CN101788629A - Connection analysis method for conventional transformer relaying CT circuit in electric system - Google Patents
Connection analysis method for conventional transformer relaying CT circuit in electric system Download PDFInfo
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Abstract
The invention relates to a connection analysis method for a conventional transformer relaying CT circuit in an electric system. The method comprises the following steps of: (1) acquiring the parameters of each winding in a conventional transformer differential protection circuit; (2) measuring the phase position and the amplitude value of the current of each phase of each winding in the conventional transformer differential protection circuit; (3) calculating and obtaining the correct current phase of the secondary circuit of each winding in the conventional transformer differential protection circuit based on the acquired parameters; (4) comparing, judging the connection correctness of the conventional transformer differential protection circuit to be measured, and generating the corresponding connection status code; (5) outputting the results; and (6) carrying out the primary-side and secondary-side synthesis and outputting the synthesis results. The invention solves the problem that the connection error condition judgment of the relaying CT circuit in the electric system costs too much time and energy and has high requirement on the working people under the existing manual condition, and provides a method for analyzing and judging the connection correctness of the relaying CT circuit in the electric system, which has the advantages of high reliability, safe and simple use and convenient operation.
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 conventional 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 conventional 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 conventional transformer differential protecting CT circuit connection is correct to angle.
Comprehensive above-mentioned condition is summarized the correct condition of the differential CT circuit connection of conventional transformer:
1) all windings satisfy the phase angle balance, promptly differ 120 ° between phase and phase;
2) all winding phase sequences are identical and all be positive sequence, promptly are shown as A, B, C in vector plot clockwise successively;
3) the polarity lead-out mode of each side CT is identical;
4) amplitude of each phase secondary current equates;
5) vector of mains side resultant vector and load side resultant vector and be zero (be amplitude equates, phase angle differ 180 °).
When wiring error, correct vector and actual measurement vectorial inequality compared with the correct vector plot that the measurement loop analysis draws according to the phasor graph of actual measurement and can be judged the place of wiring error.
Three kinds of basic conditions are generally arranged under the situation of wiring error, and one for the polarity of certain phase connects instead, is connected into negative drawing as just drawing, and will cause 180 ° of the phase phasic differences of electric current like this; Two is wrong between certain two-phase, and to the B phase, the misconnection of B phase will cause the phase sequence mistake of electric current like this to the A phase as the misconnection of A phase; Three be the CT no-load voltage ratio of certain phase, certain two-phase or three-phase with wrong, thereby cause the vector of mains side and load side and non-vanishing, the spill current increase can cause differential protection malfunction.
The correctness of relay protection of power system 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; relay protection of power system CT circuit connection correctness is analyzed at present; main by manually carrying out---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:
1) obtains data: the current amplitude, phase data and the correlation parameter that obtain each each phase of winding of conventional 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.
2) 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.
3) adjust phase place: current phase is adjusted according to the mode of connection.
4) draw vector plot: according to parameter manual drawing vector plots such as reference voltage, current amplitude, phase angles.
5) 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.
The manual method of traditional relay protection circuit wiring analysis exists following shortcoming or deficiency:
1, analysis result reliability and poor accuracy.Owing to there is not unified working specification, there is certain randomness in operation; In addition, the height of staff's professional skill, objective environment factor etc. all can impact analysis, the accuracy of judgement.
2, the professional ability to operating personnel requires high.Operating personnel should be familiar with the electric system knowwhy, and will possess rich practice experience, and whether can judge relay protection CT circuit connection correct, analyze then and where make mistakes, how to revise.
3, work complexity height, inefficiency.Especially the data computation amount is big in the main transformer differential CT loop analysis deterministic process, and the manually-operated inefficiency is wasted time and energy, and in complicated operations flow process and lot of data computation process, makes a mistake unavoidably.
Summary of the invention
For solve under the at present artificial situation relay protection of power system CT circuit connection error situation judged waste time and energy, to the demanding situation of staff, the invention provides the analysis and judgement method of a kind of reliability height, simple, easy to operate relay protection of power system CT circuit connection correctness safe in utilization.
