CA2947094C - Method and device for testing a tap changer of a transformer - Google Patents
Method and device for testing a tap changer of a transformer Download PDFInfo
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- CA2947094C CA2947094C CA2947094A CA2947094A CA2947094C CA 2947094 C CA2947094 C CA 2947094C CA 2947094 A CA2947094 A CA 2947094A CA 2947094 A CA2947094 A CA 2947094A CA 2947094 C CA2947094 C CA 2947094C
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- transformer
- tap changer
- resistance value
- winding
- test signal
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/327—Testing of circuit interrupters, switches or circuit-breakers
- G01R31/3271—Testing of circuit interrupters, switches or circuit-breakers of high voltage or medium voltage devices
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/327—Testing of circuit interrupters, switches or circuit-breakers
- G01R31/3271—Testing of circuit interrupters, switches or circuit-breakers of high voltage or medium voltage devices
- G01R31/3272—Apparatus, systems or circuits therefor
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/327—Testing of circuit interrupters, switches or circuit-breakers
- G01R31/3271—Testing of circuit interrupters, switches or circuit-breakers of high voltage or medium voltage devices
- G01R31/3272—Apparatus, systems or circuits therefor
- G01R31/3274—Details related to measuring, e.g. sensing, displaying or computing; Measuring of variables related to the contact pieces, e.g. wear, position or resistance
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/327—Testing of circuit interrupters, switches or circuit-breakers
- G01R31/333—Testing of the switching capacity of high-voltage circuit-breakers ; Testing of breaking capacity or related variables, e.g. post arc current or transient recovery voltage
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/62—Testing of transformers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H9/00—Details of switching devices, not covered by groups H01H1/00 - H01H7/00
- H01H9/0005—Tap change devices
- H01H2009/0061—Monitoring tap change switching devices
Abstract
The following steps are performed in order to test a tap changer (20) of a transformer (5; 6) which tap changer is designed to change a transmission ratio of the transformer (5; 6): Generating a test signal which is supplied to a winding (1-3; 10) of the transformer (5; 6) and to the tap changer (20). Actuating the tap changer (20) in order to change the transmission ratio. Determining an electrical resistance value of the transformer (5; 6) during the step of actuating the tap changer (20) depending on the test signal.
Description
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27003W0 HJB/sr 1 Method and device for testing a tap changer of a transformer The present invention relates to a method and a device for testing a tap changer of a transformer, in particular a power transformer.
Electrical power transformers, which are for example used for energy generation, energy transfer, energy distribution or for industrial applications and are designed for outputs greater than 1 MW, often comprise so-called tap changers in order to be able to adapt the transmission ratio of the respective transformer, for example to certain load conditions. Tap changers, which can also be switched during the operation of the transformer or under load, i.e.
without interrupting the operation, are often also designated as on-load tap changers (OLTC). To this end, the winding of the transformer is designed as a so-called bank winding, wherein taps or tappings of this bank winding are guided to the tap changer which then switches over from one tap to another tap during the operation of the transformer in order to thereby change the transmission ratio of the transformer.
Since the windings of a transformer respectively constitute a large inductivity, a switching process between different transmission ratios cannot be implemented without problems since it is not possible to easily interrupt the current flow through a winding. A tap changer is thus designed such that the current can flow through the winding at any time. To this end, the tap changer often switches over the current, which flows through the winding, by means of resistors in order to thereby change the transmission ratio. The switching process must be performed quickly in order to avoid excessive heating of the resistors. Regular testing of each tap changer is recommended due to the complex and thus error-prone mechanics of the tap changers.
The object of the present invention is thus to improve the testing of a tap changer compared to the prior art.
According to the invention, this object is achieved by a method for testing a tap
27003W0 HJB/sr 1 Method and device for testing a tap changer of a transformer The present invention relates to a method and a device for testing a tap changer of a transformer, in particular a power transformer.
Electrical power transformers, which are for example used for energy generation, energy transfer, energy distribution or for industrial applications and are designed for outputs greater than 1 MW, often comprise so-called tap changers in order to be able to adapt the transmission ratio of the respective transformer, for example to certain load conditions. Tap changers, which can also be switched during the operation of the transformer or under load, i.e.
without interrupting the operation, are often also designated as on-load tap changers (OLTC). To this end, the winding of the transformer is designed as a so-called bank winding, wherein taps or tappings of this bank winding are guided to the tap changer which then switches over from one tap to another tap during the operation of the transformer in order to thereby change the transmission ratio of the transformer.
Since the windings of a transformer respectively constitute a large inductivity, a switching process between different transmission ratios cannot be implemented without problems since it is not possible to easily interrupt the current flow through a winding. A tap changer is thus designed such that the current can flow through the winding at any time. To this end, the tap changer often switches over the current, which flows through the winding, by means of resistors in order to thereby change the transmission ratio. The switching process must be performed quickly in order to avoid excessive heating of the resistors. Regular testing of each tap changer is recommended due to the complex and thus error-prone mechanics of the tap changers.
The object of the present invention is thus to improve the testing of a tap changer compared to the prior art.
According to the invention, this object is achieved by a method for testing a tap
2 changer of a transformer, wherein the tap changer is designed to change a transmission ratio of the transformer, wherein the method comprises the following steps:
generating a test signal which is supplied to a winding of the transformer and to the tap changer, actuating the tap changer in order to change the transmission ratio, and determining an electrical resistance value of the winding of the transformer during the step of actuating the tap changer depending on the test signal. This object may also be achieved with the device for testing a tap changer of a transformer, wherein the tap changer is designed to change a transmission ratio of the transformer, wherein the device comprises test signal generation means, measuring means and control means, wherein the device is designed to supply a test signal to a winding of the transformer and to the tap changer by means of the test signal generation means and wherein the device is designed to determine an electrical resistance value of the winding of the transformer by means of the measuring means and the control means during an actuation of the tap changer depending on the test signal.
A method for testing a tap changer of a transformer is prepared within the context of the present invention. In this regard, the tap changer is designed to change (under load) a transmission ratio of the transformer. The method according to the invention comprises the following steps:
= Generating a test signal which is supplied to a winding of the transformer and to the tap changer. The test signal may be, for example an electric current which flows through the winding and the tap changer arranged in series with the winding and is typically between a few amperes and approximately 100 amperes strong. The test signal may also be an electric voltage which is applied to the winding and/or to the tap changer such that an electric current results which flows through the series circuit from the winding and the tap changer.
= Actuating the tap changer, wherein the transmission ratio of the transformer is changed when actuating the tap changer.
= Determining a transient electrical resistance value of the transformer during the actuation of the tap changer, wherein the electrical resistance value is dependent on the test signal.
