CN101521370A - Current differential protection relay - Google Patents
Current differential protection relay Download PDFInfo
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- CN101521370A CN101521370A CN200810214677A CN200810214677A CN101521370A CN 101521370 A CN101521370 A CN 101521370A CN 200810214677 A CN200810214677 A CN 200810214677A CN 200810214677 A CN200810214677 A CN 200810214677A CN 101521370 A CN101521370 A CN 101521370A
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- percentage differential
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/04—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for transformers
- H02H7/045—Differential protection of transformers
- H02H7/0455—Differential protection of transformers taking into account saturation of current transformers
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/22—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for distribution gear, e.g. bus-bar systems; for switching devices
- H02H7/226—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for distribution gear, e.g. bus-bar systems; for switching devices for wires or cables, e.g. heating wires
Abstract
The invention is to shorten action period without reducing reliability of the action. The invention provides a first suppression current section (16) generating a first suppression current Ires1 by adding virtual value of local terminal current I1, I2 and virtual value of the opposite terminal current Ir, also provides a second suppression current section (17) generating a second suppression current Ires1 by adding virtual value of local terminal current I1, I2 and one of virtual value of the opposite terminal current Ir or K (K>1, K is real number) times of the virtual value of the opposite terminal current Ir, in the suppression current section (17), K times of the virtual value of the opposite terminal current Ir is selected as input signal when a fist ratio differential calculation result of the opposite terminal sent from the opposite terminal has not output; the virtual value of the opposite terminal current Ir is selected as input signal when the fist ratio differential calculation result of the opposite terminal has output, a relay signal is generated to a breaker arranged on the bus connection line and is outputted when a second ratio differential calculation result of the local terminal has output.
Description
Technical field
The present invention relates to the electric power protected with power transmission line from the electric power of the bus of the transformer station that constitutes in 3/2 circuit breaker mode current differential protection relay with power transmission line, particularly with the other side's side transformer station by transmit signal receive and dispatch mutually flow through power transmission line electric current to carry out the current differential protection relay of differential protection.
Background technology
In the bus structure of power station or transformer station, having a kind of is that bus connecting line between 2 buses is provided with 2 or 3 circuit breakers, connects the bus structure (hereinafter referred to as 3/2 circuit breaker bus line structure) of 3/2 circuit breaker mode of power transmission line between each circuit breaker.Protection for the power transmission line that carries out 3/2 circuit breaker bus line structure; use current differential protection relay; electric current that this current differential protection relay obtains based on the current transformer that is provided with from the bus interface channel and the electric current that the same current transformer that is provided with obtains from the bus of the transformer station of the opposite end of power transmission line, output makes the relay action signal of circuit breaker trip.
For example; current differential protection relay in the past; the opposite end electric current that electric current that each current transformer that the bus interface channel that clip power transmission line of use from 3/2 circuit breaker bus line structure is provided with obtains and the electric current that same each current transformer that is provided with obtains from the bus of the transformer station of the opposite end of power transmission line are synthesized again; carry out the differential protection computing, the operation result of carrying out is exported as relay action signal.
If be described more specifically; then be that in the past current differential protection relay carries out differential operational and suppresses computing; this differential operational obtains each electric current that 2 current transformers being provided with from the bus connecting line that is connected with itself obtain and the effective value of the instantaneous value sum of 3 electric currents of the electric current that obtains from the electric current of the opposite end of reception (hereinafter referred to as instantaneous value and effective value (vector and effective value)); this inhibition computing is obtained 3 electric currents and is divided other effective value, obtains their each effective value sum (hereinafter referred to as effective value and (scalar sum of effective value)) simultaneously.In addition; in the past current differential protection relay use instantaneous value and effective value and effective value and; carry out the percentage differential computing; the percentage differential operation result is sent to distolateral relatively current differential protection relay; the current differential protection relay that receives this percentage differential operation result simultaneously generates relay action signal and output that the control circuit breaker is used based on the percentage differential operation result of itself and the percentage differential operation result of reception.
Current differential protection relay in the past is owing to be said structure; therefore for example; even the power transmission line external fault takes place on bus; because in a side's of 2 current transformers that link to each other with this bus the current transformer; the electric current that flows through the bus connecting line flows through with the current concentration that flows through from the opposite end through power transmission line; thereby and produce the saturated generation of current transformer spill current; at this moment also since suppress electric current be with to 3 electric currents of current differential protection relay input (from the electric current of 2 current transformers of the bus interface channel of configuration itself; and from the electric current of the current differential protection relay of opposite end) each effective value sum calculate; so can guarantee to suppress electric current, can prevent the misoperation of local terminal.
On the other hand, the electric current of the opposite end that receives is to contain the saturated resultant current of current transformer, owing to receive the opposite end electric current that equates with spill current, useless action is carried out in percentage differential computing itself though the inhibition electric current of therefore possible opposite end is little, but, therefore can prevent the useless output of relay action signal owing to obtain the percentage differential operation result of local terminal and the logic product of the percentage differential operation result that receives from the opposite end.(for example with reference to patent documentation 1.)
Patent documentation 1: 1-No. 227617 communiques of Japanese patent laid-open
Summary of the invention
Above-mentioned current differential protection relay in the past is in the output relay actuating signal; owing to need distolateral relatively percentage differential operation result; so under the situation of the internal fault that the power transmission line system for example takes place, exist from detecting the problem that fault prolonged because of the propagation delay time that obtains distolateral relatively percentage differential operation result to operate time of output relay actuating signal.In addition, the propagation delay time, the chances are several ms～tens ms, the power transmission line protection relay as requiring high speed motion has problems sometimes.
The present invention carries out in view of foregoing, and its purpose is not made reliability decrease, and the current differential protection relay that can the time under reach of action.