The technical solution that the present invention is directed to above-mentioned technical matters is:
A kind of connection analysis method for conventional transformer relaying CT circuit in electric system, its special character is: this method may further comprise the steps:
1) obtain the parameter of each winding of conventional transformer differential protection circuit: described parameter comprises meritorious value, idle value and reference voltage; Described reference voltage is a certain phase voltage or the line voltage of measured winding;
2) measure the phase place and the amplitude of each each phase current of winding of conventional transformer differential protection circuit: measure each winding Ia, Ib, Ic phase place respectively with respect to reference voltage;
3) according to the calculation of parameter obtained and draw the correct current phase of each winding secondary circuit of conventional transformer differential protection circuit: calculate current phase with reference to mutually according to meritorious value and idle value, according to three-phase current phase place 120 ° and the equal-sized pacing items of amplitude each other, draw the current phase of other two-phases;
4) with step 2) in the correct current phase that calculates in the phase place of each each phase current of winding of conventional transformer differential protection circuit of recording and the step 3) compare, judge the correctness of tested conventional transformer differential protection circuit wiring, generate corresponding wiring state sign indicating number, the wiring state sign indicating number comprises correct wiring sign indicating number and false wiring sign indicating number, the corresponding a kind of wiring situation of each wiring state sign indicating number;
5) output result: described output result comprises the correct and wiring error of wiring; If the wiring state sign indicating number of each winding is correct wiring sign indicating number, then output connection is correct; If the wiring state sign indicating number of arbitrary winding is the false wiring sign indicating number, then output connection mistake and each winding connection situation;
6) carry out the synthetic and synthetic result of output in former and deputy limit
6.1) obtain conventional transformer differential protection route survey value and parameter:
Conventional transformer differential protection route survey value comprises: the effective value of each winding current and phase place, the current effective value of described arbitrary winding are the current effective values of this winding A, B, C, N phase; The current phase of described each winding is the phase place with respect to reference voltage; Described reference voltage is the line voltage or the phase voltage of arbitrary winding;
The parameter of conventional transformer differential protection circuit comprises: the mode of connection of conventional transformer, each winding CT no-load voltage ratio, each winding rated voltage, each winding power supply mode, number of switches, whether through secondary connection adjustment and each winding numbering, with reference to the phase power angle;
6.2) according to the conventional transformer parameter conventional transformer differential protection route survey value is converted, its specific implementation is:
6.2.1) calculate the coefficient of balance of each winding of conventional transformer;
6.2.2) according to the convert current effective value of this winding of the coefficient of balance of each winding of conventional transformer;
6.2.3) all current phases are deducted with reference to the phase power angle;
6.2.4) judge whether reference voltage is Ua, if then direct execution in step 6.2.5); If not then reference voltage being converted to behind the Ua execution in step 6.2.5 again);
6.2.5) mode of connection of unified conventional transformer, preserve parameter and execution in step 6.3 after converting then)
6.3) according to the wiring state sign indicating number that draws in the step 4) current measured value is revised
For a certain winding, carry out reverse correction according to its wiring state sign indicating number;
6.4) close mutually and export the angular difference and the difference in magnitude of former limit and secondary synthetic quantity
It is synthetic respectively mains side and load side to be carried out vector, draws former limit A, B, C three-phase and secondary A, B, C three-phase electricity flow valuve, and the angular difference of more former respectively limit and secondary three-phase electricity flow valuve and difference in magnitude are also exported.
The above step 6.2.1) computing method for the coefficient of balance of conventional transformer differential protection in are:
6.2.1.1) according to formula
Calculate the secondary rated current of each winding;
6.2.1.2) one coefficient of balance establishing each winding secondary rated current maximum is 1, calculates the coefficient of balance of other windings;
6.2.1.3) coefficient of balance should be smaller or equal to 4, if having in each lateral balance coefficient greater than 4, so it are made as 4, again the coefficient of balance of other windings is changed.
The above step 6.2.1) computing method of conventional transformer differential protection coefficient of balance can also be in:
Wherein, Ihe: high-pressure side secondary rated current; Uh: high-pressure side rated voltage; Nhct: high-pressure side CT no-load voltage ratio;
Ile: low-pressure side secondary rated current; Ul: low-pressure side rated voltage; Nlct: low-pressure side CT no-load voltage ratio;
With the high-pressure side is benchmark, calculates the coefficient of balance of other windings, and promptly establishing high-pressure side coefficient of balance Kh is 1, then low-pressure side coefficient of balance Kl=Ile/Ihe=(Ul * Nlct)/(Uh * Nhct).
