Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
  • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
  • H02H3/26—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents
  • H02H3/32—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors
  • H02H3/33—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors using summation current transformers
  • H02H3/334—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors using summation current transformers with means to produce an artificial unbalance for other protection or monitoring reasons or remote control
  • H02H3/335—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors using summation current transformers with means to produce an artificial unbalance for other protection or monitoring reasons or remote control the main function being self testing of the device

Definitions

• the invention relates to a method for performing a self-test by a residual current device such as a residual current circuit breaker, wherein the residual current device is to be ready for use, that is coupled to power lines, so that in a closed circuit current flows through the residual current device.
• the invention also relates to a residual current device in which the method according to the invention can be carried out.
• Residual current circuit breakers are known on the market which have the capability to perform a self-test.
• a timer sets the times when the self-test is performed.
• the object is achieved by a method having the features according to claim 1 and a residual current device with the features according to claim 4.
• the method according to the invention it is thus determined whether the current intensity of the current respectively flowing over at least part of the current lines is compatible with a self-test according to a predetermined criterion.
• a time for the self-test is determined taking into account the result of the assessment.
• the determination can take place repeatedly and a self-test can be carried out immediately when the criterion is fulfilled.
• a timing determines when the determining step is performed: namely, after a predetermined polling time interval has elapsed since the last self-test or at a predetermined time (set, for example, as a certain time of day, a low load on the residual current circuit breaker is expected and a self-test is carried out in a meaningful way) take place. If the result of the determination is positive, the self-test is performed. Otherwise, the determination is continued or repeated. The determination is continued in an alternative as long as or repeated until the predetermined criterion is met at some point.
• the determination is continued or repeated until either the predetermined criterion has been met or a predetermined period of time has elapsed since the last self-test (and thus since the first determination) or during orientation the time of day is reached a predetermined further time, and then the self-test is performed.
• a suitable threshold criterion can be used.
• a vector set with threshold values as entries in the vectors that is, to determine whether a threshold curve or threshold area in a higher-dimensional space is exceeded or undershot. If only one amperage is used as a criterion, a single threshold can be used to compare the amperage.
• the residual current device has means for performing a self-test and means for determining whether the current intensity of the current flowing through a current line coupled to the residual current circuit breaker is compatible with a self-test.
• the means for determining are coupled to the means for performing. In this way, it can be decided by the means for performing a self-test, if or when a self-test is performed. Such a decision can in particular be made by a control unit for effecting a self-test, and this can at the same time take on the task of determining in part if it is supplied with a corresponding measurement information.
• means may be provided for measuring a current of the current flowing through the power line and sending signals containing information thereto to the control unit.
• the control unit still comprises a clock or is coupled to such. Then, the control unit may make the appropriate decision to effect a self-test equally of the clock-generated signal and signals generated by the means for measuring.
• FIG. 1 schematically illustrates a residual current circuit breaker as a residual current device according to the invention
• FIG 2 schematically illustrates the feasible by the residual current circuit breaker according to FIG 1 inventive method.
• a fault current circuit breaker can be installed in a line system, so is connected to pairs provided connections by means of power lines, for example, a terminal 14 of a terminal pair of a power line to a first Side is connected and a terminal 16 a and 16 b is connected to a power line to a second side, and wherein in the residual current circuit breaker, the terminal pairs 14 and
• the residual current circuit breaker 16a and 16b are internally connected to each other via a line 18.
• Characteristic of the residual current circuit breaker is that arranged in the line 18, a switch 20 is over which the connection between the terminals 14 and 16a and 16b can be interrupted.
• the embodiment of a residual current circuit breaker for a two-pole system is shown.
• the invention is also applicable to residual current circuit breakers for four-pole systems with three phase lines and a neutral conductor.
• the corresponding elements provided with a dash in FIG. 1 are present.
• summation current transformer 22 This is shown only schematically in FIG. In the present case, its construction and interconnection should be that of a conventional summation current transformer used in a fault current circuit breaker:
• the lines 18 and 18 ' are guided on a primary side by the summation current transformer 22 so that a magnetic field is detected on a secondary side as soon as a fault current occurs. If no fault current occurs, a current flows through the line 18 in a first direction and through the line 18 'in the opposite direction. The magnetic fields provided by these currents in the summation current transformer 22 are equalized so that no magnetic field is detected on the secondary side. If a total current occurs, the current through one of the two lines 18 and 18 'is greater than that through the other of the two lines. Then, a magnetic field is provided on the secondary side, which induces a current in a secondary-side line, and this is detected by an evaluation unit 24.
