CN102385021A - Short circuit fault self-adaptive judging method - Google Patents
Short circuit fault self-adaptive judging method Download PDFInfo
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- CN102385021A CN102385021A CN201110298891XA CN201110298891A CN102385021A CN 102385021 A CN102385021 A CN 102385021A CN 201110298891X A CN201110298891X A CN 201110298891XA CN 201110298891 A CN201110298891 A CN 201110298891A CN 102385021 A CN102385021 A CN 102385021A
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Abstract
The invention relates to a short circuit fault self-adaptive judging method. The short circuit fault is judged by phase voltage and variation rate of the phase voltage. The judgment basis is formed through simultaneously meeting the three conditions as follows: the first condition: any one phase of voltage in the three phases of voltage suddenly drops; the second condition: the phase voltage dropping variation rate is greater than or equal to the variation rate threshold value; and the third condition: any one phase of voltage is lower than the short circuit fault judgment voltage threshold value. The electric system needs to maintain the balance of active power and reactive power in the whole system during the operation, when the unbalance of the active power and the reactive power occurs because some abnormal conditions occur during the operation, and the frequency or the voltage of the electric power system abnormally fluctuate and exceed the allowing range, the effective control measure needs to be adopted in time to avoid the further expansion of accidents. The method can be used for more sensitively judging the short circuit fault generated in the electric power system, the malfunction of a frequency and voltage emergency control device caused by the short circuit fault is avoided, and in addition, the method can be more preferably applicable to various types of short circuit faults of each voltage level electric network.
Description
Technical field
The invention belongs to power automation control technology field; Relate to the method that the short circuit fault self-adapting is differentiated in the power system frequency Voltage Emergency Control device; This method can be judged the short trouble that takes place in the electric system more delicately; Avoid causing the misoperation of frequency and voltage emergency control equipment, and can be applicable to all kinds short trouble of each electric pressure electrical network better because of short trouble.
Background technology
Electric system be the distribution region wide, comprise that element is many, complex structure and the fast big system of dynamic response, certain element generation disturbance of somewhere just possibly feed through to total system rapidly in the system.Power outage on a large scale appears repeatedly in the whole world in recent years, and is very big to national economy and social life influence.Therefore, the problem that keeps power system safety and stability to move has received the great attention of the parties concerned.The installing frequency and voltage emergency control equipment is raising power system safety and stability property, takes precautions against stabilization of power grids accident, prevents one of effective measures of large area blackout.Along with the expansion day by day of electric system scale, its status is apparent more important.
Electric system must keep active power and reactive power balance in the total system when operation; If having taken place when operation, some abnormal conditions cause active power or reactive power imbalance to occur; And cause frequency or the electric voltage exception fluctuation of electric system and surpass allowed band; Must take control measure timely and effectively, avoid accident further to enlarge.
When electric system reactive power deficiency occurred and causes some areas voltage to descend, the cut-out electric load was effective measures of recovering reactive balance; But the electric system failed because also possibly cause some areas voltage to descend, frequency and voltage emergency control equipment this moment locking immediately outlet, and no longer action is taked corresponding control measure according to system's reactive balance situation after waiting the short trouble excision again.Frequency and voltage emergency control equipment must correctly be distinguished the true cause that power system voltage reduces.
Traditional low pressure loadshedding equipment can't distinguish fast because the low-voltage that low-voltage that system's reactive power deficiency causes and short trouble cause; Action delay that can only be through increasing low pressure Reduction of Students' Study Load lotus is to escape short trouble; If it is shorter that this time-delay is provided with, possibly can not escape short trouble, if this time-delay is provided with longer; Then also do not wait until the action of low pressure loadshedding equipment, the voltage of electrical network collapses.
Behind electric system failed because and the protection action excision fault element; The voltage of frequency and voltage emergency control equipment installation place gos up rapidly; If recover, but recover threshold value, then frequency and voltage emergency control equipment unlocking immediately greater than voltage behind the failure removal less than normal numerical value; Allow device to excise the load of respective numbers fast, voltage is recovered.To the terminal electrical network of weak contact, the magnitude of voltage that voltage recovers after the fault maybe be lower, causes the conventional criterion possibly can't unlocking.