For solving above-mentioned problem, and achieve the goal, current differential protection relay of the present invention comprises: calculate the synthetic opposite end electric current of electric current that each home terminal current that each current transformer of being provided with from the bus connecting line that clips power transmission line of 3/2 circuit breaker bus line structure obtains and each current transformer that will be provided with from the bus connecting line that clips power transmission line of power transmission line opposite end obtain as vector and the spill current portion of the spill current represented of effective value; That calculates that the scalar sum of 3 effective values of conduct of the effective value of each effective value of described each home terminal current and described opposite end electric current represents the 1st suppresses the 1st of electric current and suppresses electric current portion; Suppress the 1st percentage differential operational part that electric current carries out the percentage differential computing, also this percentage differential operation result exported as the 1st percentage differential operation result based on described spill current and the described the 1st; And based on described the 1st percentage differential operation result, generation makes the relay action signal of the circuit breaker trip that is provided with on the described bus connecting line and the efferent of output, it is characterized in that, possess: the 2nd suppresses electric current portion, the described the 2nd suppresses electric current portion in this distolateral relatively described the 1st percentage differential operation result no-output of distolateral relatively transmission, each effective value according to described each home terminal current, multiply by the value that surpasses 1 regulation real number value with described opposite end electric current, calculate the 2nd inhibition electric current of representing as the scalar sum of these 3 effective values, when this distolateral relatively described the 1st percentage differential operation result from distolateral relatively transmission has output, each effective value according to described each home terminal current, with the effective value of described opposite end electric current, calculate the 2nd inhibition electric current of representing as the scalar sum of these 3 effective values; And based on described spill current and the described the 2nd suppress electric current carry out the percentage differential computing, and with the 2nd percentage differential operational part of this percentage differential operation result as the output of the 2nd percentage differential operation result, described efferent is exported described relay action signal when this distolateral described the 2nd percentage differential operation result has output.
If adopt the present invention, then except calculating each effective value of described each home terminal current, the 1st suppress the 1st of electric current and suppress electric current portion with the scalar sum of 3 effective values of conduct of the effective value of described opposite end electric current is represented, also possess the 2nd and suppress electric current portion, the 2nd suppresses electric current portion in this distolateral relatively described the 1st percentage differential operation result no-output of distolateral relatively transmission, each effective value according to described each home terminal current, multiply by the value that surpasses 1 regulation real number value with described opposite end electric current, calculate the 2nd inhibition electric current of representing as the scalar sum of these 3 effective values, when this distolateral relatively described the 1st percentage differential operation result from distolateral relatively transmission has output, each effective value according to described each home terminal current, with the effective value of described opposite end electric current, calculate the 2nd inhibition electric current of representing as the scalar sum of these 3 effective values.That is, the 2nd suppresses electric current portion in the 1st distolateral relatively percentage differential operation result no-output of distolateral relatively transmission, and the electric current of selecting the opposite end electric current multiply by to surpass 1 regulation real number value is as input signal; When the 1st distolateral relatively percentage differential operation result from distolateral relatively transmission has output; select opposite end electric current itself as input signal; because when this 2nd distolateral percentage differential operation result represents that output left by relay; to the circuit breaker output relay actuating signal that is provided with on the bus connecting line; so actuating signal even without the opposite end; also can the output relay actuating signal, have the reliability decrease that can not made action, can the time under reach the effect of current differential protection relay.
Description of drawings
Fig. 1 is the bus structure figure that expression is provided with 3/2 circuit breaker bus mode of the relevant current differential protection relay of this example 1.
Fig. 2 is the block diagram of the current differential protection relay of expression example 1.
Fig. 3 is the graph of a relation of the ratio of the actuating range of percentage differential computing of expression the 1st percentage differential operational part 18 and the 2nd percentage differential operational part 19 and differential current and inhibition electric current.
Fig. 4 is the block diagram of the current differential protection relay of expression example 2.
Label declaration
1,1a, 1b, 2 current differential protection relays
3 power transmission lines
4 transmit passage
9 synchronization delay portions
10,11 input current transformation components
12 input currents synthesize portion
13 received current transformation components
14 opposite end electric current K times portions
15 spill current portions
16 the 1st suppress electric current portion
17 the 2nd suppress electric current portion
18 the 1st percentage differential operational parts
19 the 2nd percentage differential operational parts
20 opposite end percentage differential operation result acceptance divisions
21 efferents (AND condition)
The 21a efferent
23 sending parts
51,52,53,54 buses
CB1, CB2, CB3, CB1r, CB2r, CB3r circuit breaker
CT1, CT2, CT1r, CT2r current transformer
Embodiment
Below, describe the example of current differential protection relay of the present invention in detail based on accompanying drawing.In addition, this example is not that the present invention is limited.
Example 1
Use Fig. 1～Fig. 3, the current differential protection relay of example 1 of the present invention is described.Fig. 1 is the bus structure figure that expression is provided with 3/2 circuit breaker bus mode of the relevant current differential protection relay of this example.Among Fig. 1, the bus structure of 3/2 circuit breaker bus mode is, on the bus connecting line of bus 51 that connects the A end and bus 52, dispose 3 circuit breaker CB1～CB3, dispose current transformer CT1 between circuit breaker CB1 and the circuit breaker CB2, dispose current transformer CT2 between circuit breaker CB3 and the bus 52; On the bus connecting line of bus 53 that connects the B end and bus 54, dispose 3 circuit breaker CB1r～CB3r, dispose current transformer CT1r between circuit breaker CB1r and the circuit breaker CB2r, dispose current transformer CT2r between circuit breaker CB3r and the bus 54; Between circuit breaker CB2 and the circuit breaker CB3, be connected with power transmission line 3 between circuit breaker CB2r and the circuit breaker CB3r; 1 input has electric current I 1, the I2 from current transformer CT1, CT2 to current differential protection relay; 2 inputs have electric current I 1r, the I2r from current transformer CT1r, CT2r to current differential protection relay, and current differential protection relay 1 and current differential protection relay 2 can communicate by transmitting passage 4 simultaneously.
