CN1256539A - Microcomputer bus protection using the integration of multiple element current variables as main parameter of criterion - Google Patents
Microcomputer bus protection using the integration of multiple element current variables as main parameter of criterion Download PDFInfo
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- CN1256539A CN1256539A CN 99124111 CN99124111A CN1256539A CN 1256539 A CN1256539 A CN 1256539A CN 99124111 CN99124111 CN 99124111 CN 99124111 A CN99124111 A CN 99124111A CN 1256539 A CN1256539 A CN 1256539A
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- detecting element
- time
- fault
- bus
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Abstract
The present invention relates to the field of relaying technology for electric power system, and is mainly suitable for 6-10 KV bus of transformer station and power plant. The principle is that each power loop connected to bus has a detection element to judge bus defect based on the variation of the current waveform. The main computer determines whether the short-circuit failure is in the protected area by synthesizng the judgement of the detection elements.
Description
The present invention is a kind of distributing microcomputer type bus protection, mainly is applicable to 6～10kv bus in electric substation and power plant.The invention belongs to the relay protection of power system technical field.
The countries concerned's standard code, should be installed 6～10KV bus protection under certain condition.6～10KV bus protection of current use has two kinds of complete differential bus protection and incomplete differential bus protections.Complete differential bus protection is owing to need all be connected to the bus protective relay dish with A, the C biphase current secondary circuit of all force devices of connecting on the bus, increased the burden of secondary loop of mutual inductor, the electric current secondary loop broken string also is the unreliable factor that can not be ignored, and seldom uses in fact now; Though incomplete differential bus protection can reduce the electric current secondary loop number of guiding to the bus protective relay place, also brought the differential relay definite value to be elevated simultaneously, and the problem of non-selective tripping operation.Present 6～10KV bus protection in exploring, developing is because a variety of causes still can not be promoted the use of.
The present invention uses microcomputer to differentiate the variation of the current waveform after fault takes place, and constitutes protection system.It can react the magnitude of current of electric power system fault power circuit, bus and same other power circuits of bus, state before fault and the variation after the fault, and,, determine abort situation through calculating, comparison and logic determines according to the criterion that designs.
The present invention mainly is made up of following components: be connected in the detecting element 1 of power circuit current transformer, and main frame 2, communication network 3, the connecting line 4 between each parts is shown in figure one.Other are as follows among the figure one: 5. transformer, 6. circuit breaker, 7. current transformer.
Detecting element 1 is a single-chip microcomputer, and the magnitude of current of access is 5 amperes or 1 ampere, contains two relays, one of them actuating of relay, representative " troubles inside the sample space "; The another one actuating of relay, representative " external area error ".Constitute the node outlet, link to each other with main frame.The detecting element that is connected on the electric power incoming line loop detects the whether function of overcurrent of this loop in addition.
Main frame 2 is single-chip microcomputers, is connected with each detecting element by communication network.Can be connected with each detecting element by a pair of little bus or by cable in addition, but bi-directional information.The major function of main frame is:
A. carry out the clock synchronization calibration with each detecting element.So that record fault time, detecting element
Also need clock when making integral and calculating.
B. receiving detecting element still is the report of external area error about short trouble place-troubles inside the sample space.
C. the detecting element that comprehensively receives is made final judgement about the report in short trouble place and electric power incoming line loop overcurrent whether: be the bus troubles inside the sample space, or the bus external area error.
D. if troubles inside the sample space, then instantaneous instruction of sending " tripping operation " to the electric power incoming line loop.
E. after short trouble takes place,, send " involution " instruction to each detecting element through time-delay.
F. when electric power system normally moved, whether the operating state that detects each detecting element was normal.If find that certain detecting element work is undesired, then report to the police immediately.
3. communication network should select that speed is fast, reliability is high for use.
4. be a pair of little bus or cable.
The working method of Microcomputer Protection of the present invention is described below:
1. electric power system does not occur under the normal operating mode of short trouble.
A. initial condition, main frame and detecting element are finished the clock synchronization calibration.Main frame sends " involution " instruction.
B. detecting element current value sampling rate: 36 points/20ms.
C. detecting element detection load electric current, calculate also location:
1. sinusoidal waveform Y
A(t), Y
C(t);
2. with " 0 " point of waveform ascent stage, as the starting point of time.Determine with step calibration by host clock;
3. determine current sinusoidal T wave period (ms).；
4. refresh measured value, i.e. sinusoidal waveform at any time.
D. remember and refresh: remember and cycle of refreshing is not less than 20ms, be not more than 40ms.
When e. measuring sinusoidal wave before the fault,, or, then cancel the value of this point, replace with the mean value of 2 of front and back greater than back 1: 2 times rated current as certain any value or greater than preceding 1: 2 times rated current.