In order to test the tap changer by means of the electrical resistance value or more accurately by means of a time curve of the resistance value, at least one measurement [i 2a variable, for example a current flowing through the winding and the tap changer connected in series and/or a voltage falling at the winding is in particular measured, wherein the at least one measurement variable (and thus the resistance value) changes by actuating the tap changer depending on the test signal generated. This at least one measurement variable is either itself the resistance value or comprises one or a plurality of measurement variables (e.g. current and voltage) from which the resistance value can be determined.
The time curve of the at least one measurement variable and thus of the resistance value can for example be determined by the at least one measurement variable being continually determined during a predetermined time interval or at determined time periods within this time interval (e.g. 100 ms). In this 27003W0 HJB/sr 3 regard, the time interval in particular begins directly before or shortly after the beginning of the actuation of the tap changer and ends after the transmission ratio has been changed by the tap changer or after the most abrupt changes of the measurement variable owing to the actuation of the tap changer or the switching process have abated.
By means of the transient (i.e. non-stationary) resistance value, which is determined during the actuation of the tap changer, or by means of the time curve of the resistance value, the decision regarding whether or not the tap changer is operating correctly, can be made in an improved and simpler manner than is the case according to the prior art. In this regard, the determined resistance value and the time curve of the resistance value can in particular be evaluated by means of historical data (e.g. previously determined resistance values or previously determined time curves of resistance values in the case of demonstrably correctly operating transformers) in order to decide whether the tap changer is currently operating correctly.
According to a preferred embodiment according to the invention, the transformer may be a multi-phase transformer (e.g. a three-phase alternating current transformer). In the case of a multi-phase transformer, a separate tap changer is present for each phase of the transformer which is designed to change (under load) a transmission ratio of the transformer. In order to test the tap changers, a test signal is respectively generated for each phase of the transformer simultaneously. This test signal is, for each phase, supplied to a winding of the transformer assigned to the respective phase and to the tap changer assigned to this winding. If the test signals are respectively a current, a current is for example generated for each phase of the transformer simultaneously which flows through the winding assigned to the respective phase and through the tap changer assigned to the winding, said tap changer being arranged in series with the respective winding. If the test signals are respectively a voltage, a voltage is, for example for each phase of the transformer, simultaneously applied to the winding assigned to this phase in order to thereby generate a current through this winding and the assigned tap changer. The tap changers are actuated, wherein the transmission ratio is 27003W0 HJB/sr 4 changed with each actuation. In this regard, the tap changers should all be actuated simultaneously. During the actuation of the tap changers, a transient electrical resistance value or a time curve of this resistance value is determined for each winding assigned to the respective tap changer, said resistance value changes depending on the test signal during the switching process. The determining of the respective resistance value takes place in particular in turn with at least one measurement variable, as was previously described. In this regard, a measurement variable may be an electric current which flows through one of the windings and the tap changer assigned to this winding and arranged in series with this winding. Another measurement variable may be an electric voltage which falls at one of the windings.
By means of the resistance value determined for the respective phase, it can be decided whether the respective tap changer of the multi-phase transformer is operating correctly. In this regard, the resistance value determined for the respective phase can be compared with a corresponding resistance value in the case of a correctly operating tap changer.
The test signals can be generated for each phase such that the test signals comprise the same value, whereby the resistance values determined for different phases are advantageously comparable with each other.
In the case of a three-phase transformer with a star point connection, which preferably comprises a Y or a Z winding, all three-phases can be tested simultaneously. To this end, a current can be impressed as the test signal, which flows, in the case of two phases, into the winding (i.e. the current is impressed on the winding at the end facing away from the star point) and flows, in the case of one phase, from the winding (i.e. the current is removed from the winding at the end facing away from the star point). If the three currents are identical in terms of value, a fourth current additionally flows out (i.e. it is removed from the winding at the end facing away from the star point).
Both in the case of a multi-phase transformer and in the case of a single-phase transformer, the test signal can be a direct current signal, i.e. an electric direct 27003W0 HJB/sr 5 current.
As was previously at least partially described, the electrical resistance value can be determined by means of electric measurement variables. If a measurement variable is the electric current which flows through the respective winding and the tap changer assigned to this winding and if the other measurement variable is the electric voltage which falls at the respective winding, the electrical resistance value can then be calculated depending on the voltage and the current (in particular as a quotient from the voltage and the current). This resistance value may be an ohmic resistance value or direct current resistance value or an impedance value or alternating current resistance.
According to the invention, the at least measurement variable may also be .. other electrical variables, such as for example the electrical output or the electric energy which is received by the respective winding or delivered by the same. It is also possible in this case for the electrical resistance value to be determined proceeding from the at least one measurement variable.
According to the invention, it is, on the one hand, possible to automatically evaluate the determined electrical resistance value in order to test the tap changer or in order to decide whether the respective tap changer is operating correctly. On the other hand, it is, however, also possible according to the invention to output the respective electrical resistance value, for example in order to be able to allow an expert to decide by means of the output whether the respective tap changer is operating correctly.
In particular, if determining and/or identifying the respective electrical resistance value comprises determining and/or identifying a time curve of the respective .. electrical resistance value, outputting the respective electrical resistance value advantageously comprises illustrating the time curve of the respective electrical resistance value.
In order to test the respective tap changer, a plurality of determined time curves 27003W0 HJB/sr 6 of the electrical resistance value, which are determined and/or identified with a plurality of actuations of the respective tap changer, can be automatically illustrated in a temporally-superimposed manner. The illustration of the curves takes place in this regard in particular via a display or a screen. However, it is also possible to print out the curves on a printer for the illustration thereof or to illustrate them on other media. It is in particular understood by the temporally-superimposed illustration of the curves that a temporal end of each of the illustrated curves is plotted after all temporal beginnings of the illustrated curves. The illustrated (temporally-superimposed) curves of the electrical resistance values can also be evaluated by means of historical data (e.g.
previously determined curves of the resistance value).
In the case of the temporally-superimposed illustration of the curves of the respectively determined electrical resistance values, there is, on the one hand, the possibility to plot the curves as congruently as possible such that for example two identical curves are illustrated precisely over each other.
Another possibility according to the invention is to plot the curves (slightly) offset such that for example two identical curves can be distinguished. In this regard, the curves can be illustrated offset either in the direction of the time axis and/or perpendicular to the time axis.
For the temporally-superimposed illustration of the curves, time periods of the curves corresponding to each other are in particular illustrated in a temporally-superimposed manner. In this regard, the respectively corresponding time period or the respectively corresponding time interval of the respective curve can begin shortly before or shortly after the respective actuation of the tap changer and can end after the end of the performance of the switching to a new transmission ratio. The respective time period of the respective curve can for example be 100 ms of the respective switching process.
