CN104836330A - Method for quickly detecting bus PT three-phase disconnection of automatic switching device of standby power supply and method for preventing maloperation of bus PT three-phase disconnection of automatic switching device of standby power supply - Google Patents
Method for quickly detecting bus PT three-phase disconnection of automatic switching device of standby power supply and method for preventing maloperation of bus PT three-phase disconnection of automatic switching device of standby power supply Download PDFInfo
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Abstract
Provided are a method for quickly detecting bus PT three-phase disconnection of an automatic switching device of a standby power supply and a method for preventing maloperation of bus PT three-phase disconnection of the automatic switching device of the standby power supply. The method for quickly detecting bus PT three-phase disconnection of the automatic switching device of the standby power supply comprises following steps: when an operating inlet wire breaker is closed, if the positive-sequence voltage of the three phases of the bus PT are all lower than a bus no-voltage preset value and operating inlet wire current is higher than a certain current preset value, determining the occurrence of bus PT three-phase disconnection after performing setting and time delaying; if the positive-sequence voltage of the three phases of the bus PT are all lower than the bus no-voltage preset value and operating inlet wire PT voltage is higher than a line in-voltage preset value, determining the occurrence of bus PT three-phase disconnection; if a change ratio of the bus PT three-phase voltage is over a certain value lower than that of the operating inlet wire PT voltage, a voltage change ratio is equal to voltage effective value/voltage rated value%, and if the operating inlet wire PT voltage is higher than in-voltage preset value, determining the occurrence of bus PT three-phase disconnection. The method for quickly detecting bus PT three-phase disconnection of the automatic switching device of the standby power supply may timely discriminate bus fault about voltage lost and a bus PT three-phase disconnection fault.
Description
Technical field
The present invention relates to a kind of backup auto-activating device bus PT three-phase wire break detection method, also disclose a kind of backup auto-activating device bus PT three-phase broken string faulty action preventing method.
Background technology
Along with the up-to-dateness of our people's productive life improves day by day, people are also being doubled to the demand of electric power and degree of dependence, also more strict to the requirement of the quality of power supply, stride forward in the every field also continuous target to automation, unattended operation, Long-distance Control, uninterrupted power supply for distribution.The supply of electric power of China mainly still relies on national grid to power; electric power breach is also in continuous increase; especially serious in peak times of power consumption short of electricity phenomenon; a lot of large enterprise is all from having power plant or being equipped with generator for this reason, therefore various power supply mutual switching, ensure that the uninterrupted power supply of power supply has become the pith of protection and control loop in Modern power distribution engineering with the high reliability of power supply.
Backup auto-activating device and automatic throw-in equipment of emergency power supply, be when working power or working equipment because of exception, fault or unexpected be disconnected after, can automatically and rapidly stand-by power supply or stand-by equipment are devoted oneself to work the device that restores electricity, it is used widely in modern electric power system.
PT and voltage transformer, be used to measure the high-tension special transformer of electrical network, after high voltage can be converted to lower voltage by scale, be connected on the device such as instrument, instrument and carry out gathering or measuring, no matter voltage transformer original edge voltage is how many volts, and secondary voltage is generally all defined as 57.7 volts or 100 volts.Bus PT, is namely connected with electrical network primary equipment power bus-bar, for gathering three voltage transformers of three-phase bus voltage.Bus PT three-phase breaks, and disconnection problem appears in three voltage transformers be namely connected respectively with three-phase bus, causes it can not go out the state of bus by correct response.Bus PT voltage, namely via the busbar voltage data of voltage measuring transformer.
The criterion of the bus PT three-phase broken string that existing backup auto-activating device adopts is as follows:
1) bus positive sequence voltage be less than 30V and work inlet wire have electric current, judge that bus PT three-phase breaks;
2) bus negative sequence voltage is greater than 8V, judges bus PT single-phase or two-phase broken string.
Meet above condition arbitrarily, time delay 10 seconds report bus PT disconnection signals, after disconnection fault disappears, time delay 1.25 seconds backup auto-activating devices return pre-fault status.Meanwhile, link when backup auto-activating device provides bus PT three-phase broken string contact
accesslocking prepared auto restart loop option.
Owing to judging in the criterion whether bus PT three-phase breaks, one of them condition is that requirement work inlet wire has electric current, and when work of transformer substation inlet wire actual load electric current is too small as caused work inlet wire load current too small owing to there being small power supply to generate electricity by way of merging two or more grid systems in standing, do not reach inlet wire and have definite value in current condition, backup auto-activating device by can not judge this abnormal be that the fault of bus loss of pressure or bus PT three-phase break the wrong report of the bus loss of pressure caused, backup auto-activating device can start immediately, cause backup auto-activating device misoperation, need to introduce other criterion for this reason.