Summary of the invention
The objective of the invention is: for short trouble in the solution frequency and voltage emergency control equipment is differentiated problem fast; And the problem that the voltage recovery value maybe be lower behind the short circuit failure removal in the weak contact electrical network, a kind of short trouble self-adaptation method of discrimination based on phase voltage and rate of change principle thereof is proposed; Especially the new method that the short circuit fault self-adapting is differentiated in the power system frequency Voltage Emergency Control device; This method can be judged the short trouble that takes place in the electric system more delicately; Avoid causing the misoperation of frequency and voltage emergency control equipment, and can be applicable to all kinds short trouble of each electric pressure electrical network better because of short trouble.
Technical solution of the present invention is:
The method that the short-circuit fault of power system self-adaptation is differentiated adopts phase voltage and rate of change thereof to judge short trouble; This criterion is made up of three conditions:
Condition one: arbitrary phase voltage reduces suddenly in the three-phase voltage;
Condition two: (generally adjust is 100 ~ 130%Un/s) to the rate of change that phase voltage reduces greater than the rate of change threshold value;
Condition three: arbitrary phase voltage is lower than to be declared short trouble voltage threshold value (generally adjust is 70～80%Un).
Judge the method for short trouble excision back unlocking, this criterion is made up of four conditions:
Condition one: device has been judged system's failed because and the duration does not surpass " escaping fault clearing time ";
Condition two: arbitrary phase voltage raises suddenly in the three-phase voltage;
Condition three: (generally adjust is 100 ~ 130%Un/s) to the rate of change that phase voltage raises greater than the rate of change threshold value;
Condition four: three-phase voltage all is higher than to be declared short trouble recovery voltage threshold value (generally adjust is 60～80%Un).
Wherein, the Un table is system's rated voltage.
Be provided with " the short trouble voltage threshold value " of declaring short trouble and " short trouble recovery voltage threshold value " two threshold definite values of declaring failure removal respectively; Both are separate; To adapt to various dissimilar electrical networks, comprise the various short troubles of weak contact electrical network.
The change in voltage synoptic diagram is as shown in Figure 1 in electric system failed because and the short trouble excision back voltage rejuvenation; Fault takes place in a flash; Voltage drops into below " short trouble voltage threshold value " (top dotted line) fast, and short trouble continues a period of time after (generally be a few tens of milliseconds to 1 ~ 2 second, this depends on the trip time summation that adds switch the actuation time of relay protection); Short trouble is excised; The fast quick-recovery of voltage generally speaking, can return to more than " fault recovery voltage threshold value " (following dotted line).
Among Fig. 1, the rate of change the when rate of change when Du/dt1 representes the decline of instant of failure voltage, Du/dt1 are represented the recovery of failure removal transient voltage." escaping fault clearing time " is a time definite value, generally adjusts according to the principle of protecting the action maximum duration greater than reserve, and for example: if the back-up protection maximum duration is 4 seconds, then Tfc can be made as 4.5～5 seconds.
Beneficial effect of the present invention: the fault overwhelming majority that electric system takes place is an asymmetric fault; The sudden change amount of three-phase voltage and unequal during fault; Because the present invention adopts phase voltage and phase voltage rate of change to judge short trouble, has higher sensitivity so the present invention judges short trouble.The present invention adopts phase voltage and phase voltage rate of change to judge short trouble excision back unlocking in addition, has higher sensitivity than classic method.
Description of drawings
Unlocking synoptic diagram behind locking of Fig. 1 short-circuit fault of power system and the failure removal;
Fig. 2 differentiates logic diagram based on the short trouble of phase voltage rate of change;
Fig. 3 differentiates logic diagram based on the short trouble excision back unlocking of phase voltage rate of change.
Embodiment
The PCS-994 series frequency and voltage emergency control equipment of producing with Nanrui Jibao Electric Co., Ltd is an example; During normal operation, this device is kept watch on the every phase voltage and the rate of change thereof of each section bus of access device always, and device can select wherein one section busbar voltage as judgement voltage according to the voltage condition of every section bus; If arbitrary situation then was judged to system's failed because below this section busbar voltage took place; Locking low pressure Load Alleviation Function, as shown in Figure 2, the implementation method explanation as follows in detail.