Advantage of the present invention is:
1, analysis result is reliable, and accuracy significantly improves.Connection analysis method for conventional transformer relaying CT circuit in electric system provided by the present invention carries out twice analysis: carry out each winding connection correctness for the first time and judge, close phase for the second time; 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 system conventional transformer 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.
Description of drawings
Fig. 1 is the schematic flow sheet of relay protection of power system CT circuit connection analytical approach provided by the present invention;
Fig. 2 is for the present invention is meritorious, the idle synoptic diagram that concerns that is subjected to situation and quadrant that send.
Embodiment
The invention provides a kind of relay protection of power system CT circuit connection correctness analytical approach, the idiographic flow of wiring analysis is as follows:
1) obtains the parameter in each winding protection CT loop of conventional transformer: meritorious value, idle value and reference voltage;
Obtain the meritorious value and the idle value in each loop of conventional transformer by the transformer station of measuring loop, stoichiometric point or interrelate with it.
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.
Reference voltage: a certain voltage of measured winding is reference voltage, and this reference voltage can be phase voltage or line voltage.
2) phase place and the amplitude of each each phase current of winding protection CT loop of measurement conventional transformer:
Measure conventional phase place and the amplitude that becomes each each phase current of winding protection CT loop successively.Routine is become a certain winding, is the phasing degree that reference voltage records Ia, Ib, Ic with a certain voltage (can be phase voltage or line voltage) of this winding.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).
3) according to the calculation of parameter obtained and draw the conventional correct current phase of each CT secondary circuit that becomes:
Calculate current phase with reference to mutually according to meritorious value and idle value,, draw the current phase of other two-phases according to three-phase current phase place 120 ° and the equal-sized pacing items of amplitude each other;
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 with reference to phase power angle 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 wherein meritorious, idle send be subjected to situation and quadrant relation as shown in Figure 2, 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 equates (or the secondary current effective value of the primary current that will measure the CT loop after according to the no-load voltage ratio conversion is 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.
4) with step 2) in the correct current phase that calculates in the phase place of each each phase current of winding of conventional transformer differential protection circuit of recording and the step 3) compare, judge the correctness of tested conventional transformer differential protection circuit wiring; generate corresponding wiring state sign indicating number; the wiring state sign indicating number comprises correct wiring sign indicating number and false wiring sign indicating number, the corresponding a kind of wiring situation of each wiring state sign indicating number.
With the current phase in the protection CT loop of actual measurement with compare, judge the correctness of this protection loop CT wiring according to measuring the correct current phase that the CT loop drawn, and generate the wiring state sign indicating number of correspondence:
The implementation of wiring state sign indicating number: suppose 6 angle states earlier, and use integer representation: in the time of 0 °, status code is 0; 60 ° is 1; 120 ° is 2; 180 ° is 3; 240 ° is 4; 300 ° is 5.Then each is compared mutually, obtain the status code of its angle, do corresponding correction according to status code again.
Under the correct situation of: wiring, A is 0 ° mutually, and status code is 0, and B mutually 120, and status code is 2,240 ° mutually of C, and status code is 4; The status code that obtains this winding so is 024.The modification method of error situation and correspondence is as shown in table 1:
Table 1: the wiring kind of mistake and corresponding wiring state sign indicating number thereof
CT second protection loop to a certain winding; the phase place of each phase current measured value is deducted the reference phase power angle of calculating gained in the step 3); each phase current values after calculating is drawn its wiring state sign indicating number according to last table judgement, is the wiring result in exportable this winding CT second protection loop according to the wiring state sign indicating number.
Perhaps the phase place of actual measurement is compared according to the correct phase that the transformer station of measuring loop, stoichiometric point or interrelate with it obtains with instrument, be easy to just judge the various mistakes of wiring.Coinciding, it is correct to be wiring, can draw various judged results according to following table;
| ??A’ | ??B’ | ??C’ | ??-A’ | ??-B’ | ??-C’ | |
| ??A | Wiring is correct | B and A join instead | C and A join instead | A phase polarity connects instead | B and A join anti-and current B mutually polarity connect instead | C and A join anti-and current C mutually polarity connect instead |
| ??B | A and B join instead | Wiring is correct | C and B join instead | B and A join anti-and current | B phase polarity connects instead | B and C join anti-and current C mutually polarity connect instead |
| ??A’ | ??B’ | ??C’ | ??-A’ | ??-B’ | ??-C’ | |
| A phase polarity connects instead | ||||||
| ??C | A and C join instead | B and C join instead | Wiring is correct | A and C join anti-and current A mutually polarity connect instead | B and C join anti-and current B mutually polarity connect instead | C phase polarity connects instead |
Annotate: A ', B ', C ' are concerned definite correct phasing degree for sending according to power, A, B, the phasing degree of C for surveying.Expression is walked crosswise and is erected the value of going and equates in the grid that intersects in the form.
