CN102095992A - Method for analyzing wiring of differential protection CT (Computed Tomography) loop based on exciting transformer - Google Patents
Method for analyzing wiring of differential protection CT (Computed Tomography) loop based on exciting transformer Download PDFInfo
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- CN102095992A CN102095992A CN2009103115951A CN200910311595A CN102095992A CN 102095992 A CN102095992 A CN 102095992A CN 2009103115951 A CN2009103115951 A CN 2009103115951A CN 200910311595 A CN200910311595 A CN 200910311595A CN 102095992 A CN102095992 A CN 102095992A
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Abstract
The invention relates to a method for analyzing the wiring of a differential protection CT (Computed Tomography) loop based on an exciting transformer, which comprises the following steps: 1) drafting a correct vector diagram of the loop; 2) drafting an actually measured vector diagram based on a reference voltage; 3) outputting a wiring correctness analysis result of the loop; 4) finishing the measurement and judgment of the wiring correctness of all combined phase units; 5) obtaining the parameters which are needed by each side CT combined phase of the differential protection of the exciting transformer; 6) drafting a vector diagram of options selected by each side CT of the differential protection loop of the exciting transformer by adopting a simultaneous same-phase measurement method of each side based on the reference voltage; and 7) converting the measured value of the differential protection CT loop of the exciting transformer according to the exciting transformer and parameters thereof, analyzing and judging the analysis result of the combined phase, and outputting the analysis result. The method provided by the invention has the advantage of reliable analysis result, and the accuracy is greatly enhanced.
Description
Technical field
The present invention relates to relay protection CT circuit connection correctness analytical approach in a kind of electric system, relate in particular to a kind of wiring to exciting transformer differential protecting CT loop in the electric system whether correct, close the analytical approach of whether correctly analyzing, judge and provide the false wiring type mutually.
Background technology
Will satisfy to differ 120 ° between phase and phase for the correctness of single CT circuit connection, and phase sequence is identical, is positive sequence or negative phase-sequence, each phase current two sub-value is identical.It is identical with the primary current value in measurement loop that the current effective value of measuring according to secondary multiply by the primary current value that the CT transformation-ratio meter calculates.
For the exciting transformer differential protection, calculate the resultant vector of each phase of mains side and the resultant vector of each phase of load side.When each winding all satisfies the phase angle balance, promptly differ 120 ° between phase and phase, and phase sequence is identical, be positive sequence or negative phase-sequence.Simultaneously mains side and load side every mutually vector and when being zero, promptly amplitude equates, to differ 180 ° be that decidable exciting transformer differential protecting CT circuit connection is correct to angle.
The correctness of exciting transformer differential protecting CT circuit connection directly influences the normal operation of electric power system.The correctness of relay protection CT circuit connection is in time made analysis, judged; requisite important step during to be that transformer station is newly-built put into operation, overhaul; exciting transformer differential protecting CT circuit connection correctness is analyzed at present; main by manually carrying out Zhao especially main transformer, bus differential protecting CT loop; the staff will pass through a large amount of calculating; manual drawing current vector figure, and then draw the analysis result of relay protection CT circuit connection correctness according to result of calculation and vector plot.The The whole analytical process calculated amount is big, and needs the staff rule of thumb to judge, so there is the shortcoming that efficient is low, error is big.The flow process that the tradition manual method is analyzed relay protection CT circuit connection correctness is as follows: obtain data: the current amplitude, phase data and the correlation parameter that obtain each each phase of winding of exciting transformer differential protecting CT loop.Generally obtain (as using two pincers volt-ampere phase meters), the measured value of current amplitude, phase data and the measurement loop measured is compared, judge the correctness of single CT circuit connection by power measuring instrument.For two circle main transformers, use two pincers volt-ampere phase meters measure successively each phase (A, B, C, N) current amplitude of high-pressure side CT and low-pressure side CT and phase place and with compared by situation to determine the correctness of each side CT circuit connection according to meritorious, idle the sending of measuring the loop.Calculate electric current: calculate the coefficient of balance of each side earlier according to rated voltage and CT no-load voltage ratio, and then current amplitude is converted according to coefficient of balance.Adjust phase place: current phase is adjusted according to the mode of connection.Draw vector plot: according to parameter manual drawing vector plots such as reference voltage, current amplitude, phase angles.Analysis and judgement: judge CT circuit connection correctness according to each side through current value after the EQUILIBRIUM CALCULATION FOR PROCESS and vector plot, if wiring error needs profiling error reason and correcting method.Judge according to the pacing items that mains side resultant vector and load side resultant vector should equal and opposite in directions, direction is opposite whether whole differential circuit wiring is correct.If incorrect, then rule of thumb judge by the staff, provide correction scheme, this step does not have the flow process of standard, fully by staff quality's decision, if there is not experience, judging so wastes time and energy, and is difficult to judge for complicated error situation.