Summary of the invention
First technical problem to be solved by this invention is to provide a kind of backup auto-activating device bus PT three-phase wire break detection method, to make backup auto-activating device also can differentiate bus loss of pressure fault and bus PT three-phase disconnection fault in time when the inlet wire current that works is too small.
Second technical problem to be solved by this invention is to provide a kind of backup auto-activating device bus PT three-phase broken string faulty action preventing method, to make backup auto-activating device also can differentiate bus loss of pressure fault and bus PT three-phase disconnection fault in time when the inlet wire current that works is too small, take corresponding measure in time, thus avoid the harmful effect that backup auto-activating device misoperation causes.
The present invention solves its first technical problem by following technical solution: a kind of backup auto-activating device bus PT three-phase broken string method for quick, is characterized in that, comprise the steps:
1) PT by being connected with bus obtains bus three-phase voltage, is obtained the voltage of the arbitrary phase of work inlet wire by the PT be connected with work inlet wire, and obtains the electric current of work inlet wire by the CT be connected with work inlet wire, and work lead-in circuit breaker is when co-bit;
2) make the following judgment:
2.1) if bus PT three-phase positive sequence voltage is all less than bus no-voltage preset value, and work inlet wire current is greater than certain electric current preset value, after time delay of adjusting, judges that bus PT three-phase breaks;
2.2) if bus PT three-phase positive sequence voltage is all less than bus no-voltage preset value, and work inlet wire PT voltage is greater than circuit pressure preset value, judges that bus PT three-phase breaks;
2.3) if bus PT three-phase voltage rate of change is less than more than work inlet wire PT voltage change ratio certain value, described voltage change ratio=voltage effective value/voltage rating %, meanwhile, work inlet wire PT voltage is greater than circuit pressure preset value, judges that bus PT three-phase breaks.
Criterion 2.2) for steady-state process, criterion 2.3) in " if bus PT three-phase voltage rate of change is less than more than work inlet wire PT voltage change ratio certain value ", for transient process, criterion 2.3) in " work inlet wire PT voltage is greater than circuit pressure preset value " judge that whether busbar voltage abnormal for ensureing when the inlet wire PT voltage that works is normal, prevent because bus PT is different from circuit PT characteristic, secondary load is different, cause its measure error different, when power system voltage reduces fast, the erroneous judgement situation of bus PT three-phase voltage and the inconsistent appearance of work inlet wire PT voltage change ratio error may be caused.
Along with new forms of energy are as the continuous expansion of the promotion and application scale of photovoltaic generation, wind power generation, the load that the generation of electricity by new energy power-supply system of electric power system access causes original power generating source system to be carried there occurs change, the load current of the work inlet wire that backup auto-activating device detects may be very little, even can exceed its detection range.The appearance of these phenomenons may make some intelligent apparatus criterion as original in circuit distance protection equipment lose efficacy, and makes them cannot correctly judge the actual working state of bus-bar system, may cause erroneous judgement problem.As when the inlet wire load current that works is too small, when bus PT occurs that three-phase breaks, backup auto-activating device cannot make accurate judgment, there will be backup auto-activating device misoperation phenomenon, this may cause the accident of no-voltage of entire station to occur, by increasing criterion of the present invention, these intelligent apparatus can be made to find timely, and bus PT three-phase breaks the wrong report problem of the bus loss of pressure caused, take measures in time, as locking backup auto-activating device, avoid harmful effect.
Described step 2.2) and 2.3) in judge that bus PT three-phase broken string is as without delay operation.
Step 2) in also make the following judgment:
2.4) if bus PT three-phase voltage rate of change is identical with work inlet wire PT voltage change ratio, and be all less than certain preset value a or be all greater than certain preset value b, a<b, then judge electric power system fault;
And/or
2.5) if work inlet wire PT voltage is less than circuit pressure preset value, namely do not meet and have voltage conditions, and line voltage distribution rate of change is less than certain preset value c, but bus three-phase PT voltage is all greater than bus compression set value, namely bus has pressure, and bus PT three-phase voltage rate of change is all greater than certain preset value d, c<d, then judge that circuit PT breaks.