Draw the conventional wiring result who becomes each winding CT second protection loop successively according to preceding method.
Example: part wiring error vector plot
4.1) a phase phase place connects instead, for example certain winding B phase polarity connects shown in the anti-following table:
4.2) two-phase polarity connects instead, certain winding A for example, C phase polarity connects anti-as shown in the table:
4.3) three-phase phase connects instead, certain winding A for example, B, that C phase polarity connects inverse time is as shown in the table:
4.4) the two-phase position connects instead mutually, certain winding A for example, B joins instead, and is as shown in the table:
4.5) three phase positions connect instead mutually, for example certain winding A interlaces and receives the C phase, and C interlaces and receives the B phase, and B interlaces and receives the A phase time, and is as shown in the table:
4.6) the two-phase position connects instead mutually, wherein one mutually again polarity connect instead, for example certain winding B interlaces and receives the C phase, B phase polarity connects inverse time, and is as shown in the table:
4.7) the two-phase position connects instead mutually, third phase polarity again connects instead, and for example certain winding B interlaces and receives the C phase, and A phase polarity connects inverse time, and is as shown in the table:
4.8) the two-phase position connects instead mutually, the polarity of this two-phase also connects instead entirely, and for example certain winding A interlaces and receives the C phase, A, the polarity of C phase connects inverse time, and is as shown in the table:
4.9) the two-phase position connects instead mutually, wherein one mutually and the polarity of third phase connect inverse time, for example certain winding A interlaces and receives the B phase, the C phase connects inverse time with B polarity mutually, and is as shown in the table:
4.10) the two-phase position connects instead mutually, polarity all connects instead, and for example certain winding A interlaces and receives the C phase, and 3 phase phase places connect inverse time, and are as shown in the table:
4.11) three phase positions connect instead mutually, wherein a phase polarity connects instead, and for example certain winding A interlaces and receives the B phase, and B interlaces and receives the C phase, and C interlaces and receives the A phase, and C phase polarity connects inverse time, and is as shown in the table:
4.12) three phase positions connect instead mutually, wherein two-phase polarity connects instead, and for example certain winding A interlaces and receives the C phase, and C interlaces and receives the B phase, and B interlaces and receives the A phase, A, B phase polarity connects inverse time, and is as shown in the table:
4.13) three phase positions connect instead mutually, polarity all connects instead, and for example certain winding A interlaces and receives the B phase, and B interlaces and receives the C phase, and C interlaces and receives the A phase time, and is as shown in the table:
5) output result: according to the result who analyzes, judges each side joint line correctness of output conventional transformer.
Analysis result has two kinds: wiring is correct, and wiring error
1) if the wiring state sign indicating number of each winding is 024, then output connection is correct.
2) if it is not 024 that the wiring state sign indicating number of arbitrary winding is arranged, then output connection mistake; And according to the error situation of each winding of the table 1 in step 4) output.
6) carry out the synthetic and synthetic result of output in former and deputy limit
6.1) obtain conventional transformer differential protection route survey value and parameter:
Obtain conventional transformer differential protection circuit each winding current effective value and phase place, the i.e. current effective value and the phase place of the A of arbitrary winding, B, C, N phase by instrument measurement.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; In whole measuring process, witness mark is this voltage always, and promptly the phase place of all winding currents of conventional transformer all is the phase place with respect to this reference voltage.Reference voltage can be selected by the operator when measuring voluntarily.
Input conventional transformer differential protection line parameter circuit value before analyzing, the parameter of this transformer differential protection circuit comprises transformer connection mode, each winding CT no-load voltage ratio, each winding rated voltage, each winding power supply mode, number of switches and each winding numbering (being used to draw vector plot); Whether transformer adjusts (or each CT connection type) through the CT secondary connection; Import selected reference voltage, with reference to phase power angle (being the power angle of reference voltage place phase) from measuring the loop.