The current differential protection relay 1 of A end is by carrying out the differential protection computing from the electric current I 1 of current transformer CT1, CT2, I2 with from 3 electric currents that electric current I 1r and electric current I 2r synthesized the electric current (hereinafter referred to as Ir) of (I1r+I2r) that the current differential protection relay 2 of the opposite end (B end) of power transmission line obtains; the relay action signal of output control circuit breaker CB2, CB3, protection power transmission line 3.The current differential protection relay 2 of B end carries out the differential protection computing by 3 electric currents of the electric current that electric current I 1 and electric current I 2 are synthesized that obtains from electric current I 1r, the I2r of current transformer CT1r, CT2r with from the current differential protection relay 1 of the opposite end (A end) of power transmission line; the relay action signal of output control circuit breaker CB2r, CB3r, protection power transmission line 3.
From the current differential protection relay 1 of A end, electric current I 1, I2 are home terminal current, and electric current I r is the opposite end electric current.Conversely, from the current differential protection relay 2 of B end, electric current I 1r, I2r are home terminal current, and electric current (I1+I2) is the opposite end electric current.In addition, though the electric current difference that these current differential protection relays 1,2 are imported possesses same function.
Next, the function of current differential protection relay is described with reference to Fig. 2.Fig. 2 is the block diagram of the current differential protection relay of expression example 1.Among Fig. 2, current differential protection relay 1 possesses: input current transformation component 10,11; Input current synthesizes portion 12; Synchronization delay portion 9; Received current transformation component 13; Opposite end electric current K times portion 14; Spill current portion 15; The 1st suppresses electric current portion 16; The 2nd suppresses electric current portion 17; The 1st percentage differential operational part 18; The 2nd percentage differential operational part 19; Opposite end percentage differential operation result acceptance division 20; Efferent 21 and sending part 23.
Input current transformation component 10,11 will be introduced in the current differential protection relay 1 from electric current I 1, the I2 of current transformer CT1, CT2, and is transformed to the current value of handling in the current differential protection relay.Specifically, input current transformation component 10,11 is introduced electric current I 1, I2, with 2 sides insulation of current transformer CT1, CT2, after the high order harmonic component of the electric current I 1 introduced, I2 removed, the current value of electric current I 1, I2 is transformed to the home terminal current data of digital signal.Synchronization delay portion 9 considers from propagation delay time conversion electric current I 1, the I2 of the current signal of current differential protection relay 2 notices of opposite end; electric current I 1, I2 are postponed, and making becomes current value with the moment from each current value of the current value of the electric current I r of current differential protection relay 2 notices of opposite end and electric current I 1, I2.
The synthetic portion 12 of input current will be by each home terminal current data addition (vector addition) of input current transformation component 10,11 conversion, and the electric current of addition is transferred to sending part 23 as resultant current (from the opposite end electric current of the current differential protection relay 2 of opposite end).Sending part 23 will with percentage differential operation result described later (output of the 1st percentage differential operational part 18), be sent to current differential protection relay 2 by transmitting passage 4 by the synthetic resultant current of the synthetic portion of input current 12 as transmitting signal.
Received current transformation component 13 is transformed to the opposite end electric current I r that receives the opposite end current data of handling in the current differential protection relay 1 by transmitting the opposite end electric current I r that passage 4 receives current differential protection relay 2 transmissions of opposite end.
Spill current portion 15 will be constantly by each home terminal current data of synchronous electric current I 1, I2, promptly home terminal current data I1, the I2 by 10,11 conversion of input current transformation component be corrected into into the dateout of received current (opposite end electric current I r) with synchronization delay portion 9 constantly, with the opposite end current data addition of opposite end electric current I r by 13 conversion of received current transformation component, obtain the effective value (constantly by synchronous home terminal current I1, I2 and opposite end electric current I r sum) of the electric current that current data that addition obtains represents.Here, if the effective value computing represents that with " rms " mark then the spill current Id of the operation result of spill current portion 15 is as shown in the formula expression.
Id=(I1+I2+Ir) rms ... (formula 1)
The 1st suppresses electric current portion 16 obtains the described moment of expression is received the opposite end electric current I r of current transformation portion 13 conversion by the effective value of the current data of synchronous home terminal current I1, I2 and expression the effective value of current data, with the effective value addition of obtaining separately (scalar addition), obtain the 1st and suppress electric current.Here, be I1rms if establish the effective value of electric current I 1, the effective value of electric current I 2 is I2rms, and the effective value of opposite end electric current I r is Ir_rms, and then the 1st suppresses electric current I res1 as shown in the formula expression.
Ires1=I1rms+I2rms+Ir_rms ... (formula 2)
Opposite end percentage differential operation result acceptance division 20 is by the 1st percentage differential operation result (opposite end percentage differential operation result) of the opposite end of current differential protection relay 2 transmissions of transmission passage 4 reception opposite ends.
Opposite end electric current K times portion 14 receives from the opposite end percentage differential operation result of the output of opposite end percentage differential operation result acceptance division 20, simultaneously according to the output that has or not opposite end percentage differential operation result, corresponding change is with the opposite end electric current I r of the input multiplication coefficient (setting value) that should multiply each other with this opposite end electric current I r when the 2nd suppresses 17 outputs of electric current portion.Specifically, when opposite end percentage differential operation result " has " output, with the opposite end electric current I r of input with 1 times, be that opposite end electric current I r exports the 2nd same as before to and suppresses electric current portion 17.On the other hand, in opposite end percentage differential operation result " nothing " output, doubly export the K of the opposite end electric current I r of input the to 2nd and suppress electric current portion 17.Here, the output of opposite end percentage differential operation result " has ", is meant that the 1st percentage differential operational part 18 of opposite end transmits the meaning of " logical one " to sending part 23; The output " nothing " of so-called opposite end percentage differential operation result is meant that the 1st percentage differential operational part 18 of opposite end transmits the meaning of " logical zero " to sending part 23.In addition, described multiplication coefficient K is the setting value of satisfied " K ≧ 1, K is a real number ", can use arbitrarily input unit (diagram is omitted) to set.