The length of the time interval, during which the curve of the respective resistance value is determined, can be selected such that the transformer reaches saturation after switching to the new transmission ratio such that the determined resistance value also comprises the resistance of the winding.
27003W0 HJB/sr 7 In the context of the present invention, a device for testing a tap changer of a transformer is also prepared. In this regard, the tap changer is designed to change (under load or during operation) a transmission ratio of the transformer.
The device comprises test signal generation means, measuring means and control means. By means of the test signal generation means and the control means, the device generates a test signal which is supplied to a winding of the transformer and to the tap changer. By means of the measuring means and the control means, the device is capable of determining and/or identifying an electrical resistance value of the transformer during an actuation of the tap changer depending on the test signal.
The advantages of the device according to the invention correspond substantially to the advantages of the method according to the invention which were previously explained in detail such that they will not be repeated here.
According to an embodiment according to the invention, the transformer may be a multi-phase transformer, wherein a separate tap changer is present for each phase of the transformer, said tap changer is designed to change (under load) a transmission ratio of the transformer. According to this embodiment according to the invention, the device is thus designed to test a tap changer or the tap changers of a multi-phase transformer. Furthermore, the device is designed to simultaneously generate respectively one test signal for each phase of the transformer by means of the test signal generation means and to supply these test signals respectively (i.e. respectively one of these test signals) to a winding of the transformer assigned to the respective phase or to the tap changer assigned to this winding. The device is capable of determining an electrical resistance value for each winding by means of the measuring means and the control means during an actuation of the tap changer depending on the test signal.
The advantages of this embodiment according to the invention correspond substantially to the advantages of the corresponding embodiment of the method according to the invention which were previously explained in detail 27003W0 HJB/sr 8 such that they will not be repeated here.
The device in particular comprises a display and is designed such that the device illustrates the resistance value or time curves of the resistance value on this display by means of the control means.
The interpretation of the determined resistance value is simplified in comparison to the prior art by means of outputting the electrical resistance value and in particular by means of the graphic illustration of the temporally-superimposed curves of the electrical resistance value for the respective tap changer. As a result, the testing of the tap changer is ultimately also simplified.
The present invention can in particular be used for testing tap changers of power transformers. The present invention is of course not limited to this preferred field of application since the invention can for example also be used to test tap changers of transformers which are not considered power transformers.
The invention is described in detail below by means of preferred embodiments according to the invention with reference to the figures.
A plurality of time curves of an electric current is illustrated in Fig. 1 in the case of actuating a tap changer of a transformer.
Only certain time curves of those illustrated in Fig. 1 are illustrated in Figures 2 to 4.
The time curves of an electric current in the case of actuating a tap changer of a transformer are not illustrated in a temporally-superimposed manner in Fig.
5, but rather they are illustrated chronologically.
A transformer with tap changer is illustrated together with a device according to the invention in Fig. 6.
= CA 02947094 2016-10-26 27003W0 HJB/sr 9 A multi-phase transformer is illustrated together with a device according to the invention in Fig. 7.
A device according to the invention is schematically illustrated in Fig. 8.
Although one electric current is respectively illustrated in the following figures by way of example both as a test signal and as a measurement variable, it should be explicitly noted that according to the invention a voltage can also be applied as the test signal and/or that a voltage, an electrical resistance, an impedance, an output, energy etc. can also be used or determined as a measurement variable in order to identify an electrical resistance value of the transformer depending on the measurement variable.
A plurality of time curves 41, 42 of an electric current are illustrated in a temporally-superimposed manner in Fig. 1, wherein each of the curves 41, 42 is determined in the case of the actuation of a tap changer of a transformer.
The electric current, the curve of which is determined, flows through the winding and the tap changer arranged in series with the winding. A time period is respectively illustrated for each of the curves which begins at a first time point to and ends at a second time point ti. In this regard, the first time point to comes shortly after the beginning of the actuation of the tap changer and the second time point ti comes after the end of the switching process of the tap changer.
If, in addition to the electric current, a voltage falling via the winding is also determined over time, a time curve of an electrical resistance value can be determined by means of a quotient from the voltage and the current. In this case, the time curves of the resistance value are thus illustrated in a temporally-superimposed manner, as the time curves of the current are illustrated in Fig. 1 (and Figures 2 to 4).
In the present case, the winding comprises eleven taps or tappings between which the tap changer can be switched, as is explained more precisely in Fig. 6. The curves labelled with the reference numeral 41 respectively show one of ten current curves which are determined when the tap changer switches 27003W0 HJB/sr 10 upwards, whereby the number of the effective coils of winding is reduced. In a similar manner, the curves labelled with the reference numeral 42 respectively show one of ten current curves which are determined when the tap changer switches downwards, whereby the number of the effective coils of the winding is increased.
As illustrated in Fig. 6, there are left-hand or odd taps 13 and right-hand or even taps 12 of the winding 10. Only the current curves 41, 42 in the case of even switching processes are illustrated in Fig. 2 by eliminating the current curves in the case of odd switching processes by means of filters. An even switching process is then present when switching takes place to an even or right-hand tap 12. In this regard, switching can take place to an even or right-hand tap 12 both in the case of downwards switching and in the case of upwards switching. In other words, the current curves labelled with the reference numeral 41 in Fig. 2 show five even switching processes in the case of downwards switching, while the current curves labelled with the reference numeral 42 in Fig. 2 show five even switching processes in the case of upwards switching.
In contrast, only the current curves 41, 42 in the case of odd switching processes are illustrated in Fig. 3 by eliminating the current curves in the case of even switching processes by means of filters. An odd switching process is then present when switching takes place to an odd or left-hand tap 13 (see Fig. 6) Like in the case of even switching processes, in the case of odd switching processes, switching can take place to an odd or left-hand tap 13 both in the case of downwards switching and in the case of upwards switching.
In other words, the current curves labelled with the reference numeral 41 in Fig. 3 show five odd switching processes in the case of downwards switching, while the current curves labelled with the reference numeral 42 in Fig. 3 show five odd switching processes in the case of upwards switching.
Only the ten current curves 41 in the case of even switching processes are illustrated in Fig. 4 such that the ten current curves 42 in the case of odd switching processes (see Fig. 1) are not illustrated since they have been filtered = CA 02947094 2016-10-26 27003W0 HJB/sr 11 out.
The 20 current curves 41, 42 from Fig. 1 are illustrated in Fig. 5 chronologically side by side. In this connection, a time point (e.g. t3 or t6), at which a current curve 41, 42 ends, corresponds to a time point at which a current curve illustrated adjacent thereto begins. In other words, the current curves illustrated in Fig. 5 are not illustrated in a temporally-superimposed manner.