The present invention solves its second technical problem by following technical solution: a kind of backup auto-activating device bus PT three-phase broken string faulty action preventing method, is characterized in that, comprise the steps:
S1) PT by being connected with bus obtains bus three-phase voltage, is obtained the voltage of the arbitrary phase of work inlet wire by the PT be connected with work inlet wire, and obtains the electric current of work inlet wire by the CT be connected with work inlet wire, and work lead-in circuit breaker is when co-bit;
S2) make the following judgment:
(1) if bus PT three-phase positive sequence voltage is all less than bus no-voltage preset value, and work inlet wire current is greater than certain electric current preset value, after time delay of adjusting, judges that bus PT three-phase breaks;
(2) if bus PT three-phase positive sequence voltage is all less than bus no-voltage preset value, and work inlet wire PT voltage is greater than circuit pressure preset value, judges that bus PT three-phase breaks, locking backup auto-activating device after time delay of adjusting;
(3) if bus PT three-phase voltage rate of change is less than more than work inlet wire PT voltage change ratio certain value, described voltage change ratio=voltage effective value/voltage rating %, simultaneously, work inlet wire PT voltage is greater than circuit pressure preset value, judge that bus PT three-phase breaks, locking backup auto-activating device after time delay of adjusting.
Judge that bus PT three-phase broken string is as without delay operation in described step (2) and (3).
Relative to prior art, the present invention has following beneficial effect: 1) the invention solves new energy grid-connected power, after some current supply circuit load current diminishes, load current cannot be utilized to judge the bus PT problem whether three-phase breaks, achieve when not increasing external cabling, change by means of only software just effectively can judge PT broken string situation, effectively solves the impact that new energy grid-connected power brings;
2) the inventive method can find bus PT three-phase disconnection fault fast without time delay, and no matter be not activated all can quick lock backup auto-activating device for backup auto-activating device, improves the reliability of power system operation;
3) the inventive method adopts bus PT voltage and circuit PT voltage, bus PT voltage change ratio and circuit PT voltage change ratio to combine judgement and detects bus PT disconnection fault, do not need to add hardware device, the setting that only need complete software can realize above-mentioned functions, has the advantage of small investment instant effect;
4) namely can adaptive voltage criterion after backup auto-activating device once being adjusted, need not select to exit prepared auto restart function, improve the utilization rate of prepared auto restart, guarantee power grid security.
Accompanying drawing explanation
Fig. 1 is the main wiring diagram of network system.
Embodiment
Below in conjunction with accompanying drawing, the present invention is described in further detail:
As shown in Figure 1, threephase potential transformer is connected with bus, and the A phase of single-phase potential transformer and a circuit (only draw a circuit in figure, in fact can have many circuits) is connected, and this circuit is namely as the work inlet wire of bus.Backup auto-activating device has line voltage distribution incoming end and locked loop, is respectively used to access above-mentioned voltage transformer and locking backup auto-activating device.
For the electric power system of 110kV, 220kV electric pressure, the criterion of backup auto-activating device bus PT wire break detection method is as follows:
1) bus PT three-phase positive sequence voltage be less than 30V and work inlet wire have electric current, for judge bus PT three-phase broken string (existing criterion);
2) bus negative sequence voltage is greater than 8V, for judging bus PT single-phase or two-phase PT broken string (existing criterion);
Meet above condition time delay arbitrarily 10 seconds report bus PT disconnection faults, after disconnection fault disappears, time delay 1.25 seconds backup auto-activating devices return pre-fault status.
3) lead-in circuit breaker is worked when co-bit, bus three-phase voltage is obtained by the PT be connected with bus, the voltage of the arbitrary phase of circuit is obtained by the PT be connected with circuit, if bus PT three-phase positive sequence voltage is all less than bus no-voltage preset value, and circuit PT voltage is greater than circuit voltage preset value, then can judge that bus PT three-phase breaks without the need to time delay, locking backup auto-activating device after time delay of adjusting, prevents prepared auto restart misoperation in its simplest form.Bus PT recovers normal logic and requires same as the prior art remaining unchanged.
4) lead-in circuit breaker is worked when co-bit, bus three-phase voltage is obtained by the PT be connected with bus, the voltage of the arbitrary phase of circuit is obtained by the PT be connected with circuit, if bus PT three-phase voltage rate of change is less than more than work inlet wire PT voltage change ratio certain value, namely the difference of inlet wire PT voltage change ratio and bus PT three-phase voltage rate of change of working is more than or equal to certain value, described voltage change ratio=voltage effective value/voltage rating %, simultaneously, circuit PT voltage is greater than circuit voltage preset value, then can judge that bus PT three-phase breaks without the need to time delay, locking backup auto-activating device after time delay of adjusting, prevent prepared auto restart misoperation in its simplest form.Bus PT recovers normal logic and requires same as the prior art remaining unchanged.