Here, be I1rms if establish the effective value of electric current I 1, the effective value of electric current I 2 is I2rms, and the effective value of opposite end electric current I r is Ir_rms, and then the 2nd suppresses the difference of electric current I res2 according to opposite end percentage differential operation result, can represent with following formula.
Ires2=I1rms+I2rms+K * Ir_rms ... (formula 3)
In addition, the K in (formula 3) satisfies following condition.
When (1) output of opposite end percentage differential operation result " has ": K=1
(2) during the output of opposite end percentage differential operation result " nothing ": K〉1 (K is a real number)
The 1st percentage differential operational part 18 carries out the percentage differential computing based on the spill current Id that obtains by spill current portion 15 with by the 1st inhibition electric current I res1 that the 1st inhibition electric current portion 16 obtains.The 2nd percentage differential operational part 19 carries out the percentage differential computing based on the spill current Id that obtains by spill current portion 15 with by the 2nd inhibition electric current I res2 that the 2nd inhibition electric current portion 17 obtains.
In the 1st percentage differential operational part 18 and the 2nd percentage differential operational part 19, carry out determination processing based on for example following each conditional ((condition 1)～(condition 3)).
(condition 1) Id ≧ K1
(condition 2) Id ≧ R1 * Ires
(condition 3) Id ≧ R2 * Ires+K2
In above-mentioned conditional, Id is the spill current from 15 inputs of spill current portion, Ires suppresses electric current (to suppress the 1st of electric current portion 16 inputs from the 1st and suppress electric current in the 1st percentage differential operational part 18, in the 2nd percentage differential operational part 19, suppress the 2nd of electric current portion 17 inputs and suppress electric current from the 2nd), K1, K2, R1, R2 are the setting values of the expression percentage differential computation performance for example adjusted from the outside by input unit.In order for suppressing electric current I res to become the error of big current transformer CT1, the CT2 that increases misoperation not to take place, these setting values K1, K2, R1, R2 preferably adjust to making that the percentage differential actuating range narrows down in suppressing the bigger scope of electric current I res.In addition,, consider current transformer CT1, CT2, the influence that CT1r, CT2r are saturated, generally be set at " 1 " about setting value R2.
The 1st percentage differential operational part 18 is replaced into the 1st inhibition electric current I res1 with the Ires of described (condition 1)～(condition 3), carry out the percentage differential computing, when described (condition 1)～(condition 3) all set up, the 1st percentage differential operation result of output this content of expression (conditional is all set up); When any one of described (condition 1)～(condition 3) is invalid, the 1st percentage differential operation result of output this content of expression (at least one conditional is false).
Similarly, the 2nd percentage differential operational part 19 is replaced into the 2nd inhibition electric current I res2 with the Ires of described (condition 1)～(condition 3), carry out the percentage differential computing, when described (condition 1)～(condition 3) all set up, the 2nd percentage differential operation result of output this content of expression (conditional is all set up); When any one of described (condition 1)～(condition 3) is invalid, the 2nd percentage differential operation result of output this content of expression (at least one conditional is false).
The logic product of the 1st percentage differential operation result that efferent 21 will obtain by the 1st percentage differential operational part 18 and the 2nd percentage differential operation result that obtains by the 2nd percentage differential operational part 19 exports circuit breaker CB1, CB2 to as relay action signal.Promptly, efferent 21 use the 1st suppress electric current I res1 and described (condition 1)～(condition 3) all set up and use reflection opposite end percentage differential operation result output the 2nd suppress electric current I res2 and when described (condition 1)～(condition 3) set up, the output relay actuating signal; When at least one conditional is invalid in described (condition 1)～(condition 3) using the 1st inhibition electric current I res1, perhaps use the 2nd to suppress electric current I res2 and when at least one conditional is invalid in described (condition 1)～(condition 3), not the output relay actuating signal.
Yet described (formula 1)～(formula 3) is that the spill current Id, the 1st in the current differential protection relay 1 of expression A distolateral (this distolateral) suppresses the calculating formula that electric current I res1 and the 2nd suppresses electric current I res2.Next, understand fully that spill current Idr, the 1st in the current differential protection relay 2 of B distolateral (distolateral relatively) suppresses electric current I res1r and the 2nd and suppresses electric current I res2r.
The spill current portion 15 of B end is the same with the spill current portion 15 of A end, and the effective value of obtaining home terminal current and opposite end electric current sum is as spill current.Here, each home terminal current in the current differential protection relay 2 is " electric current I 1r " and " electric current I 2r ", and the opposite end electric current is " electric current (I1+I2) ".Therefore, the spill current Idr that obtains about the spill current portion 15 of current differential protection relay 2 can be by being applicable to above-mentioned (formula 1) with these electric currents (I1r, I2r, I1, I2), with following formulate:
Idr=(I1r+I2r+I1+I2) rms ... (formula 4)
Similarly; suppress the 1st inhibition electric current I res1 that electric current portion 16 obtains about the 1st of B end (current differential protection relay 2); can be by the effective value I2r_rms of effective value I1r_rms, the home terminal current I2r of home terminal current I1r and effective value (I1+I2) rms of opposite end electric current (I1+I2) rms be applicable to (formula 2), with following formulate:
Ires1r=I1r_rms+I2r_rms+ (I1+I2) rms ... (formula 5)
On the other hand; suppress the 2nd inhibition electric current I res2 that electric current portion 17 obtains about the 2nd of B end (current differential protection relay 2); suppress electric current portion 17 because opposite end electric current I r inputs to the 2nd by opposite end electric current K times portion 14, therefore become with the 1st and suppress the different calculating formula of electric current I res1.Specifically, the 2nd suppresses electric current I res2 can be by being applicable to (formula 3) with the effective value I2r_rms of effective value I1r_rms, the home terminal current I2r of home terminal current I1r and effective value (I1+I2) rms of opposite end electric current (I1+I2) rms, with following formulate:
The rms of Ires2r=I1r_rms+I2r_rms+K * (I1+I2) ... (formula 6)
In addition, in above-mentioned (formula 6), the 1st percentage differential operational part of A end (opposite end), be the 1st percentage differential operational part 18 of current differential protection relay 1 when output " is arranged ", set K=1; The 1st percentage differential operational part 18 " nothing " when output, set and satisfy K 1 regulation real number value, as described above.
