub.1, SE.sub.2 are separated from the energy supply network 3 by interrupting the control lines SL.sub.1, SL.sub.2. During the test the protective devices SE.sub.1; SE.sub.2 receive the process variables normally acquired by them via the transformer via the respective testing line PL.sub.1; PL.sub.2, and output the switching commands that are outputted via the control line SL.sub.1, SL.sub.2 in normal operation via this testing line PL.sub.1; PL.sub.2. The energy supply network is thus not protected by the protective devices SE.sub.1, SE.sub.2 during the test, but it is not disturbed by switching commands initiated by the test either.

(10) FIG. 2 shows a flow chart of a method according to the invention for testing multiple spatially distributed protective devices SE.sub.1, SE.sub.2 of an energy supply network.

(11) In step S1 a test sequence is produced for one, more or all protective devices SE.sub.1, SE.sub.2 to be tested. It is to be verified using this test sequence whether the respective protective device SE.sub.1; SE.sub.2 behaves correctly at the transition from normal operation to a fault state (i.e. the respective protective device SE.sub.1; SE.sub.2 detects a fault in the energy supply network). To do this, process variables, which would be detected in the event of a fault in the energy supply network or the transmission line 3, are supplied to the respective protective devices SE.sub.1, SE.sub.2 via the testing line PL.sub.1; PL.sub.2.

(12) In step S2, the test sequence is distributed by the control device 1 to the testing devices PE.sub.1, PE.sub.2 and outputted by these testing devices PE.sub.1, PE.sub.2 to the respective protective devices SE.sub.1, SE.sub.2 at exactly the same time, in that corresponding test patterns are supplied to the respective protective device SE.sub.1; SE.sub.2 via the respective testing line PL.sub.1; PL.sub.2. The reaction of the protective devices SE.sub.1, SE.sub.2 to these test patterns is detected in step S3, in that the outputs of the respective protective device SE.sub.1; SE.sub.2 are detected by the respective testing device PE.sub.1, PE.sub.2 on the respective testing line PL.sub.1, PL.sub.2 and are provided with a very accurate time stamp. These outputs comprise switching commands to the circuit breakers assigned to the respective protective device SE.sub.1; SE.sub.2, for example.

(13) In step S4, the outputs (in particular switching commands) detected in the previous step S3 are analysed. In this analysis it is verified whether an output of a protective device SE.sub.1, SE.sub.2 changes the process variables of the energy supply network 3, which is the case, for example, if the outputs comprise a switching command to open a currently closed circuit breaker. With the aid of a model of the energy supply network 3, the process variables at all the points K.sub.1, K.sub.2 of the energy supply network 3 at which the process variables are tapped by the protective devices SE.sub.1, SE.sub.2 in normal operation (non-testing operation) are simulated in this case, starting out from the switching commands detected in step S3. From the process variables simulated in this way, corresponding inputs are yielded for the protective devices SE.sub.1, SE.sub.2. (For example, a switching command of protective device SE.sub.1 leads to the opening of the circuit breaker at K.sub.1 and thus to a change in the process variables at point K.sub.2, which leads in turn to a change in the inputs supplied to protective device SE.sub.2 via the testing line PL.sub.2.)

(14) If step S5 is run through at least for a second time, it is verified in step S5 whether the current outputs match the outputs of the previous pass within certain tolerances (deterministic). A negative result of step S5 does not necessarily lead to a negative test result. In a normal case, the method is repeated at a negative result in step S5, wherein the tolerances are increased if necessary. The result of step S5 can also be assessed manually. In this case the method is only repeated following a negative result if the technician supervising the test consents.

(15) In step S6 it is verified whether the inputs generated in the previous step S4 are already contained in the test sequence. This will most probably not be the case in the first pass of step S6 if switching commands were detected in step S3. If inputs exist that are not yet contained in the test sequence, these inputs are incorporated into the test sequence in step S7. Then the method according to the invention resumes again at step S2. It is thus a recursive method.

(16) In a fresh pass of steps S2 to S6, the transition from normal operation to a fault state and from there to the state following switching processes of the circuit breakers initiated by the protective devices SE.sub.1, SE.sub.2 is tested using the test sequence modified in the last step S7. It is verified again here in step S6 whether outputs (in particular switching commands) are present in the previous step S4 that were not yet present in the previous pass. This is the case, for example, if one of the protective devices SE.sub.1, SE.sub.2 outputs a switching command to reclose the circuit breaker assigned to it.

(17) The method runs through the steps S2 to S6 until the protective devices SE.sub.1, SE.sub.2 do not output any further or new outputs (in particular switching commands). If this is the case, the method branches to step S8, in which the outputs of the protective devices SE.sub.1, SE.sub.2 that were detected by the corresponding testing devices are evaluated to produce a testing result.

(18) The incorporation of further inputs into the test sequence normally also comprises the incorporation of target outputs, which are to be outputted by the protective devices SE.sub.1, SE.sub.2 on the basis of the newly incorporated inputs. For this reason also it is possible that it is verified, for example, in step S4 in the analysis of the outputs whether the outputs of the protective devices SE.sub.1, SE.sub.2 detected respectively by the testing devices PE.sub.1, PE.sub.2 are correct, or whether a malfunction of the protective devices SE.sub.1, SE.sub.2 was already detected, which could lead to a negative test result and thus to a premature termination of the test.

(19) Moreover, in each further pass of the steps S2 to S6 it can be verified whether the outputs of the protective devices SE.sub.1, SE.sub.2 correspond to the outputs of the protective device SE.sub.1; SE.sub.2 in the previous pass in each case, thus whether in particular the same switching commands have been outputted. If this is not the case, the test can likewise be terminated with a negative result.

REFERENCE SYMBOL LIST

(20) 1 Controller 2 Communications channel 3 Transmission line 4 WAN communications connection 5 Fault 6 Communications line K.sub.1, K.sub.2 Nodes (circuit breaker and transformer) PE.sub.1, PE.sub.2 Testing device PL.sub.1, PL.sub.2 Testing line SL.sub.1, SL.sub.2 Control line S1-S8 Method step SS.sub.1, SS.sub.2 Bus bar USW.sub.1, USW.sub.2 Substation