6.2) according to the conventional transformer parameter conventional transformer differential protection route survey value is converted.
6.2.1) calculate the coefficient of balance of each winding of conventional transformer
Formula one:
Have according to formula one:
Formula two is then arranged:
Wherein, S is the capacity of main transformer;
U is a winding primary side rated line voltage;
I is a winding primary side rated current;
Ie is a winding secondary rated current;
Nct is a winding CT no-load voltage ratio.
At first, calculate the secondary rated current of each winding according to above-mentioned formula two.For example in becoming, conventional transformer differential protection two circles calculate high-pressure side secondary rated current Ihe, low-pressure side secondary rated current Ile according to formula two respectively;
Then, one coefficient of balance establishing each side rated current maximum is 1, calculates the coefficient of balance of other sides.Be respectively 1000A, 5000A as Ihe, Ile, the coefficient of balance Kl that then establishes Ile is 1, then Kh=Ile/Ihe;
At last, coefficient of balance should be smaller or equal to 4 (amplifying current error if cross conference).If have in each lateral balance coefficient, so it is made as 4, again with the coefficient of balance conversion of other windings greater than 4.As above Kh, Kl are respectively 5,1, and then establishing Kh is 4, so, and Kl=1 * 4/5.
Other computing method of conventional transformer differential protection coefficient of balance:
According to formula two other computing method of can deriving.As: become for two circles, can obtain
Wherein, Ihe is a high-pressure side secondary rated current; Uh is the high-pressure side rated voltage; Nhct is a high-pressure side CT no-load voltage ratio; Ile is a low-pressure side secondary rated current; Ul is the low-pressure side rated voltage; Nlct is a low-pressure side CT no-load voltage ratio.
With the high-pressure side is benchmark, the calculated equilibrium coefficient, and promptly establishing high-pressure side coefficient of balance Kh is 1, then low-pressure side coefficient of balance Kl=Ile/Ihe=(Ul * Nlct)/(Uh * Nhct).
The coefficient of balance of each winding in the time of in like manner can calculating three circle changes or other situation.
6.2.2) according to the convert current effective value of this winding of the coefficient of balance of each winding of conventional transformer.
Each winding current be multiply by its corresponding coefficient of balance.As above in the example, then each winding (A, B, C three-phase, down with) current amplitude of surveying be multiply by its coefficient of balance, promptly enclose that change mesohigh side three-phase current amplitude multiply by Kh, low-pressure side multiply by Kl in that the conventional transformer differential protection is two.
In addition, for main transformer, if passed through the secondary connection adjustment, needing the diabolo wiring so (is Δ-1, Δ-3 ... Δ-11) winding three-phase electric current all multiply by 1.732 (i.e. 3 square roots).
6.2.3) all current phases are deducted with reference to the phase power angle;
If correct with reference to winding connection, deduct with reference to after the phase power angle for so all current phases, it should be 0 ° with reference to the phase current phase place.
6.2.4) judge whether reference voltage is Ua, if then direct execution in step 6.2.5); If not then reference voltage being converted to behind the Ua execution in step 6.2.5 again);
Reference voltage is converted to Ua:
Can select arbitrary voltage as a reference according to field condition when measuring, reference voltage might be one of Ua, Ub, Uc, Uab, Ubc, Uca so, and needing to be Ua with reference to phase transformation, to make things convenient for subsequent analysis.
According to the electric system principle 5 kinds of situations are arranged: Ua120 ° of Ub hysteresis, Ua240 ° of Uc hysteresis, Ua330 ° of Uab hysteresis, Ua90 ° of Ubc hysteresis, Ua210 ° of Uca hysteresis.
Conversion regime is: according to the reference voltage of selecting, all current phases are added that all corresponding angle gets final product.Specific as follows:
When reference voltage is Ub, be-120 ° with reference to winding A phase current phase angle, as long as each all adds 120 ° mutually to all windings, reference voltage can be converted to Ua so;
When reference voltage was Uc, A phase phase angle was-240 °, gave 240 ° of each additions of each winding.
When reference voltage was Uab, A phase phase angle was 30 °, gave 330 ° of each additions of each winding.
When reference voltage was Ubc, the A phase angle was-90 °, gave 90 ° of each additions of each winding.
When reference voltage was Uac, A phase phase angle was-210 °, gave 210 ° of each additions of each winding.