Here, carry out some supplementary notes with regard to the fault of power transmission line system.In the fault of power transmission line system, power transmission line external fault and power transmission line internal fault are arranged.The power transmission line internal fault is the interior fault that takes place of scope that current transformer CT1, CT2, current transformer CT1r, CT2r surround, and the power transmission line external fault is the fault that takes place in above-mentioned scope in addition.In addition, in these transmission line faults, current differential protection relay 1 and current differential protection relay 2 should detected fault be the power transmission line internal faults.
Next, the action with regard to the current differential protection relay of this example 1 describes.Here, at first as shown in Figure 1 in the bus structure of 3/2 circuit breaker bus mode, the power transmission line external faults take place in the scope 60 between the bus 52 of act one example explanation current transformer CT2 and A end, because this power transmission line external fault and current transformer CT1r, the CT2r of opposite end and the current transformer CT1 unsaturation of local terminal, has only the saturated situation of current transformer CT2 of local terminal.In addition, in this explanation, use " R1=0.4 ", " R2=1 " of general rate characteristic setting value R1, R2 as the actuating range of percentage differential characteristic.
In addition, for convenience of explanation, further establish electric current I 1=electric current I 2=electric current I and electric current I 1r=electric current I 2r=0.In addition, these conditions are conditions that misoperation easily takes place current differential protection relay.
When current transformer CT2 was unsaturated, by above-mentioned (formula 1), spill current Id was " 0 ".On the other hand, because power transmission line external fault and current transformer CT2 be saturated the time, by above-mentioned (formula 1), spill current Id is the value different with " 0 ".Here, suppose that electric current I 2 is 50% of actual current (electric current just often of power transmission line external fault does not take place) owing to the saturated of current transformer CT2.At this moment, notice that the direction of electric current I 1, I2 of spill current Id is opposite, by above-mentioned (formula 1), then
Id＝(I1+I2+Ir)rms
＝(I—0.5×I+0)rms
=0.5 * Irms ... (formula 7)
In addition, the side's that spill current Id/ inhibition electric current I res is bigger current differential protection relay 1 is easy to action.Therefore, imagination current differential protection relay 1 is the situation of easy action, and the effective value Ir_rms that establishes the opposite end electric current is " 0 ".
At this moment, the 1st suppresses electric current I res1 by above-mentioned (formula 2), for
Ires1＝I1rms+I2rms+Ir_rms
＝Irms+0.5×Irms+0
=1.5 * Irms ... (formula 8)
By above-mentioned (formula 7) and (formula 8), " spill current Id/ suppresses electric current I res1 " is " 1/3 ".So if setting value R1 is adjusted to " R1〉1/3 " set up, then " spill current Id/ the 1st suppresses electric current I res1＜setting value R1 ", described (condition 2) just is false.Therefore, the 1st percentage differential operational part 18 will represent that invalid the 1st percentage differential operation result of in described (condition 1)～(condition 3) at least one (being condition 2 this moment) exports sending part 23 and efferent 21 to.In addition, the 1st percentage differential operation result is sent to distolateral relatively current differential protection relay 2 by sending part 23.
Like this, a side of the input of efferent 21, input has the 1st percentage differential operation result of no-output.Therefore, the output result of efferent 21 and the 2nd percentage differential operational part 19 is irrelevant, not the output relay actuating signal.
In addition, the opposite end electric current I r of current differential protection relay 1 is home terminal current I1r, the I2r sum from current differential protection relay 2.Therefore, the spill current of the current differential protection relay 1 of described (formula 1) expression also can be represented by following formula:
Id=(I1+I2+I1r+I2r) rms ... (formula 9)
Above-mentioned (formula 4) and (formula 9) more as can be known, the spill current Idr that the spill current portion 15 of current differential protection relay 2 obtains, equated with spill current Id that the spill current portion 15 of current differential protection relay 1 obtains.Therefore, since current transformer CT2 saturated and electric current I 2 for actual current (electric current just often of power transmission line external fault does not take place) 50% the time the spill current Idr that obtains of the spill current portion 15 of current differential protection relay 2 be
Idr=Id=0.5 * Irms ... (formula 10)
Here, use the same terms when obtaining above-mentioned (formula 7), promptly use the condition of I1r_rms=I2r_rms=0, I1=I2=I.At this moment, the 1st of current differential protection relay 2 suppresses electric current I res1r by above-mentioned (formula 9), for
Ires1r＝I1r_rms+I2r_rms+(I1+I2)rms
＝0+0+(I—0.5×I)rms
=0.5 * Irms ... (formula 11)
In addition, the 2nd of current differential protection relay 2 suppresses electric current I res2r by above-mentioned (formula 6), for
Ires2r＝I1r_rms+I2r_rms+K×(I1+I2)rms
＝0+0+K×(I—0.5×I)rms
=0.5 * K * Irms ... (formula 12)
Here,, in current differential protection relay 2,, spill current Idr and the 1st equates, so " spill current Idr/ the 1st suppresses electric current I res1r=1 " because suppressing electric current I res1r by above-mentioned (formula 10) and (formula 11).Therefore, for preventing misoperation, must make " spill current Idr/ the 1st suppresses electric current I res1r〉1 " set up.Yet, because in the internal fault of single-ended input " spill current Idr/ the 1st suppresses electric current I res1r=1 ", so can't make " spill current Idr/ the 1st suppresses electric current I res1r〉1 " such the adjusting of establishment.Therefore, the 1st percentage differential operation result (output of the 1st percentage differential operational part 18) might enter the actuating range of current differential protection relay 2 and become invalid detection.That is, might described (condition 1)～(condition 3) all set up, the signal of output is arranged to a side's of efferent 21 input output.