Summary of the invention
For solve under the at present artificial situation exciting transformer differential protecting CT circuit connection error situation judged waste time and energy, to the demanding situation of staff, the invention provides a kind of reliability height, safe in utilization simple, easy to operate based on exciting transformer differential protecting CT circuit connection analysis and judgement method.
The technical solution that the present invention solves the problems of the technologies described above is:
A kind of method of analyzing based on exciting transformer differential protecting CT circuit connection, its special character is: this method may further comprise the steps:
1) obtain exciting transformer differential protection route survey value and parameter, bus differential protecting route survey value and parameter:
2) according to the exciting transformer parameter exciting transformer differential protection route survey value is converted or according to the bus parameter bus differential protecting route survey value is converted, its specific implementation is:
2.1) with this winding of N phase current correction of winding or circuit or A, B, the C phase current of circuit;
2.2) coefficient of balance of each winding of calculating transformer or each circuit of bus;
2.3) according to the convert current effective value of this winding or this circuit of the coefficient of balance of each winding of transformer or each circuit of bus;
2.4) all current phases are deducted the reference phase power angle that the user imports;
2.5) judge whether reference voltage is Ua, if then direct execution in step 2.6); If not then reference voltage being converted to behind the Ua execution in step 2.6 again);
2.6) judge it is that exciting transformer differential protection circuit is analyzed or the bus differential protecting circuit is analyzed, if select exciting transformer differential protection circuit is analyzed, then the mode of connection of unified transformer is preserved parameter and execution in step 3 after converting then); If select the bus differential protecting circuit is analyzed, then directly preserve the parameter after converting and change step 3) over to;
3) do you judge according to each winding measured value of exciting transformer differential protection or each route survey value of bus differential protecting of having converted whether wiring correct? if correctly execution in step 6); If incorrect then execution in step 4);
4) carry out the first time and revise, and judge: correction for the first time comprises with reference to winding or circuit correction, each winding or the balance correction of circuit phase angle and the correction of phase angle positive sequence; Do you after correction finishes for the first time, judge whether the mode of connection correct? if then carry out step 6); If not, then carry out step 5);
5) generate revised current effective value, and preserve the modified value when satisfying correctness condition;
6) output analysis result.
Above-mentioned steps 4) specific implementation with reference to the winding correction in is: directly A phase phase place is made as 0 °, B and is made as 120 °, C mutually and is made as 240 ° mutually, or uses corresponding method to revise according to its three-phase current phase place misjudgment; In when carrying out the correction of phase angle balance for a certain winding or circuit, judge whether that at first a certain and other two alternate phase places all are 60 °? if, then revise, if not, then do not revise; The specific implementation of its correction is: find out the middle phase in the three-phase current, promptly with other 2 angles be 60 ° mutually, add 180 ° for then middle phase phase angle; Do you when a certain winding or circuit carry out the correction of phase angle positive sequence, judge at first that B phase phase place equals A phase phase place in the three-phase phase and add 120 °? if then do not need to revise; If not, then to revise, the specific implementation of its correction is: the phase place of exchange A, B two-phase can be finished correction.