A transformer 6 with a tap changer 20 and a device 30 according to the invention for testing the tap changer 20 are illustrated in Fig. 6.
The transformer 6 comprises a winding 10 which has a plurality of taps or tappings 12, 13. The tap changer 20 comprises two tap selectors 14, 15. In this regard, the one tap selector 14 is connected to one of the right-hand or even taps 12 and the other tap selector 15 is connected to one of the left-hand or odd taps 13. Furthermore, the tap changer 20 comprises a first connection 21 and a first resistor 22 which are assigned to the tap selector 15 as well as a second connection 24 and a second resistor 23 which are assigned to the tap selector 14. In the case of the condition illustrated in Fig. 6, a current I
flows at connection 11 into the winding 10 and flows out from the winding 10 at the tap 13 which is in contact with the tap selector 15.
In order to now change the transmission ratio of the transformer 6, a switch of the tap changer 20 is switched from connection 21 to connection 24. The switch 25 here contacts in a first step both the first connection 21 and the first resistor 22 such that the current I flows through the first resistor 22 if the switch 25 loses the contact to the first connection 21 in the second step. In the third step, the switch 25 contacts both the first resistor 22 and the second resistor 23 such that the current I flows both via the first resistor 22 and via the second resistor 23 and thus both via the tap selector 15 and the corresponding tap 13 and via the tap selector 14 and the corresponding taps 12. If the switch 25 is switched further, the switch 25 loses the contact with the first resistor 22 in the fourth step such that the current I flows in the fourth step only via the second resistor 23 and the tap selector 14 and the corresponding tap 12. If the switch 27003W0 HJB/sr 12 25 is switched further, the switch 25 contacts the second connection 24 in the fifth step such that the second resistor 23 is virtually short-circuited. The current I flows via the second connection 24 as well as the tap selector 14 and the associated tap 12 such that the transmission ratio of the transformer 6 changes correspondingly. If the switch 25 is switched further, the switch 25 loses the contact to the second resistor 23 in the sixth and final step, whereby the switching process or the actuation of the tap changer 20 for changing the transmission ratio of the transformer 6 has finally ended.
As soon as the tap selector 15 is switched in a currentless manner (i.e. with the fourth step), the tap selector can be connected to another left-hand or odd tap 13. In order to once again change the transmission ratio of the transformer 6, the switch 25 is switched in a similar manner as previously described from the second connection 24 to the first connection 21.
In order to test the tap changer 20, the device 30 according to the invention is present which has a current source 31 and an ammeter 32. The current I is generated by means of the current source 31 which flows through the winding 10 and the tap changer 20 arranged in series with the winding 10. A time curve of the current I flowing through the winding 10 and the tap changer 20 is in particular determined during the switching over of the tap changer 20 with the corresponding measuring device 9 (see Fig. 8) of the device 30 according to the invention.
If the measuring device 9 (see Fig. 8) is also designed to determine a time curve of the voltage falling via the winding 10, the time curve of the electrical resistance value of the winding 10 can be determined by the controller 7 (see Fig. 8) of the device 30 by dividing, for each point in time, the voltage determined at this point in time by the current determined at this point in time.
.. The device 30 according to the invention is then capable of illustrating, in a temporally-superimposed manner, time curves of the resistance values which have been determined and identified during the switching processes of the tap changer 20.
= CA 02947094 2016-10-26 27003W0 HJB/sr 13 A multi-phase transformer 5 is illustrated in Fig. 7 which has three phases with respectively one winding 1-3 in a Y-interconnection. In this regard, each phase or winding 1-3 has a tap changer 20 (not illustrated in Fig. 7) in order to change the transmission ratio of the transformer 5 in the same manner as was previously described with regard to Fig. 6.
In order to test the tap changer, the device 30 according to the invention generates a first direct current Ii which is supplied to the end of the first winding 1 facing away from the star point 4 and a second direct current 12 which is, on the one hand, taken away from the end of the third winding 3 facing away from the star point 4 and, on the other hand, is supplied to the end of the second winding 2 facing away from the star point 4. It can be discerned that the first direct current 11 also flows away from the star point 4 to the device 30. In other words, the test signals or direct currents 11, 12, which are supplied to each winding 1-3, comprise the same value.
The time curves of the resistance values of the three windings 1-3 are determined, while the tap changers are repeatedly switched in order to change the transmission ratio of the multi-phase transformer 5. A plurality of determined or identified resistance value curves are illustrated in a temporally-superimposed manner for each tap changer in order to test the correct operation of the tap changers.
A further embodiment of the device 30 according to the invention is schematically illustrated in Fig. 8. In addition to a current source 31 which corresponds to the test signal generation means, the device 30 comprises a controller 7, a display 8 and a measuring means 9 by means of which a time curve of the electrical resistance value can be determined or identified. The determined or identified time curves of the resistance value are illustrated on the display 8 in a temporally-superimposed manner.
=
27003W0 HJB/sr 14 LIST OF REFERENCE NUMERALS
1-3 Winding 4 Star point 5 Three-phase alternating current transformer 6 Transformer 7 Controller 8 Display 9 Measuring device 10 Winding 14,15 Tap selectors 12, 13 Taps Tap changer 15 11, 21, 24 Connection 22, 23 Resistor Device 31 Current source 32 Ammeter 20 41 Current curve in the case of downwards switching 42 Current curve in the case of upwards switching 1,11,12 Direct current Time tx Time point
generating a test signal which is supplied to a winding of the transformer and to the tap changer, actuating the tap changer in order to change the transmission ratio, and determining an electrical resistance value of the winding of the transformer during the step of actuating the tap changer depending on the test signal. This object may also be achieved with the device for testing a tap changer of a transformer, wherein the tap changer is designed to change a transmission ratio of the transformer, wherein the device comprises test signal generation means, measuring means and control means, wherein the device is designed to supply a test signal to a winding of the transformer and to the tap changer by means of the test signal generation means and wherein the device is designed to determine an electrical resistance value of the winding of the transformer by means of the measuring means and the control means during an actuation of the tap changer depending on the test signal.
A method for testing a tap changer of a transformer is prepared within the context of the present invention. In this regard, the tap changer is designed to change (under load) a transmission ratio of the transformer. The method according to the invention comprises the following steps:
= Generating a test signal which is supplied to a winding of the transformer and to the tap changer. The test signal may be, for example an electric current which flows through the winding and the tap changer arranged in series with the winding and is typically between a few amperes and approximately 100 amperes strong. The test signal may also be an electric voltage which is applied to the winding and/or to the tap changer such that an electric current results which flows through the series circuit from the winding and the tap changer.
= Actuating the tap changer, wherein the transmission ratio of the transformer is changed when actuating the tap changer.