On the other hand, as mentioned above, in current differential protection relay 1, because (condition 2) in described (condition 1)～(condition 3) is false, therefore the 1st percentage differential operation result (output of the 1st percentage differential operational part 18) is a no-output.Consequently, multiplication coefficient K is adjusted to satisfying K in described (formula 12)〉1 real number value.Here, for example be K=3 if adjust, then described (formula 12) is
Ires2r＝0.5×3×Irms
=1.5 * Irms ... (formula 13)
" spill current Idr/ the 2nd suppresses electric current I res2r=1/3 ".Therefore, by adjusting " R1〉1/3 ", can making in described (condition 1)～(condition 3) at least, (condition 2) is false.Consequently, because at the 2nd percentage differential operation result (output of the 2nd percentage differential operational part 19) of the opposing party's of efferent 21 input input no-output, so output relay actuating signal not can prevent misoperation.In addition; the 1st percentage differential operational part 18 of the current differential protection relay 1 of A end, since the state that continues to be failure to actuate, the signal of continuation output no-output; so can keep the value of described multiplication coefficient K, the current differential protection relay 2 of B end is the output relay actuating signal not.
Next, illustrate in the bus structure of 3/2 circuit breaker bus mode shown in Figure 1, for example action when current differential protection relay 1 side generation power transmission line internal fault.In addition, as the condition of action, use and above-mentioned same condition, i.e. conditions such as I1=I2=I, I1_rms=I2_rms=0, " K=3 ", " R2=1 ".
In the above-mentioned condition, the spill current Id of A end (current differential protection relay 1), the 1st suppresses electric current I res1 respectively by using above-mentioned (formula 1) and (formula 2), represents with following formula.
Id＝(I1+I2+Ir)rms
＝(I+I+0)rms
=2 * Irms ... (formula 14)
Ires1＝I1rms+I2rms+Ir_rms
＝Irms+Irms+0
=2 * Irms ... (formula 15)
Therefore, " spill current Id/ the 1st suppresses electric current I res1=1 ".Above-mentioned in order to make (condition 2) set up, and setting value R1 is adjusted to " R1＜1 " is set up.In view of the above, the 1st percentage differential operation result of A end (current differential protection relay 1) is for there being output.
In addition, the 2nd of A end (current differential protection relay 1) suppresses electric current I res2 by using above-mentioned (formula 3), represents with following formula.
Ires2＝I1rms+I2rms+3×Ir_rms
=(I+I+3 * 0) rms=2 * Irms ... (formula 16)
Therefore, " spill current Id/ the 2nd suppresses electric current I res2=1 ", the 2nd percentage differential operation result of current differential protection relay 1 also the 1st percentage differential operation result with current differential protection relay 1 is the same, for output is arranged.
Next, consider situation that the power transmission line internal fault is difficult to move.As an one example, for example consider the situation of I1=I2=I1r=I2r=I.During this condition, the spill current Id of A end (current differential protection relay 1), the 1st suppresses electric current I res1 respectively by using above-mentioned (formula 1) and (formula 2), represents with following formula.
Id＝(I1+I2+Ir)rms
＝(I+I+I+I)rms
=4 * Irms ... (formula 17)
Ires1＝I1rms+I2rms+Ir_rms
＝Irms+Irms+Irms+Irms
=4 * Irms ... (formula 18)
Therefore, " spill current Id/ the 1st suppresses electric current I res1=1 ".Above-mentioned in order to make (condition 2) set up, and setting value R1 is adjusted to " R1＜1 " is set up.In view of the above, the 1st percentage differential operation result of A end (current differential protection relay 1) is for there being output.
In addition, the 2nd of A end (current differential protection relay 1) suppresses electric current I res2 by using above-mentioned (formula 3), represents with following formula.
Ires2＝I1rms+I2rms+3×Ir_rms
=(1+1+3 * 2) Irms=8 * Irms ... (formula 19)
Therefore, " spill current Id/ the 2nd suppresses electric current I res2=4/8=1/2 ".Above-mentioned in order to make (condition 2) set up, and setting value R1 need be adjusted to being " R1＜1/2 ".In addition, in order to prevent as mentioned above in the power transmission line external fault because of the saturated misoperation that brings of current transformer CT2, setting value R1 need be adjusted is " R1〉1/3 ".So, get final product for the value (for example, any real number value of 0.35～0.45) that satisfies " 1/3＜R1＜1/2 " as long as setting value R1 is set (adjusting).By using such setting value, can detect the power transmission line internal fault, and prevent the saturated misoperation that brings owing to the current transformer CT2 of power transmission line external fault.In addition, the situation as " 3 " with the setting value K of opposite end electric current K times portion 14 has been described here, but has been not to be defined in this value, as long as the setting value of value for cooperating that can move when using the power transmission line internal fault with the power transmission line system.
Fig. 3 is the graph of a relation of the ratio of the actuating range of percentage differential computing of expression the 1st percentage differential operational part 18 and the 2nd percentage differential operational part 19 and differential current and inhibition electric current.Among Fig. 3, the longitudinal axis is represented spill current Id, and transverse axis represents to suppress electric current.In addition, the slope of the line L1 that dotted line is represented represents to be difficult to for the power transmission line internal fault ratio of " spill current Id/ suppresses electric current I res=1 " under the action situation, the line L2 that dotted line is represented represents the ratio of " spill current Id/ suppresses electric current I res=1/2 ", and the line L3 that dotted line is represented represents the ratio of " spill current Id/ suppresses electric current I res=1/3 ".In addition; the line L4 that chain-dotted line is represented represents the boundary value " spill current Id=setting value K " of above-mentioned (condition 1); the boundary value of above-mentioned (condition 2) when the line L5 that chain-dotted line is represented represents " setting value R1=0.4 " " spill current Id=setting value R1 * inhibition electric current I res "; the boundary value of above-mentioned (condition 3) when the line L6 that chain-dotted line is represented represents " setting value R2=1 " " spill current Id=setting value R2 * inhibition electric current I res+ setting value K2 ", the scope that above-mentioned (condition 1)～(condition 3) all set up becomes the actuating range of current differential protection relay 1,2.In addition, as the conditional of the 2nd percentage differential operational part 19, because as described above also as can be known, be (condition 2), therefore also can only constitute with (condition 2).