Above-mentioned steps 5) in, when revising in anglec of rotation mode, its specific implementation correction and deterministic process are: with 60 ° is circulation rotation in one-period at interval, winding of each rotation, once rotate 60 °, carry out a correctness after each rotation and judge that if satisfy correct condition, then execution in step 6); If do not satisfy then carry out step 5) and continue rotation, till satisfying correctness condition; Still can not satisfy correctness condition if all windings all rotate to finish successively, can't judge promptly whether wiring correctly then carries out step 7).
Advantage of the present invention is as follows:
1) analysis result is reliable, and accuracy significantly improves.
The analytical approach in relay protection of power system CT provided by the present invention loop is carried out twice analysis; judge at each CT loop and the differential CT of exciting transformer loop; can provide perfect wiring error situation and correction scheme in the final analysis result that forms; need not again the people for judging; its analysis result reliability obviously analytical approach than traditional is strong; and not influenced by aspects such as subjective quality of staff and objective environment factor, make precision of analysis significantly improve.
2) simple to operate, safe and reliable.
The present invention oversimplifies the analytical work of electric relay protection CT circuit connection, only need simply measure and can analyze and provide the result automatically, and staff's technical merit is required significantly to reduce.
3) input of 4 road electric currents is arranged, can carry out the measurement of 4 road current amplitudes, phase place simultaneously at most, measure when satisfying 4 current return amplitudes of transformer and phase place at most, guaranteed to close the accuracy of phase time data, avoided owing to load in the measuring process changes, passes through the mistake of closing the phase result that power flow direction changes and causes.
Description of drawings
Schematic flow sheet for connection analysis method provided by the present invention;
Fig. 1 is for the present invention is meritorious, the idle synoptic diagram that concerns that is subjected to situation and quadrant that send.
Embodiment
The idiographic flow that the invention provides a kind of exciting transformer differential protecting CT circuit connection correctness analytical approach wiring analysis is as follows:
1, obtain the basis for estimation of judging protection CT circuit connection correctness:
Meritorious, idle send, be subjected to situation by what the transformer station of measuring loop, stoichiometric point or interrelate with it obtained this loop, meritorious, idle sending according to this loop are subjected to the correct phase angle of definite this unit secondary such as situation, primary current effective value and the effective value of electric current, need select a reference voltage when measuring, the current phase of being surveyed is meant the phase place of tested electric current with respect to this reference voltage.Reference voltage can be selected by the operator when measuring voluntarily.
2, according to the basis for estimation the obtained correct vector plot that draws:
For example: pass through measurement loop, stoichiometric point or the transformer station that interrelates with it obtain the meritorious of this loop, idle send that to be subjected to situation be that (sending and being subjected to situation is benchmark with the bus, flow into bus for being subjected to, flow out bus for sending, send on the occasion of, be subjected to be negative value): send meritorious 25MW, send idle 25MW, can calculate tg φ=Q/P=1 so, pass through arctg=1 so, just can obtain φ=45 ° and in first quartile, if be reference voltage with Ua this moment, the phasing degree of Ia is 45 ° so, come the picture vector plot according to positive sequence, the phasing degree of Ib is 165 °, and the phasing degree of Ic is 285 °.If it is meritorious, idle send that to be subjected to situation be to send meritorious 25MW, be subjected to idle-25MW, can calculate tg φ=Q/P=-1 so, pass through arctg-1 so, just can obtain φ=135 ° or 315 °, according to meritorious, the idle situation that is subjected to of sending, the phasing degree should be at the 4th quadrant as can be seen, the phasing degree just should be 315 ° so, and is meritorious, the idle relation that is subjected to situation and quadrant of sending is referring to Fig. 1, so if be reference voltage with Ua this moment, the phasing degree of Ia is 315 ° so, come the picture vector plot according to positive sequence, the phasing degree of Ib is 75 °, and the phasing degree of Ic is 195 °.The calculating of protection CT secondary current effective value is relevant with the no-load voltage ratio in metering CT loop; if the no-load voltage ratio of two CT groups is identical, the effective value of secondary current just equate or the primary current that will measure the CT loop secondary current effective value after according to the no-load voltage ratio conversion equal.If the no-load voltage ratio difference of two CT groups, the effective value of secondary current is just unequal, and the primary current that need record measurement loop calculates the secondary current effective value in protection loop according to the no-load voltage ratio of protection loop CT.After phase angle and amplitude were determined, correct vector plot just can have been drawn out.