F., time quantum is set, t
0, t
1, t
2, t
3Reference value t
0～t
1=2ms, t
2～t
3=2ms, t
1～t
2Time constant by this power circuit is determined, general t
1～t
2Be 2～3 times of power circuit time constants.
2. after the fault that is short-circuited, protection starts:
A. be the start-up point by the magnitude of current 20% rated current of suddenling change.This point as (0+) after the fault first
Individual sampled point, time mark are t
0
B. the fault sampling is with normal sampling.Current value sampling rate: 36 points/20ms.
C. detecting element detection failure electric current is made the short circuit current instantaneous value to the integration of time, and the time of integration, the interval was t
0～t
1, t
2～t
3Get K
A1, K
C1, K
A2, K
C2
D. press the load current time graph of microcomputer memory, calculate A, C biphase current instantaneous value to the integration of time, the time of integration, the interval was (t
0-T
0)～(t
1-T
0), (t
2-T
0)～(t
3-T
0).Get Y
A1, Y
C1, Y
A2, Y
C2
E. according to table one, table two, to calculated value K
A1, K
C1, K
A2, K
C2And Y
A1, Y
C1, Y
A2, Y
C2Compare respectively.According to comparative result, determine that " bus protection troubles inside the sample space " still is " bus protection external area error ", and start corresponding exit relay.
F. each detecting element sends to main frame with testing result by network or cable.
G. the detecting element that comprehensively receives of main frame is made final judgement about the report in short trouble place, by table one, table two and electric power incoming line loop overcurrent whether: be the bus troubles inside the sample space, or the bus external area error.
I. if troubles inside the sample space, then instantaneous instruction of sending " tripping operation " to the electric power incoming line loop.
J. after short trouble takes place,, send " involution " instruction to each detecting element through time-delay.
K. the whether judgement of overcurrent of electric power incoming line loop: by the maximum overcurrent numerical value of actual capabilities, virtual overcurrent curve requires current phase identical with the load current phase place.Z
A2, Z
C2Be respectively A, C biphase current at time t
2～t
3Integration.
Microcomputer Protection of the present invention belongs to the distributing bus protection, and the electric current secondary loop line of each force device is received on the detecting element nearby, has alleviated the secondary burden of current transformer.This current transformer can also connect other misoperation protections.Compare with general electromagnetic relay, except have fast, sensitive characteristics, its reliability is also better, not as electromagnetic relay, any relay misoperation or tripping promptly cause the consequence of protective relaying maloperation or tripping.When being short-circuited fault, the non-fault line detecting element might not propose the report of " troubles inside the sample space " or " external area error " to main frame, still, this does not influence the judgement of main frame to position of failure point, if " troubles inside the sample space " still can normally send trip command.Table one: busbar fault
Table two: outlet fault
| The bus three-phase shortcircuit | ?K A1??Y A1?K C1??Y C1 | ?K A2??Y A2?K C2??Y C2 | Judge | Remarks |
| The R loop | ?K A1＜Y A1/1.3 ?K C1＜Y C1/1.3 | ?K A2＜Y A2/1.3 ?K C2＜Y C2/1.3 | Troubles inside the sample space | |
| The R-L loop | ?K A1＜Y A1/1.3 ?K C1＜Y C1/1.3 | ?K A2＜Y A2/1.3 ?K C2＜Y C2/1.3 | Troubles inside the sample space | |
| The R-C loop | ?K A1＞Y A1×1.3 ?K C1＞Y C1×1.3 | ?K A2＜Y A2/1.3 ?K C2＜Y C2/1.3 | Troubles inside the sample space | |
| Motor circuit | ?K A1＞Y A1×1.3 ?K C1＞Y C1×1.3 | ?K A2＜Y A2/1.3 ?K C2＜Y C2/1.3 | Troubles inside the sample space | |
| Electric power loop | ?K A1＞Y A1×1.3 ?K C1＞Y C1×1.3 | ?K A2＞Y A2×1.3 ?K C2＞Y C2×1.3 ?K A2＞Z A2×1.3 ?K C2＞Z C2×1.3 | Troubles inside the sample space | |
| Conclusion | Busbar fault |
| Three-phase shortcircuit | ?K A1??Y A1?K C1??Y C1 | ?K A2??Y A2?K C2??Y C2 | Judge | Remarks |
| The R loop | ?K A1＜Y A1/1.3 ?K C1＜Y C1/1.3 | ?K A2＜Y A2/1.3 ?K C2＜Y C2/1.3 | Troubles inside the sample space | |
| The R-L loop | ?K A1＜Y A1/1.3 ?K C1＜Y C1/1.3 | ?K A2＜Y A2/1.3 ?K C2＜Y C2/1.3 | Troubles inside the sample space | |
| The R-C loop | ?K A1＞Y A1×1.3 ?K C1＞Y C1×1.3 | ?K A2＜Y A2/1.3 ?K C2＜Y C2/1.3 | Troubles inside the sample space | |
| Motor circuit | ?K A1＞Y A1×1.3 ?K C1＞Y C1×1.3 | ?K A2＜Y A2/1.3 ?K C2＜Y C2/1.3 | Troubles inside the sample space | |
| Electric power loop | ?K A1＞Y A1×1.3 ?K C1＞Y C1×1.3 | ?K A2＞Y A2×1.3 ?K C2＞Y C2×1.3 | Troubles inside the sample space | |
| A certain branch road | ?K A1＞Y A1×1.3 ?K C1＞Y C1×1.3 | ?K A2＞Y A2×1.3 ?K C2＞Y C2×1.3 | External area error |
Claims (6)
1. criterion is the PC bus protection of main parameters with the integration of multicomponent electric current variable, it is characterized in that being connected in each force device on the bus, comprise an electric power incoming line and some load loops, a detecting element all is set, at electric power incoming line setting " main frame ", each detecting element with its magnitude of current as primary variables, before and after relatively fault takes place, A, C biphase current amount is to the integrated value of time, judge that short trouble is to occur in outside the district, or occur in the district, if the detecting element testing result of each force device all illustrates it is " troubles inside the sample space ", not having " external area error ", then is busbar fault; If it is " external area error " that the testing result of a force device is arranged, and then is not busbar fault.