= Determining a transient electrical resistance value of the transformer during the actuation of the tap changer, wherein the electrical resistance value is dependent on the test signal.
In order to test the tap changer by means of the electrical resistance value or more accurately by means of a time curve of the resistance value, at least one measurement [i 2a variable, for example a current flowing through the winding and the tap changer connected in series and/or a voltage falling at the winding is in particular measured, wherein the at least one measurement variable (and thus the resistance value) changes by actuating the tap changer depending on the test signal generated. This at least one measurement variable is either itself the resistance value or comprises one or a plurality of measurement variables (e.g. current and voltage) from which the resistance value can be determined.
The time curve of the at least one measurement variable and thus of the resistance value can for example be determined by the at least one measurement variable being continually determined during a predetermined time interval or at determined time periods within this time interval (e.g. 100 ms). In this 27003W0 HJB/sr 3 regard, the time interval in particular begins directly before or shortly after the beginning of the actuation of the tap changer and ends after the transmission ratio has been changed by the tap changer or after the most abrupt changes of the measurement variable owing to the actuation of the tap changer or the switching process have abated.
By means of the transient (i.e. non-stationary) resistance value, which is determined during the actuation of the tap changer, or by means of the time curve of the resistance value, the decision regarding whether or not the tap changer is operating correctly, can be made in an improved and simpler manner than is the case according to the prior art. In this regard, the determined resistance value and the time curve of the resistance value can in particular be evaluated by means of historical data (e.g. previously determined resistance values or previously determined time curves of resistance values in the case of demonstrably correctly operating transformers) in order to decide whether the tap changer is currently operating correctly.
According to a preferred embodiment according to the invention, the transformer may be a multi-phase transformer (e.g. a three-phase alternating current transformer). In the case of a multi-phase transformer, a separate tap changer is present for each phase of the transformer which is designed to change (under load) a transmission ratio of the transformer. In order to test the tap changers, a test signal is respectively generated for each phase of the transformer simultaneously. This test signal is, for each phase, supplied to a winding of the transformer assigned to the respective phase and to the tap changer assigned to this winding. If the test signals are respectively a current, a current is for example generated for each phase of the transformer simultaneously which flows through the winding assigned to the respective phase and through the tap changer assigned to the winding, said tap changer being arranged in series with the respective winding. If the test signals are respectively a voltage, a voltage is, for example for each phase of the transformer, simultaneously applied to the winding assigned to this phase in order to thereby generate a current through this winding and the assigned tap changer. The tap changers are actuated, wherein the transmission ratio is 27003W0 HJB/sr 4 changed with each actuation. In this regard, the tap changers should all be actuated simultaneously. During the actuation of the tap changers, a transient electrical resistance value or a time curve of this resistance value is determined for each winding assigned to the respective tap changer, said resistance value changes depending on the test signal during the switching process. The determining of the respective resistance value takes place in particular in turn with at least one measurement variable, as was previously described. In this regard, a measurement variable may be an electric current which flows through one of the windings and the tap changer assigned to this winding and arranged in series with this winding. Another measurement variable may be an electric voltage which falls at one of the windings.
By means of the resistance value determined for the respective phase, it can be decided whether the respective tap changer of the multi-phase transformer is operating correctly. In this regard, the resistance value determined for the respective phase can be compared with a corresponding resistance value in the case of a correctly operating tap changer.
The test signals can be generated for each phase such that the test signals comprise the same value, whereby the resistance values determined for different phases are advantageously comparable with each other.
In the case of a three-phase transformer with a star point connection, which preferably comprises a Y or a Z winding, all three-phases can be tested simultaneously. To this end, a current can be impressed as the test signal, which flows, in the case of two phases, into the winding (i.e. the current is impressed on the winding at the end facing away from the star point) and flows, in the case of one phase, from the winding (i.e. the current is removed from the winding at the end facing away from the star point). If the three currents are identical in terms of value, a fourth current additionally flows out (i.e. it is removed from the winding at the end facing away from the star point).
Both in the case of a multi-phase transformer and in the case of a single-phase transformer, the test signal can be a direct current signal, i.e. an electric direct 27003W0 HJB/sr 5 current.
As was previously at least partially described, the electrical resistance value can be determined by means of electric measurement variables. If a measurement variable is the electric current which flows through the respective winding and the tap changer assigned to this winding and if the other measurement variable is the electric voltage which falls at the respective winding, the electrical resistance value can then be calculated depending on the voltage and the current (in particular as a quotient from the voltage and the current). This resistance value may be an ohmic resistance value or direct current resistance value or an impedance value or alternating current resistance.
According to the invention, the at least measurement variable may also be .. other electrical variables, such as for example the electrical output or the electric energy which is received by the respective winding or delivered by the same. It is also possible in this case for the electrical resistance value to be determined proceeding from the at least one measurement variable.
According to the invention, it is, on the one hand, possible to automatically evaluate the determined electrical resistance value in order to test the tap changer or in order to decide whether the respective tap changer is operating correctly. On the other hand, it is, however, also possible according to the invention to output the respective electrical resistance value, for example in order to be able to allow an expert to decide by means of the output whether the respective tap changer is operating correctly.
In particular, if determining and/or identifying the respective electrical resistance value comprises determining and/or identifying a time curve of the respective .. electrical resistance value, outputting the respective electrical resistance value advantageously comprises illustrating the time curve of the respective electrical resistance value.
In order to test the respective tap changer, a plurality of determined time curves 27003W0 HJB/sr 6 of the electrical resistance value, which are determined and/or identified with a plurality of actuations of the respective tap changer, can be automatically illustrated in a temporally-superimposed manner. The illustration of the curves takes place in this regard in particular via a display or a screen. However, it is also possible to print out the curves on a printer for the illustration thereof or to illustrate them on other media. It is in particular understood by the temporally-superimposed illustration of the curves that a temporal end of each of the illustrated curves is plotted after all temporal beginnings of the illustrated curves. The illustrated (temporally-superimposed) curves of the electrical resistance values can also be evaluated by means of historical data (e.g.
previously determined curves of the resistance value).
In the case of the temporally-superimposed illustration of the curves of the respectively determined electrical resistance values, there is, on the one hand, the possibility to plot the curves as congruently as possible such that for example two identical curves are illustrated precisely over each other.
Another possibility according to the invention is to plot the curves (slightly) offset such that for example two identical curves can be distinguished. In this regard, the curves can be illustrated offset either in the direction of the time axis and/or perpendicular to the time axis.