• the evaluation unit 24 acts on a switching mechanism 26 via which the switches 20, 22 'are opened when the evaluation unit has detected that a fault current is flowing.
• Conventional fault current circuit breakers have a manual test circuit, which in the present case is shown in FIG. 1, even if it is not required in the residual current circuit breaker according to the invention.
• the test circuit has a line 28, which the lines 18 and 18 'with closed switches 20 and 20' miteinender can connect. To make such a connection, a test button is actuated, which closes a switch 30 in the line 28. By the element 32 further elements of the test circuit are symbolized, which should not be described in the present case.
• the summation current switch 22 reacts as if a fault current were flowing.
• the evaluation unit 24 reacts and, via the switching mechanism 26, causes the switches 20 and 20 'to be opened.
• the residual current circuit breaker now comprises a self-test unit 34 as part of a control unit 36.
• This self-test unit 34 should fulfill the same task, which otherwise has the manual test:
• the fault current circuit breaker should be checked for its functionality.
• the self-test unit 34 relieves the operator from performing a regular check.
• the control unit 36 has a timer 38 which causes the self-test unit 34 to perform a self-test.
• the self-test unit 34 may, in analogy to the line 28 with the switch 30, cause the flow around the summation current transformer 22 to flow in such a way that the latter reacts as if a fault current were flowing.
• the self-test unit 34 can also act exclusively on the secondary side of the summation current transformer and thus directly on the evaluation unit 24.
• the timing controller 38 now causes the self-test unit 34 to become active at predetermined times. For example, a self-test can be performed at predetermined time intervals. In the same way, a self-test can be carried out at certain times of the day.
• the conventional residual current circuit breaker 12 which is extended by the control unit 36, extended by further means, namely means for measuring the current through the lines 18 and 18 'and the coupled thereto lines: These means are 40 in FIG designated.
• Corresponding line sections 44 and 44 ' may be part of the extended residual current circuit breaker 10 so that it is connected via external connections 16b and 16' b, but the lines 44 and 44 'may also be deviating from FIG. 1 outside the actual residual current circuit breaker , which are only coupled to the residual current circuit breaker, and then the external terminals of the residual current circuit breaker would be the terminals 16a and 16 'a.
• the voltage drop across the resistors 42 and 42 ' is then measured by a voltage measuring unit 46.
• the resistors With known values for the resistors, it is possible to deduce the current strengths of the current flowing through the line sections 44 and 44 'and thus of the current flowing via the lines 18 and 18'. Instead of using resistors 42 and 42 ', the current can also be measured inductively.
• the measured values are then supplied by the voltage measuring unit 46 to the control unit 36, namely a decision unit 48 present there.
• a decision unit 48 present there.
• the self-test unit 34 then causes the self-test to be performed at the designated time.
• a reclosing device 50 ensures that the contacts 20 and 20 'are closed again.
• the time control 38 determines whether a polling time interval has expired in step S0O, which is carried out continuously or repeatedly.It may be whether a predetermined time has elapsed since the last self-test, or if it has exceeded one At the same time, the measuring circuit 40 (means for measuring) can be active at all times.An activation of the measuring circuit 40 can also take place directly when the interrogation time interval has expired Step S12 checks whether there is a low-load state, ie in the
• step Sl 6 In the case of a connection for an "or” inquiry in step Sl 6, the "Yes” causes the transmission of a "Yes”, and a self-test is performed by the self-test unit 34 according to step S18.
• the "or” query is also assigned a second input, namely, it is checked in step S20 whether a maximum time interval has expired:
• the measuring circuit 40 permanently determines the flow of a current that is regarded as too large, so that the output of the "and" query in step S14 is also constantly answered with "no". Then no self-test would be done. So that it does not come to the permanent omission of a self-test, a maximum time interval is defined, namely since the last self-test. The time interval can also refer to a predetermined time, so that by setting the maximum time interval, a second time is set, and when this is reached, the self-test should be carried out at the latest be. If the question regarding the expiry of the maximum time interval is answered with "yes” in step S20, a "yes” is also forwarded in the "or” query according to step S1, so that the self-test according to step S18 is carried out.
• step S12 determines the timing for performing the self-test: after the expiration of the polling time interval, the self-test is not performed until the answer is "yes.”
• One end has the existence of this relationship only when the maximum time interval has expired ,

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
• Testing Relating To Insulation (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 2008
  • 2008-07-15 DE DE200810033148 patent/DE102008033148B4/de not_active Expired - Fee Related
• 2009
  • 2009-06-17 WO PCT/EP2009/057497 patent/WO2010006868A1/de active Application Filing
  • 2009-06-17 EP EP09779804A patent/EP2301127A1/de not_active Withdrawn
  • 2009-06-17 CN CN200980127420.3A patent/CN102099979B/zh not_active Expired - Fee Related

Non-Patent Citations (1)

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