3, the phase place and the amplitude of each phase current of actual measurement protection CT loop:
With Ua is the phasing degree that reference voltage records Ia, Ib, Ic.With the phase voltage table record secondary current effective value (this measured value will with measure primary current that the CT loop records no-load voltage ratio according to protection loop CT, the secondary current effective value that calculates the protection loop equates).Draw out actual vector plot on this basis.
4, with the vector plot in the protection CT loop of actual measurement with according to measure correct vector plot that the CT loop drawn compare analysis, judge the correctness of this protection loop CT wiring:
5, according to exciting transformer and parameter thereof exciting transformer differential protecting CT loop measured value is converted;
6, by above-mentioned work each side winding connection error analysis of exciting transformer, judgement are finished, the staff need correct the wiring of mistake, again measure after the correction, till wiring is correct, to notice in the wiring correction process that each side CT loop extension line of conventional main transformer is an end of the same name, guarantee it is that end of the same name is drawn.Adopt the simultaneously-measured method of each side homophase, the correctness of analyze, each side of judgement exciting transformer differential protection being closed the phase result: the phase parameters needed was closed in needed exciting transformer differential protecting CT loop in the middle of input was analyzed before analyzing.
Close phase for exciting transformer differential protecting CT loop: comprise winding connection mode of exciting transformer, each winding CT no-load voltage ratio, each winding rated voltage, main electrical scheme situation and the pairing switch number of each CT winding (being used to draw vector plot); Whether the difference of a winding connection mode of each side of exciting transformer and cause the compensation of each side primary current phase difference corrects compensation by each side CT mode of connection; Import selected reference voltage.
Last analysis result has two kinds of situations: the one, and wiring is correct, and the 2nd, wiring error.
7. the algorithm basic theories is verified and conclusion
For the judgement of each side CT circuit connection correctness of exciting transformer be based on each loop meritorious, idle send the actual conditions that are subjected to, so if determined that each loop is meritorious, idle sending be subjected to situation just can be easily, the correctness of definite CT circuit connection intuitively.After having guaranteed each side CT circuit connection correctness of exciting transformer; adopt the simultaneously-measured method of each side homophase to do the phase of closing in exciting transformer differential protecting CT loop; maximum like this each side of exciting transformer that guaranteed is measured the simultaneity of numerical value, has guaranteed that each side of exciting transformer closes facies analysis result's accuracy.
The conclusion of deriving according to algorithm of deriving with practical conditions is consistent fully with the factual error situation.