For the temporally-superimposed illustration of the curves, time periods of the curves corresponding to each other are in particular illustrated in a temporally-superimposed manner. In this regard, the respectively corresponding time period or the respectively corresponding time interval of the respective curve can begin shortly before or shortly after the respective actuation of the tap changer and can end after the end of the performance of the switching to a new transmission ratio. The respective time period of the respective curve can for example be 100 ms of the respective switching process.
The length of the time interval, during which the curve of the respective resistance value is determined, can be selected such that the transformer reaches saturation after switching to the new transmission ratio such that the determined resistance value also comprises the resistance of the winding.
27003W0 HJB/sr 7 In the context of the present invention, a device for testing a tap changer of a transformer is also prepared. In this regard, the tap changer is designed to change (under load or during operation) a transmission ratio of the transformer.
The device comprises test signal generation means, measuring means and control means. By means of the test signal generation means and the control means, the device generates a test signal which is supplied to a winding of the transformer and to the tap changer. By means of the measuring means and the control means, the device is capable of determining and/or identifying an electrical resistance value of the transformer during an actuation of the tap changer depending on the test signal.
The advantages of the device according to the invention correspond substantially to the advantages of the method according to the invention which were previously explained in detail such that they will not be repeated here.
According to an embodiment according to the invention, the transformer may be a multi-phase transformer, wherein a separate tap changer is present for each phase of the transformer, said tap changer is designed to change (under load) a transmission ratio of the transformer. According to this embodiment according to the invention, the device is thus designed to test a tap changer or the tap changers of a multi-phase transformer. Furthermore, the device is designed to simultaneously generate respectively one test signal for each phase of the transformer by means of the test signal generation means and to supply these test signals respectively (i.e. respectively one of these test signals) to a winding of the transformer assigned to the respective phase or to the tap changer assigned to this winding. The device is capable of determining an electrical resistance value for each winding by means of the measuring means and the control means during an actuation of the tap changer depending on the test signal.
The advantages of this embodiment according to the invention correspond substantially to the advantages of the corresponding embodiment of the method according to the invention which were previously explained in detail 27003W0 HJB/sr 8 such that they will not be repeated here.
The device in particular comprises a display and is designed such that the device illustrates the resistance value or time curves of the resistance value on this display by means of the control means.
The interpretation of the determined resistance value is simplified in comparison to the prior art by means of outputting the electrical resistance value and in particular by means of the graphic illustration of the temporally-superimposed curves of the electrical resistance value for the respective tap changer. As a result, the testing of the tap changer is ultimately also simplified.
The present invention can in particular be used for testing tap changers of power transformers. The present invention is of course not limited to this preferred field of application since the invention can for example also be used to test tap changers of transformers which are not considered power transformers.
The invention is described in detail below by means of preferred embodiments according to the invention with reference to the figures.
A plurality of time curves of an electric current is illustrated in Fig. 1 in the case of actuating a tap changer of a transformer.
Only certain time curves of those illustrated in Fig. 1 are illustrated in Figures 2 to 4.
The time curves of an electric current in the case of actuating a tap changer of a transformer are not illustrated in a temporally-superimposed manner in Fig.
5, but rather they are illustrated chronologically.
A transformer with tap changer is illustrated together with a device according to the invention in Fig. 6.
= CA 02947094 2016-10-26 27003W0 HJB/sr 9 A multi-phase transformer is illustrated together with a device according to the invention in Fig. 7.
A device according to the invention is schematically illustrated in Fig. 8.
Although one electric current is respectively illustrated in the following figures by way of example both as a test signal and as a measurement variable, it should be explicitly noted that according to the invention a voltage can also be applied as the test signal and/or that a voltage, an electrical resistance, an impedance, an output, energy etc. can also be used or determined as a measurement variable in order to identify an electrical resistance value of the transformer depending on the measurement variable.
A plurality of time curves 41, 42 of an electric current are illustrated in a temporally-superimposed manner in Fig. 1, wherein each of the curves 41, 42 is determined in the case of the actuation of a tap changer of a transformer.
The electric current, the curve of which is determined, flows through the winding and the tap changer arranged in series with the winding. A time period is respectively illustrated for each of the curves which begins at a first time point to and ends at a second time point ti. In this regard, the first time point to comes shortly after the beginning of the actuation of the tap changer and the second time point ti comes after the end of the switching process of the tap changer.
If, in addition to the electric current, a voltage falling via the winding is also determined over time, a time curve of an electrical resistance value can be determined by means of a quotient from the voltage and the current. In this case, the time curves of the resistance value are thus illustrated in a temporally-superimposed manner, as the time curves of the current are illustrated in Fig. 1 (and Figures 2 to 4).
In the present case, the winding comprises eleven taps or tappings between which the tap changer can be switched, as is explained more precisely in Fig. 6. The curves labelled with the reference numeral 41 respectively show one of ten current curves which are determined when the tap changer switches 27003W0 HJB/sr 10 upwards, whereby the number of the effective coils of winding is reduced. In a similar manner, the curves labelled with the reference numeral 42 respectively show one of ten current curves which are determined when the tap changer switches downwards, whereby the number of the effective coils of the winding is increased.
As illustrated in Fig. 6, there are left-hand or odd taps 13 and right-hand or even taps 12 of the winding 10. Only the current curves 41, 42 in the case of even switching processes are illustrated in Fig. 2 by eliminating the current curves in the case of odd switching processes by means of filters. An even switching process is then present when switching takes place to an even or right-hand tap 12. In this regard, switching can take place to an even or right-hand tap 12 both in the case of downwards switching and in the case of upwards switching. In other words, the current curves labelled with the reference numeral 41 in Fig. 2 show five even switching processes in the case of downwards switching, while the current curves labelled with the reference numeral 42 in Fig. 2 show five even switching processes in the case of upwards switching.
In contrast, only the current curves 41, 42 in the case of odd switching processes are illustrated in Fig. 3 by eliminating the current curves in the case of even switching processes by means of filters. An odd switching process is then present when switching takes place to an odd or left-hand tap 13 (see Fig. 6) Like in the case of even switching processes, in the case of odd switching processes, switching can take place to an odd or left-hand tap 13 both in the case of downwards switching and in the case of upwards switching.
In other words, the current curves labelled with the reference numeral 41 in Fig. 3 show five odd switching processes in the case of downwards switching, while the current curves labelled with the reference numeral 42 in Fig. 3 show five odd switching processes in the case of upwards switching.
Only the ten current curves 41 in the case of even switching processes are illustrated in Fig. 4 such that the ten current curves 42 in the case of odd switching processes (see Fig. 1) are not illustrated since they have been filtered = CA 02947094 2016-10-26 27003W0 HJB/sr 11 out.