6.2.5) mode of connection of unified conventional transformer, preserve parameter and execution in step 6.3 after converting then).
This step only is used for conventional transformer differential protecting CT loop, needs the mode of connection of all windings is adjusted into identical with reference to winding in this step.For a certain winding of conventional transformer, its mode of connection has 13 kinds (Y, Δ-1, Y-2, Δ-3, Y-2, Δ-3, Y-4, Δ-5, Y-6, Δ-7, Y-8, Δ-9, Y-10, Δ-11, Y-12).Suppose that certain conventional transformer is that three circles become, the mode of connection is a Y/Y/ Δ-11, is reference voltage if select high-pressure side Ua when measuring, and then medium voltage side and low-pressure side will be adjusted into the Y wiring in this step.
The adjustment mode is: each phase phase place of winding is deducted an angle φ simultaneously.
φ＝30×(B1-B0)
Wherein, B0 is the mode of connection subscript with reference to winding, and B1 is the wiring subscript of the winding that will adjust.
As above-mentioned conventional transformer mesohigh side joint line mode is Y, then is designated as 0 under its mode of connection.The medium voltage side mode of connection is Y, then each phase current phase place of medium voltage side is all deducted 0 ° (promptly 30 * (0-0)), and the low-pressure side mode of connection is a Δ-11, so, deducts 330 ° promptly 30 * (11-0) simultaneously for low-pressure side A, B, C three-phase) it can be adjusted into the Y wiring.
6.3) according to the wiring state sign indicating number that draws in the step 4) current measured value is revised
For a certain winding, carry out reverse correction according to its wiring state sign indicating number.As the wiring state sign indicating number is 324, represents A phase polarity to connect instead, so the A phase phase place of this winding is added 180 ° and has promptly finished correction.
6.4) close mutually and export the angular difference and the difference in magnitude of former limit and secondary synthetic quantity
It is synthetic respectively mains side and load side to be carried out vector, draws former limit A, B, C three-phase and secondary A, B, C three-phase electricity flow valuve.The angular difference of more former respectively limit and secondary three-phase electricity flow valuve and difference in magnitude and output.Can further verify the analysis result of the 5th step output according to this output content.
Claims (3)
1. connection analysis method for conventional transformer relaying CT circuit in electric system, it is characterized in that: this method may further comprise the steps:
1) obtain the parameter of each winding of conventional transformer differential protection circuit: described parameter comprises meritorious value, idle value and reference voltage; Described reference voltage is a certain phase voltage or the line voltage of measured winding;
2) measure the phase place and the amplitude of each each phase current of winding of conventional transformer differential protection circuit: measure each winding Ia, Ib, Ic phase place respectively with respect to reference voltage;
3) according to the calculation of parameter obtained and draw the correct current phase of each winding secondary circuit of conventional transformer differential protection circuit: calculate current phase with reference to mutually according to meritorious value and idle value, according to three-phase current phase place 120 ° and the equal-sized pacing items of amplitude each other, draw the current phase of other two-phases;
4) with step 2) in the correct current phase that calculates in the phase place of each each phase current of winding of conventional transformer differential protection circuit of recording and the step 3) compare, judge the correctness of tested conventional transformer differential protection circuit wiring, generate corresponding wiring state sign indicating number, the wiring state sign indicating number comprises correct wiring sign indicating number and false wiring sign indicating number, the corresponding a kind of wiring situation of each wiring state sign indicating number;
5) output result: described output result comprises the correct and wiring error of wiring; If the wiring state sign indicating number of each winding is correct wiring sign indicating number, then output connection is correct; If the wiring state sign indicating number of arbitrary winding is the false wiring sign indicating number, then output connection mistake and each winding connection situation;
6) carry out the synthetic and synthetic result of output in former and deputy limit
6.1) obtain conventional transformer differential protection route survey value and parameter:
Conventional transformer differential protection route survey value comprises: the effective value of each winding current and phase place, the current effective value of described arbitrary winding are the current effective values of this winding A, B, C, N phase; The current phase of described each winding is the phase place with respect to reference voltage; Described reference voltage is the line voltage or the phase voltage of arbitrary winding;
The parameter of conventional transformer differential protection circuit comprises: the mode of connection of conventional transformer, each winding CT no-load voltage ratio, each winding rated voltage, each winding power supply mode, number of switches, whether through secondary connection adjustment and each winding numbering, with reference to the phase power angle;
6.2) according to the conventional transformer parameter conventional transformer differential protection route survey value is converted, its specific implementation is:
6.2.1) calculate the coefficient of balance of each winding of conventional transformer;
6.2.2) according to the convert current effective value of this winding of the coefficient of balance of each winding of conventional transformer;
6.2.3) all current phases are deducted with reference to the phase power angle;
6.2.4) judge whether reference voltage is Ua, if then direct execution in step 6.2.5); If not then reference voltage being converted to behind the Ua execution in step 6.2.5 again);
6.2.5) mode of connection of unified conventional transformer, preserve parameter and execution in step 6.3 after converting then)
6.3) according to the wiring state sign indicating number that draws in the step 4) current measured value is revised
For a certain winding, carry out reverse correction according to its wiring state sign indicating number;
6.4) close mutually and export the angular difference and the difference in magnitude of former limit and secondary synthetic quantity
It is synthetic respectively mains side and load side to be carried out vector, draws former limit A, B, C three-phase and secondary A, B, C three-phase electricity flow valuve, and the angular difference of more former respectively limit and secondary three-phase electricity flow valuve and difference in magnitude are also exported.