Like this, in this example 1, owing to be provided with the 1st inhibition electric current portion that generates the 1st inhibition electric current by home terminal current and opposite end electric current, with the 2nd inhibition electric current portion that generates the 2nd inhibition electric current by home terminal current and opposite end electric current, when the output of the percentage differential operation result (the 1st percentage differential operation result) of opposite end is no-output, the regulation multiplication coefficient that multiply by above 1 with this opposite end electric current replaces the opposite end electric current as input, calculate the 2nd and suppress electric current, so can obtain being difficult to carry out the percentage differential operation result of invalid action the power transmission line external fault.In addition, because when obtaining the percentage differential operation result, not as in the past, the actuating signal of wait opposite end is exported, and can move with the output of the percentage differential operation result (the 1st, the 2nd percentage differential operation result) of local terminal, so with compared because of the propagation delay time in the past, can realize high speed.
Example 2
In the current differential protection relay of example 1; used with the 1st and suppressed the 2nd different inhibition electric current portion of electric current portion; there is no-output in the 2nd inhibition electric current portion according to the percentage differential operation result of opposite end; import the corresponding opposite end electric current that multiply by the regulation multiplication coefficient, thereby obtain being difficult to carry out the percentage differential operation result of invalid action for the power transmission line external fault.In addition, in example 1, will based on the 1st suppress electric current portion output the 1st percentage differential operation result and input to efferent based on the 2nd the 2nd percentage differential operation result that suppresses the output of electric current portion, thereby obtain relay action signal.On the other hand, because in the structure of example 1, suppress in the electric current portion the 2nd, according to the output of the percentage differential operation result that has or not the opposite end and the size of the opposite end electric current of corresponding change input, so when the 2nd percentage differential operational part constituted with identical conditional with the 1st percentage differential operational part, reflection had the 1st percentage differential operation result in the opposite end for input signal.And in the structure of example 1, when the percentage differential operation result of opposite end was output as " having ", the 1st determination processing that suppresses electric current portion and the 2nd inhibition electric current portion was same result.Therefore, in the structure of example 1,, also can obtain the effect identical with example 1 even do not use the 1st percentage differential operation result for the output of relay action signal.That constitute based on such technological thought is as shown in Figure 4 current differential protection relay 1a.
In Fig. 4, current differential protection relay 1a only uses the output of the 2nd percentage differential operational part 19, and as the input of the efferent 21 of the current differential protection relay 1 of previous example 1 shown in Figure 2, this point is different.In addition, for the structure division that the current differential protection relay 1 with previous example 1 shown in Figure 2 has same function, marked same label, and the repetitive description thereof will be omitted.
If adopt the current differential protection relay of example 2; then when obtaining the percentage differential operation result; owing to be not as in the past; wait for the actuating signal and the output of opposite end; and can move with the output of the percentage differential operation result (the 1st, the 2nd percentage differential operation result) of local terminal; so with compared because of the propagation delay time in the past, can realize high speed.In addition, if adopt example 2, then with example 1 relatively owing to the logical circuit of AND circuit etc. needn't be set, therefore can make simple in structure at efferent 21.
Industrial practicality
As mentioned above, current differential protection relay of the present invention is for the power transmission line of 3/2 breaker structure Protection is useful, is specially adapted to require the system of fast-acting relay output.
Claims (2)
1. current differential protection relay comprises: calculate from being arranged at of 3/2 circuit breaker bus line structure clip each home terminal current that each current transformer of the bus connecting line of power transmission line obtains and will from being arranged at of power transmission line opposite end clip opposite end electric current that electric current that each current transformer of the bus connecting line of power transmission line obtains synthesizes as vector and the spill current portion of the spill current represented of effective value; That calculates that the scalar sum of 3 effective values of conduct of the effective value of each effective value of described each home terminal current and described opposite end electric current represents the 1st suppresses the 1st of electric current and suppresses electric current portion; Suppress the 1st percentage differential operational part that electric current carries out the percentage differential computing, also this percentage differential operation result exported as the 1st percentage differential operation result based on described spill current and the described the 1st; And, it is characterized in that possessing based on the efferent that described the 1st percentage differential operation result, the feasible relay action signal that is arranged at the circuit breaker trip of described bus connecting line of generation are also exported:
The 2nd suppresses electric current portion, the described the 2nd suppresses electric current portion under the situation of this distolateral relatively described the 1st percentage differential operation result no-output of distolateral relatively transmission, each effective value according to described each home terminal current, multiply by the value that surpasses 1 regulation real number value with described opposite end electric current, calculate the 2nd inhibition electric current of representing as the scalar sum of these 3 effective values, have under the situation of output at this distolateral relatively described the 1st percentage differential operation result from distolateral relatively transmission, each effective value according to described each home terminal current, with the effective value of described opposite end electric current, calculate the 2nd inhibition electric current of representing as the scalar sum of these 3 effective values;
And based on described spill current and the described the 2nd suppress electric current carry out the percentage differential computing, and with the 2nd percentage differential operational part of this percentage differential operation result as the output of the 2nd percentage differential operation result,
Described efferent has under the situation of output at this distolateral described the 2nd percentage differential operation result, exports described relay action signal.