Situation 1:A phase voltage is judged the criterion of system's failed because:
Situation 2:B phase voltage is judged the criterion of system's failed because:
Situation 3:C phase voltage is judged the criterion of system's failed because:
As shown in Figure 3, then unlocking simultaneously meets the following conditions in " escaping fault clearing time " behind the short circuit blocking:
(1) three-phase voltage all is higher than short trouble recovery voltage threshold value
(2) arbitrary phase voltage rises and rate of change >=rate of change threshold value,
Wherein (2) some implementation method is following:
Or
Or
In the formula 1～6, it is 100 ~ 130%Un/s that the voltage change ratio threshold value is generally adjusted, and it is 70～80Un/s that short trouble voltage threshold value is generally adjusted, and it is 60～80Un/s that short trouble recovery voltage threshold value is generally adjusted, and wherein Un representes system's rated voltage.
Claims (3)
1. the method differentiated of a short trouble self-adaptation is characterized in that: adopt phase voltage and rate of change thereof to judge short trouble, satisfied simultaneously by following three conditions and form criterion:
Condition one: arbitrary phase voltage reduces suddenly in the three-phase voltage;
Condition two: the rate of change that phase voltage reduces is more than or equal to the rate of change threshold value;
Condition three: arbitrary phase voltage is lower than declares short trouble voltage threshold value.
2. the method that a kind of short trouble self-adaptation as claimed in claim 1 is differentiated is characterized in that: the unlocking criterion is formed by four conditions are satisfied simultaneously after judging the short trouble excision:
Condition one: device has been judged system's failed because and the duration does not surpass " escaping fault clearing time ";
Condition two: arbitrary phase voltage raises suddenly in the three-phase voltage;
Condition three: the rate of change that phase voltage raises is greater than the rate of change threshold value;
Condition four: three-phase voltage all is higher than declares short trouble recovery voltage threshold value.
3. the method differentiated of according to claim 1 or claim 2 a kind of short trouble self-adaptation; It is characterized in that: described " short trouble voltage threshold value " is two separate threshold values with " short trouble recovery voltage threshold value ", is applicable to the various short troubles of weak contact electrical network.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102818972A (en) * | 2012-08-30 | 2012-12-12 | 天津大学 | Microgrid failure locating method |
| CN103280781A (en) * | 2013-05-07 | 2013-09-04 | 清华大学 | Fault self-healing method for neutral point effective earthing system |
| CN110176768A (en) * | 2018-07-17 | 2019-08-27 | 吴怀诚 | A kind of electric power data analysis method |
| CN110365030A (en) * | 2019-08-09 | 2019-10-22 | 武汉能众科技有限公司 | A kind of new energy fast frequency response control apparatus |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101329381A (en) * | 2008-07-28 | 2008-12-24 | 庞元俊 | Method for detecting short circuit fault with current change rate |
| CN101345421A (en) * | 2008-08-19 | 2009-01-14 | 国网电力科学研究院 | Method for implementing frequency voltage emergency control of power system |
| CN101826727A (en) * | 2010-05-11 | 2010-09-08 | 国网电力科学研究院 | Method for realizing emergency control on frequency and voltage of electric system |
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2011
- 2011-09-28 CN CN201110298891XA patent/CN102385021A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101329381A (en) * | 2008-07-28 | 2008-12-24 | 庞元俊 | Method for detecting short circuit fault with current change rate |
| CN101345421A (en) * | 2008-08-19 | 2009-01-14 | 国网电力科学研究院 | Method for implementing frequency voltage emergency control of power system |
| CN101826727A (en) * | 2010-05-11 | 2010-09-08 | 国网电力科学研究院 | Method for realizing emergency control on frequency and voltage of electric system |
Non-Patent Citations (1)
| Title |
|---|
| 南京南瑞继保电气有限公司: "《RCS-994C频率电压紧急控制装置技术和使用说明书》", 15 July 2010 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102818972A (en) * | 2012-08-30 | 2012-12-12 | 天津大学 | Microgrid failure locating method |
| CN103280781A (en) * | 2013-05-07 | 2013-09-04 | 清华大学 | Fault self-healing method for neutral point effective earthing system |
| CN110176768A (en) * | 2018-07-17 | 2019-08-27 | 吴怀诚 | A kind of electric power data analysis method |
| CN110365030A (en) * | 2019-08-09 | 2019-10-22 | 武汉能众科技有限公司 | A kind of new energy fast frequency response control apparatus |
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Application publication date: 20120321 |