2. connection analysis method for conventional transformer relaying CT circuit in electric system according to claim 1 is characterized in that: the computing method for the coefficient of balance of conventional transformer differential protection described step 6.2.1) are:
6.2.1.1) according to formula
Calculate the secondary rated current of each winding;
6.2.1.2) one coefficient of balance establishing each winding secondary rated current maximum is 1, calculates the coefficient of balance of other windings;
6.2.1.3) coefficient of balance should be smaller or equal to 4, if having in each lateral balance coefficient greater than 4, so it are made as 4, again the coefficient of balance of other windings is changed.
3. connection analysis method for conventional transformer relaying CT circuit in electric system according to claim 1 is characterized in that: the computing method of conventional transformer differential protection coefficient of balance are described step 6.2.1):
Wherein, Ihe: high-pressure side secondary rated current; Uh: high-pressure side rated voltage; Nhct: high-pressure side CT no-load voltage ratio; Ile: low-pressure side secondary rated current; Ul: low-pressure side rated voltage; Nlct: low-pressure side CT no-load voltage ratio;
With the high-pressure side is benchmark, calculates the coefficient of balance of other windings, and promptly establishing high-pressure side coefficient of balance Kh is 1, then low-pressure side coefficient of balance Kl=Ile/Ihe=(Ul * Nlct)/(Uh * Nhct).
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| CN102608385A (en) * | 2012-02-22 | 2012-07-25 | 华为技术有限公司 | Acquiring method and device of primary side current of transformer |
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| CN112269074A (en) * | 2020-09-23 | 2021-01-26 | 上海宝冶集团有限公司 | Differential protection test method for transformer |
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| CN102608385A (en) * | 2012-02-22 | 2012-07-25 | 华为技术有限公司 | Acquiring method and device of primary side current of transformer |
| CN102608385B (en) * | 2012-02-22 | 2015-09-09 | 华为技术有限公司 | Primary side current of transformer acquisition methods and device |
| CN103743348A (en) * | 2013-02-04 | 2014-04-23 | 梁子为 | Rapid survey meter and application method thereof |
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| CN109946561A (en) * | 2019-05-13 | 2019-06-28 | 上海思源弘瑞自动化有限公司 | A kind of current transformer polarity testing method, apparatus, equipment and storage medium |
| CN109946561B (en) * | 2019-05-13 | 2022-02-18 | 上海思源弘瑞自动化有限公司 | Current transformer polarity testing method, device, equipment and storage medium |
| CN111257696A (en) * | 2020-03-03 | 2020-06-09 | 西南交通大学 | Estimation-based power transmission line fault detection method under limited PMU |
| CN111257696B (en) * | 2020-03-03 | 2021-05-04 | 西南交通大学 | Estimation-based power transmission line fault detection method under limited PMU |
| CN113820632A (en) * | 2020-06-18 | 2021-12-21 | 杭州普安科技有限公司 | Passive power secondary circuit wiring checking system and method |
| CN112269074A (en) * | 2020-09-23 | 2021-01-26 | 上海宝冶集团有限公司 | Differential protection test method for transformer |
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