The 20 current curves 41, 42 from Fig. 1 are illustrated in Fig. 5 chronologically side by side. In this connection, a time point (e.g. t3 or t6), at which a current curve 41, 42 ends, corresponds to a time point at which a current curve illustrated adjacent thereto begins. In other words, the current curves illustrated in Fig. 5 are not illustrated in a temporally-superimposed manner.
A transformer 6 with a tap changer 20 and a device 30 according to the invention for testing the tap changer 20 are illustrated in Fig. 6.
The transformer 6 comprises a winding 10 which has a plurality of taps or tappings 12, 13. The tap changer 20 comprises two tap selectors 14, 15. In this regard, the one tap selector 14 is connected to one of the right-hand or even taps 12 and the other tap selector 15 is connected to one of the left-hand or odd taps 13. Furthermore, the tap changer 20 comprises a first connection 21 and a first resistor 22 which are assigned to the tap selector 15 as well as a second connection 24 and a second resistor 23 which are assigned to the tap selector 14. In the case of the condition illustrated in Fig. 6, a current I
flows at connection 11 into the winding 10 and flows out from the winding 10 at the tap 13 which is in contact with the tap selector 15.
In order to now change the transmission ratio of the transformer 6, a switch of the tap changer 20 is switched from connection 21 to connection 24. The switch 25 here contacts in a first step both the first connection 21 and the first resistor 22 such that the current I flows through the first resistor 22 if the switch 25 loses the contact to the first connection 21 in the second step. In the third step, the switch 25 contacts both the first resistor 22 and the second resistor 23 such that the current I flows both via the first resistor 22 and via the second resistor 23 and thus both via the tap selector 15 and the corresponding tap 13 and via the tap selector 14 and the corresponding taps 12. If the switch 25 is switched further, the switch 25 loses the contact with the first resistor 22 in the fourth step such that the current I flows in the fourth step only via the second resistor 23 and the tap selector 14 and the corresponding tap 12. If the switch 27003W0 HJB/sr 12 25 is switched further, the switch 25 contacts the second connection 24 in the fifth step such that the second resistor 23 is virtually short-circuited. The current I flows via the second connection 24 as well as the tap selector 14 and the associated tap 12 such that the transmission ratio of the transformer 6 changes correspondingly. If the switch 25 is switched further, the switch 25 loses the contact to the second resistor 23 in the sixth and final step, whereby the switching process or the actuation of the tap changer 20 for changing the transmission ratio of the transformer 6 has finally ended.
As soon as the tap selector 15 is switched in a currentless manner (i.e. with the fourth step), the tap selector can be connected to another left-hand or odd tap 13. In order to once again change the transmission ratio of the transformer 6, the switch 25 is switched in a similar manner as previously described from the second connection 24 to the first connection 21.
In order to test the tap changer 20, the device 30 according to the invention is present which has a current source 31 and an ammeter 32. The current I is generated by means of the current source 31 which flows through the winding 10 and the tap changer 20 arranged in series with the winding 10. A time curve of the current I flowing through the winding 10 and the tap changer 20 is in particular determined during the switching over of the tap changer 20 with the corresponding measuring device 9 (see Fig. 8) of the device 30 according to the invention.
If the measuring device 9 (see Fig. 8) is also designed to determine a time curve of the voltage falling via the winding 10, the time curve of the electrical resistance value of the winding 10 can be determined by the controller 7 (see Fig. 8) of the device 30 by dividing, for each point in time, the voltage determined at this point in time by the current determined at this point in time.
.. The device 30 according to the invention is then capable of illustrating, in a temporally-superimposed manner, time curves of the resistance values which have been determined and identified during the switching processes of the tap changer 20.
= CA 02947094 2016-10-26 27003W0 HJB/sr 13 A multi-phase transformer 5 is illustrated in Fig. 7 which has three phases with respectively one winding 1-3 in a Y-interconnection. In this regard, each phase or winding 1-3 has a tap changer 20 (not illustrated in Fig. 7) in order to change the transmission ratio of the transformer 5 in the same manner as was previously described with regard to Fig. 6.
In order to test the tap changer, the device 30 according to the invention generates a first direct current Ii which is supplied to the end of the first winding 1 facing away from the star point 4 and a second direct current 12 which is, on the one hand, taken away from the end of the third winding 3 facing away from the star point 4 and, on the other hand, is supplied to the end of the second winding 2 facing away from the star point 4. It can be discerned that the first direct current 11 also flows away from the star point 4 to the device 30. In other words, the test signals or direct currents 11, 12, which are supplied to each winding 1-3, comprise the same value.
The time curves of the resistance values of the three windings 1-3 are determined, while the tap changers are repeatedly switched in order to change the transmission ratio of the multi-phase transformer 5. A plurality of determined or identified resistance value curves are illustrated in a temporally-superimposed manner for each tap changer in order to test the correct operation of the tap changers.
A further embodiment of the device 30 according to the invention is schematically illustrated in Fig. 8. In addition to a current source 31 which corresponds to the test signal generation means, the device 30 comprises a controller 7, a display 8 and a measuring means 9 by means of which a time curve of the electrical resistance value can be determined or identified. The determined or identified time curves of the resistance value are illustrated on the display 8 in a temporally-superimposed manner.
=
27003W0 HJB/sr 14 LIST OF REFERENCE NUMERALS
1-3 Winding 4 Star point 5 Three-phase alternating current transformer 6 Transformer 7 Controller 8 Display 9 Measuring device 10 Winding 14,15 Tap selectors 12, 13 Taps Tap changer 15 11, 21, 24 Connection 22, 23 Resistor Device 31 Current source 32 Ammeter 20 41 Current curve in the case of downwards switching 42 Current curve in the case of upwards switching 1,11,12 Direct current Time tx Time point
Claims (12)
1. A method for testing a tap changer of a transformer, wherein the tap changer is designed to change a transmission ratio of the transformer, wherein the method comprises the following steps:
generating a test signal which is supplied to a winding of the transformer and to the tap changer, actuating the tap changer in order to change the transmission ratio, and determining an electrical resistance value of the winding of the transformer during the step of actuating the tap changer depending on the test signal.
generating a test signal which is supplied to a winding of the transformer and to the tap changer, actuating the tap changer in order to change the transmission ratio, and determining an electrical resistance value of the winding of the transformer during the step of actuating the tap changer depending on the test signal.
2. The method according to claim 1, wherein:
the transformer is a multi-phase transformer, a separate tap changer is present for each phase of the transformer which is designed to change a transmission ratio of the transformer, respectively one test signal is generated simultaneously for each phase of the transformer which is supplied to a winding of the transformer assigned to the respective phase and to the tap changer assigned to the winding, the tap changers are actuated in order to change the transmission ratio, and respectively one electrical resistance value is determined for each winding during the step of actuating the tap changers.
the transformer is a multi-phase transformer, a separate tap changer is present for each phase of the transformer which is designed to change a transmission ratio of the transformer, respectively one test signal is generated simultaneously for each phase of the transformer which is supplied to a winding of the transformer assigned to the respective phase and to the tap changer assigned to the winding, the tap changers are actuated in order to change the transmission ratio, and respectively one electrical resistance value is determined for each winding during the step of actuating the tap changers.