2. current differential protection relay comprises: calculate from being arranged at of 3/2 circuit breaker bus line structure clip each home terminal current that each current transformer of the bus connecting line of power transmission line obtains and will from being arranged at of power transmission line opposite end clip opposite end electric current that electric current that each current transformer of the bus connecting line of power transmission line obtains synthesizes as vector and the spill current portion of the spill current represented of effective value; That calculates that the scalar sum of 3 effective values of conduct of the effective value of each effective value of described each home terminal current and described opposite end electric current represents the 1st suppresses the 1st of electric current and suppresses electric current portion; Suppress the 1st percentage differential operational part that electric current carries out the percentage differential computing, also this percentage differential operation result exported as the 1st percentage differential operation result based on described spill current and the described the 1st; And, it is characterized in that possessing based on the efferent that described the 1st percentage differential operation result, the feasible relay action signal that is arranged at the circuit breaker trip of described bus connecting line of generation are also exported:
The 2nd suppresses electric current portion, the described the 2nd suppresses electric current portion under the situation of this distolateral relatively described the 1st percentage differential operation result no-output of distolateral relatively transmission, each effective value according to described each home terminal current, multiply by the value that surpasses 1 regulation real number value with described opposite end electric current, calculate the 2nd inhibition electric current of representing as the scalar sum of these 3 effective values, have under the situation of output at this distolateral relatively described the 1st percentage differential operation result from distolateral relatively transmission, each effective value according to described each home terminal current, with the effective value of described opposite end electric current, calculate the 2nd inhibition electric current of representing as the scalar sum of these 3 effective values;
And based on described spill current and the described the 2nd suppress electric current carry out the percentage differential computing, and with the 2nd percentage differential operational part of this percentage differential operation result as the output of the 2nd percentage differential operation result,
Described efferent has output and has under the situation of output at this distolateral described the 2nd percentage differential operation result at this distolateral described the 1st percentage differential operation result, exports described relay action signal.
Applications Claiming Priority (3)
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|---|---|---|---|
| JP2008049996 | 2008-02-29 | ||
| JP2008049996A JP5068200B2 (en) | 2008-02-29 | 2008-02-29 | Current differential protection relay |
| JP2008-049996 | 2008-02-29 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101521370A true CN101521370A (en) | 2009-09-02 |
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|---|---|---|---|
| CN200810214677XA Expired - Fee Related CN101521370B (en) | 2008-02-29 | 2008-08-28 | Current differential protection relay |
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|---|---|
| JP (1) | JP5068200B2 (en) |
| KR (1) | KR100949003B1 (en) |
| CN (1) | CN101521370B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102347599A (en) * | 2011-09-20 | 2012-02-08 | 广东天富电气集团有限公司 | Protecting method for internal short-circuit current of generator |
| CN105071345A (en) * | 2015-07-31 | 2015-11-18 | 西安交通大学 | Differential protection hardware circuit with percentage differential and implementation method of differential protection hardware circuit |
| CN105899959A (en) * | 2014-03-12 | 2016-08-24 | 三菱电机株式会社 | Abnormality diagnosis device for rogowski instrument current transformer |
| CN106990381A (en) * | 2017-06-02 | 2017-07-28 | 国网江苏省电力公司宿迁供电公司 | A kind of transformer magnetic saturation detection means |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2533388B1 (en) * | 2010-02-03 | 2016-10-19 | Hitachi, Ltd. | Digital protection control system and digital protection control apparatus |
| JP5697551B2 (en) * | 2011-06-06 | 2015-04-08 | 三菱電機株式会社 | Current differential protection relay |
| JP7117963B2 (en) * | 2018-10-02 | 2022-08-15 | 三菱電機株式会社 | Protective relay device |
| JP7418245B2 (en) | 2020-03-02 | 2024-01-19 | 三菱電機株式会社 | current differential relay device |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2577424B2 (en) * | 1988-03-08 | 1997-01-29 | 関西電力株式会社 | Current differential relay method |
| JPH05137235A (en) * | 1991-11-11 | 1993-06-01 | Mitsubishi Electric Corp | Digital ratio differential relay |
| JPH05236636A (en) * | 1992-02-24 | 1993-09-10 | Fuji Electric Co Ltd | Ratio differential relay |
| JP2001095143A (en) | 1999-09-20 | 2001-04-06 | Hitachi Ltd | Current differential protective relay apparatus |
| DE10163016A1 (en) * | 2001-12-20 | 2003-07-10 | Siemens Ag | DI-guard |
| JP2004015930A (en) * | 2002-06-07 | 2004-01-15 | Toshiba Corp | Differential relay device |
| JP2004088919A (en) | 2002-08-27 | 2004-03-18 | Kansai Electric Power Co Inc:The | Current differential protective relay device |
| JP4908018B2 (en) | 2006-02-28 | 2012-04-04 | 株式会社東芝 | Current differential relay device, signal processing method thereof, and transmission line protection system |
| CN100521431C (en) * | 2006-07-05 | 2009-07-29 | 北京交通大学 | Integrated protective system based on current differential principle |
-
2008
- 2008-02-29 JP JP2008049996A patent/JP5068200B2/en not_active Expired - Fee Related
- 2008-07-14 KR KR1020080067874A patent/KR100949003B1/en not_active IP Right Cessation
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102347599A (en) * | 2011-09-20 | 2012-02-08 | 广东天富电气集团有限公司 | Protecting method for internal short-circuit current of generator |
| CN105899959A (en) * | 2014-03-12 | 2016-08-24 | 三菱电机株式会社 | Abnormality diagnosis device for rogowski instrument current transformer |
| CN105899959B (en) * | 2014-03-12 | 2018-09-04 | 三菱电机株式会社 | The apparatus for diagnosis of abnormality of Roche instrument Current Transformer |
| CN105071345A (en) * | 2015-07-31 | 2015-11-18 | 西安交通大学 | Differential protection hardware circuit with percentage differential and implementation method of differential protection hardware circuit |
| CN106990381A (en) * | 2017-06-02 | 2017-07-28 | 国网江苏省电力公司宿迁供电公司 | A kind of transformer magnetic saturation detection means |
| CN106990381B (en) * | 2017-06-02 | 2020-02-04 | 国网江苏省电力公司宿迁供电公司 | Mutual inductor magnetic saturation detection device |
Also Published As
| Publication number | Publication date |
|---|---|
| KR20090093753A (en) | 2009-09-02 |
| KR100949003B1 (en) | 2010-03-23 |
| JP2009207335A (en) | 2009-09-10 |
| CN101521370B (en) | 2012-05-23 |
| JP5068200B2 (en) | 2012-11-07 |
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