2. according to claim 1 described protection, it is characterized in that being connected in the microcomputer type detecting element that each force device on the bus is provided with, its major function is:
After short trouble takes place, get two time periods, calculate each element A, C biphase current integration to the time;
Remember the position of a relative current cycle of this time period simultaneously;
Calculate the previous cycle of fault, the integration of normal operation of identical time period A, C biphase current.
3. according to claim 1 described protection, it is characterized in that if after short trouble takes place, get two time periods for example to be 2 milliseconds, 2 milliseconds at interval of two time periods, calculate k
A1, Y
A1k
C1, Y
C1k
A2, Y
A2k
C2, Y
C2, and carry out the comparison of size, according to the result of size comparison and the character of load loop, judge that short trouble belongs to " troubles inside the sample space ", still " external area error ".
4. according to claim 1 described protection, it is characterized in that its major function is as the main frame of each detecting element information of reception:
If do not receive the information of " external area error ", and electric power incoming line loop " overcurrent ", then send trip command to the electric power incoming line loop;
After short trouble took place, through time-delay, main frame sent " involution " instruction to all measuring components.
5. according to claim 1 described protection and claim 2,3,4 described features; can form another embodiment: if detecting element is judged as " external area error "; and " overcurrent "; and this force device is an end-loopback; fault should be without time-delay or delay tripping just at this power circuit so.
6. according to claim 1 described protection and claim 2,3,4, described feature; can form the 3rd embodiment: if detecting element has all been installed at electric load circuit two ends; detecting element all is judged as " external area error "; fault should be without time-delay or delay tripping just at this power circuit so.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 99124111 CN1256539A (en) | 1999-11-25 | 1999-11-25 | Microcomputer bus protection using the integration of multiple element current variables as main parameter of criterion |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 99124111 CN1256539A (en) | 1999-11-25 | 1999-11-25 | Microcomputer bus protection using the integration of multiple element current variables as main parameter of criterion |
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| Publication Number | Publication Date |
|---|---|
| CN1256539A true CN1256539A (en) | 2000-06-14 |
Family
ID=5283204
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 99124111 Pending CN1256539A (en) | 1999-11-25 | 1999-11-25 | Microcomputer bus protection using the integration of multiple element current variables as main parameter of criterion |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100424965C (en) * | 2006-11-21 | 2008-10-08 | 国网南京自动化研究院 | The communication method of the distributed PC bus protection without the main station |
| CN104009449A (en) * | 2014-05-13 | 2014-08-27 | 龙滩水电开发有限公司 | 3 kV-10 kV bus protection and failure protection method |
| CN105226619A (en) * | 2015-10-28 | 2016-01-06 | 南京新联电子股份有限公司 | The outer fault distinguishing method of distributed feeder automation district inner region |
-
1999
- 1999-11-25 CN CN 99124111 patent/CN1256539A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100424965C (en) * | 2006-11-21 | 2008-10-08 | 国网南京自动化研究院 | The communication method of the distributed PC bus protection without the main station |
| CN104009449A (en) * | 2014-05-13 | 2014-08-27 | 龙滩水电开发有限公司 | 3 kV-10 kV bus protection and failure protection method |
| CN104009449B (en) * | 2014-05-13 | 2017-05-03 | 龙滩水电开发有限公司 | 3 kV-10 kV bus protection and failure protection method |
| CN105226619A (en) * | 2015-10-28 | 2016-01-06 | 南京新联电子股份有限公司 | The outer fault distinguishing method of distributed feeder automation district inner region |
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