3. The method according to claim 2, wherein the test signals for each phase are generated identically in terms of value.
4. The method according to any one of claims 1-3, wherein the test signal is a direct current signal.
5. The method according to any one of claims 1-4, wherein the determination of the respective electrical resistance value comprises a measurement of a current (1; h; 12) through the respective winding and a measurement of a voltage which falls at the respective winding as well as a determination of the electrical resistance value by means of a quotient from the voltage and the current (1; 11; 12).
6. The method according to any one of claims 1-5, wherein the electrical resistance value is a direct current resistance value or an alternating current resistance value.
7. The method according to any one of claims 1-6, wherein the method comprises outputting the respective electrical resistance value.
8. The method according to claim 7 wherein:
the determination of the respective electrical resistance value comprises a determination of a curve of the respective electrical resistance value over time (t), and the output of the respective electrical resistance value comprises an illustration of the curve of the respective electrical resistance value over time (t).
the determination of the respective electrical resistance value comprises a determination of a curve of the respective electrical resistance value over time (t), and the output of the respective electrical resistance value comprises an illustration of the curve of the respective electrical resistance value over time (t).
9. A device for testing a tap changer of a transformer, wherein the tap changer is designed to change a transmission ratio of the transformer, wherein the device comprises test signal generation means, measuring means and control means, wherein the device is designed to supply a test signal to a winding of the transformer and to the tap changer by means of the test signal generation means and wherein the device is designed to determine an electrical resistance value of the winding of the transformer by means of the measuring means and the control means during an actuation of the tap changer depending on the test signal.
10. The device according to claim 9 wherein:
the transformer is a multi-phase transformer, a separate tap changer is present for each phase of the transformer which is designed to change a transmission ratio of the transformer, the device is designed to simultaneously generate respectively one test signal for each phase of the transformer by means of the test signal generation means and to supply said test signal to a winding of the transformer assigned to the respective phase and to the tap changer assigned to the winding and the device is designed to determine by means of the measuring means and the control means respectively one electrical resistance value for each winding during the actuation of the tap changer depending on the test signal.
the transformer is a multi-phase transformer, a separate tap changer is present for each phase of the transformer which is designed to change a transmission ratio of the transformer, the device is designed to simultaneously generate respectively one test signal for each phase of the transformer by means of the test signal generation means and to supply said test signal to a winding of the transformer assigned to the respective phase and to the tap changer assigned to the winding and the device is designed to determine by means of the measuring means and the control means respectively one electrical resistance value for each winding during the actuation of the tap changer depending on the test signal.
11. The device according to claim 9 or 10, wherein:
the device comprises a display, and the device is designed such that the control means illustrate each resistance value on the display.
the device comprises a display, and the device is designed such that the control means illustrate each resistance value on the display.
12. The device according to any one of claims 9-11 wherein the device is designed to perform the method according to any one of claims 1-8.
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|---|---|---|---|
| ATA50460/2014 | 2014-07-02 | ||
| ATA50460/2014A AT516004B1 (en) | 2014-07-02 | 2014-07-02 | Method and device for testing a tap changer of a transformer |
| PCT/EP2015/064713 WO2016001150A1 (en) | 2014-07-02 | 2015-06-29 | Method and device for testing a tap changer of a transformer |
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| CA2947094C true CA2947094C (en) | 2018-10-16 |
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| KR102235052B1 (en) * | 2019-09-26 | 2021-04-01 | 한국전력공사 | Apparatus and method for analyzing oltc performance |
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| GB2158253B (en) * | 1984-04-26 | 1987-06-17 | Ferranti Plc | Transformer tap changing switch wear monitor |
| RU2290653C2 (en) * | 2004-12-20 | 2006-12-27 | Юрий Алексеевич Федоров | Mode of evaluation of parameters of the process of switching of fast-acting regulator of contactor's contacts under loading in a three-phase transformer without its opening and an arrangement for its fulfillment |
| RU2342673C2 (en) * | 2006-10-02 | 2008-12-27 | Георгий Михайлович Михеев | Method and device for time chart construction for selector and contactor of high-speed regulator-under-load (rul) |
| CN101458308B (en) * | 2009-01-14 | 2011-05-11 | 吉林省电力有限公司电力科学研究院 | AC test device for transformer on-load tap-changer operating characteristic |
| DE102009014333A1 (en) * | 2009-03-21 | 2010-09-30 | A. Eberle Gmbh & Co. Kg | Device for monitoring tap changers |
| EP2244272B1 (en) * | 2009-04-20 | 2012-06-06 | ABB Technology Ltd | Measuring contact sequence in a tap changer |
| WO2011085763A1 (en) * | 2010-01-16 | 2011-07-21 | Maschinenfabrik Reinhausen Gmbh | Method for measuring the switching time of an on-load tap changer and circuit for measuring switching time |
| KR101037323B1 (en) * | 2010-12-30 | 2011-05-26 | (주)엘레시스 | Apparatus and method for evaluating health of tab changer |
| CN104246948B (en) * | 2012-04-16 | 2017-03-15 | 赖茵豪森机械制造公司 | Method for monitoring diversity switch |
| CN102981055A (en) * | 2012-11-30 | 2013-03-20 | 江苏省电力公司涟水县供电公司 | Tester for direct current resistance of transformer and parameter of on-load tap-changer of transformer |
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| CN106415290A (en) | 2017-02-15 |
| CN106415290B (en) | 2020-03-03 |
| KR20160147966A (en) | 2016-12-23 |
| MX2016015596A (en) | 2017-02-27 |
| CA2947094A1 (en) | 2016-01-07 |
| AT516004B1 (en) | 2017-04-15 |
| ZA201608245B (en) | 2017-09-27 |
| MX357248B (en) | 2018-07-02 |
| AT516004A1 (en) | 2016-01-15 |
| BR112016026187A2 (en) | 2017-08-15 |
| BR112016026187B1 (en) | 2022-09-27 |
| EP3164725B1 (en) | 2021-04-21 |
| AU2015282647B2 (en) | 2018-08-09 |
| PL3164725T3 (en) | 2021-10-04 |
| EP3164725A1 (en) | 2017-05-10 |
| ES2874876T3 (en) | 2021-11-05 |
| RU2657326C1 (en) | 2018-06-13 |
| AU2015282647A1 (en) | 2016-11-17 |
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