Claims (3)
1. method of analyzing based on exciting transformer differential protecting CT circuit connection is characterized in that: may further comprise the steps:
1) obtain exciting transformer differential protection route survey value and parameter, bus differential protecting route survey value and parameter:
2) according to the exciting transformer parameter exciting transformer differential protection route survey value is converted or according to the bus parameter bus differential protecting route survey value is converted, its specific implementation is:
2.1) with this winding of N phase current correction of winding or circuit or A, B, the C phase current of circuit;
2.2) coefficient of balance of each winding of calculating transformer or each circuit of bus;
2.3) according to the convert current effective value of this winding or this circuit of the coefficient of balance of each winding of transformer or each circuit of bus;
2.4) all current phases are deducted the reference phase power angle that the user imports;
2.5) judge whether reference voltage is Ua, if then direct execution in step 2.6); If not then reference voltage being converted to behind the Ua execution in step 2.6 again);
2.6) judge it is that exciting transformer differential protection circuit is analyzed or the bus differential protecting circuit is analyzed, if select exciting transformer differential protection circuit is analyzed, then the mode of connection of unified transformer is preserved parameter and execution in step 3 after converting then); If select the bus differential protecting circuit is analyzed, then directly preserve the parameter after converting and change step 3) over to;
3) do you judge according to each winding measured value of exciting transformer differential protection or each route survey value of bus differential protecting of having converted whether wiring correct? if correctly execution in step 6); If incorrect then execution in step 4);
4) carry out the first time and revise, and judge: correction for the first time comprises with reference to winding or circuit correction, each winding or the balance correction of circuit phase angle and the correction of phase angle positive sequence; Do you after correction finishes for the first time, judge whether the mode of connection correct? if then carry out step 6); If not, then carry out step 5);
5) generate revised current effective value, and preserve the modified value when satisfying correctness condition;
6) output analysis result.
2. a kind of method of analyzing based on exciting transformer differential protecting CT circuit connection according to claim 1, it is characterized in that: the specific implementation with reference to the winding correction in the described step 4) is: directly A phase phase place is made as 0 °, B and is made as 120 °, C mutually and is made as 240 ° mutually, or uses corresponding method to revise according to its three-phase current phase place misjudgment; In when carrying out the correction of phase angle balance for a certain winding or circuit, judge whether that at first a certain and other two alternate phase places all are 60 °? if, then revise, if not, then do not revise; The specific implementation of its correction is: find out the middle phase in the three-phase current, promptly with other 2 angles be 60 ° mutually, add 180 ° for then middle phase phase angle; Do you when a certain winding or circuit carry out the correction of phase angle positive sequence, judge at first that B phase phase place equals A phase phase place in the three-phase phase and add 120 °? if then do not need to revise; If not, then to revise, the specific implementation of its correction is: the phase place of exchange A, B two-phase can be finished correction.
3. a kind of method of analyzing based on exciting transformer differential protecting CT circuit connection according to claim 2, it is characterized in that: in the step 5), when revising in anglec of rotation mode, its specific implementation correction and deterministic process are: with 60 ° is circulation rotation in one-period at interval, winding of each rotation once rotates 60 °, carries out a correctness after each rotation and judges, if satisfy correct condition, then execution in step 6); If do not satisfy then carry out step 5) and continue rotation, till satisfying correctness condition; Still can not satisfy correctness condition if all windings all rotate to finish successively, can't judge promptly whether wiring correctly then carries out step 7).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009103115951A CN102095992A (en) | 2009-12-15 | 2009-12-15 | Method for analyzing wiring of differential protection CT (Computed Tomography) loop based on exciting transformer |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009103115951A CN102095992A (en) | 2009-12-15 | 2009-12-15 | Method for analyzing wiring of differential protection CT (Computed Tomography) loop based on exciting transformer |
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| CN102095992A true CN102095992A (en) | 2011-06-15 |
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| CN2009103115951A Withdrawn CN102095992A (en) | 2009-12-15 | 2009-12-15 | Method for analyzing wiring of differential protection CT (Computed Tomography) loop based on exciting transformer |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114509616A (en) * | 2021-08-26 | 2022-05-17 | 国网河北省电力有限公司石家庄供电分公司 | Method for troubleshooting power failure analysis to-home problems |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114509616A (en) * | 2021-08-26 | 2022-05-17 | 国网河北省电力有限公司石家庄供电分公司 | Method for troubleshooting power failure analysis to-home problems |
| CN114509616B (en) * | 2021-08-26 | 2023-07-14 | 国网河北省电力有限公司石家庄供电分公司 | Power failure analysis household problem investigation method |
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Open date: 20110615 |