The present invention goes back easily extensible and goes out following determining step:
Work lead-in circuit breaker is when co-bit, bus three-phase voltage is obtained by the PT be connected with bus, the voltage of the arbitrary phase of circuit is obtained by the PT be connected with circuit, if bus PT three-phase voltage rate of change is identical with work inlet wire PT voltage change ratio, described voltage change ratio=voltage effective value/voltage rating %, and be all less than certain preset value a or be all greater than certain preset value b, a<b, then judge the system failure.
Lead-in circuit breaker is when co-bit, bus three-phase voltage is obtained by the PT be connected with bus, obtained the voltage of the arbitrary phase of circuit by the PT be connected with circuit, if working line PT voltage is less than circuit compression set value, does not namely meet and have voltage conditions, and line voltage distribution rate of change is less than certain preset value c, but bus three-phase PT voltage is all greater than bus compression set value, and namely bus has pressure, and bus PT three-phase voltage rate of change is all greater than certain preset value d, c<d, then judge that circuit PT breaks.
Work lead-in circuit breaker is when co-bit, and when judged result is that bus PT is with no pressure, backup auto-activating device charges and in operating criterion, relevant bus has pressure and decompression criterion that employing work inlet wire PT voltage all can be selected to replace, and namely adopts single-phase voltage to determine whether pressure or low pressure.
Claims (5)
1. a backup auto-activating device bus PT three-phase broken string method for quick, is characterized in that, comprise the steps:
1) PT by being connected with bus obtains bus three-phase voltage, is obtained the voltage of the arbitrary phase of work inlet wire by the PT be connected with work inlet wire, and obtains the electric current of work inlet wire by the CT be connected with work inlet wire, and work lead-in circuit breaker is when co-bit;
2) make the following judgment:
2.1) if bus PT three-phase positive sequence voltage is all less than bus no-voltage preset value, and work inlet wire current is greater than certain electric current preset value, after time delay of adjusting, judges that bus PT three-phase breaks;
2.2) if bus PT three-phase positive sequence voltage is all less than bus no-voltage preset value, and work inlet wire PT voltage is greater than circuit pressure preset value, judges that bus PT three-phase breaks;
2.3) if bus PT three-phase voltage rate of change is less than more than work inlet wire PT voltage change ratio certain value, described voltage change ratio=voltage effective value/voltage rating %, meanwhile, work inlet wire PT voltage is greater than circuit pressure preset value, judges that bus PT three-phase breaks.
2. backup auto-activating device bus PT three-phase according to claim 1 broken string method for quick, is characterized in that, described step 2.2) and 2.3) in judge that bus PT three-phase breaks as without delay operation.
3. backup auto-activating device bus PT three-phase according to claim 2 broken string method for quick, is characterized in that, step 2) in also make the following judgment:
2.4) if bus PT three-phase voltage rate of change is identical with work inlet wire PT voltage change ratio, and be all less than certain preset value a or be all greater than certain preset value b, a<b, then judge electric power system fault;
And/or
2.5) if work inlet wire PT voltage is less than circuit pressure preset value, namely do not meet and have voltage conditions, and line voltage distribution rate of change is less than certain preset value c, but bus three-phase PT voltage is all greater than bus compression set value, namely bus has pressure, and bus PT three-phase voltage rate of change is all greater than certain preset value d, c<d, then judge that circuit PT breaks.
4. a backup auto-activating device bus PT three-phase broken string faulty action preventing method, is characterized in that, comprise the steps:
S1) PT by being connected with bus obtains bus three-phase voltage, is obtained the voltage of the arbitrary phase of work inlet wire by the PT be connected with work inlet wire, and obtains the electric current of work inlet wire by the CT be connected with work inlet wire, and work lead-in circuit breaker is when co-bit;
S2) make the following judgment:
(1) if bus PT three-phase positive sequence voltage is all less than bus no-voltage preset value, and work inlet wire current is greater than certain electric current preset value, after time delay of adjusting, judges that bus PT three-phase breaks;
(2) if bus PT three-phase positive sequence voltage is all less than bus no-voltage preset value, and work inlet wire PT voltage is greater than circuit pressure preset value, judges that bus PT three-phase breaks, locking backup auto-activating device after time delay of adjusting;
(3) if bus PT three-phase voltage rate of change is less than more than work inlet wire PT voltage change ratio certain value, described voltage change ratio=voltage effective value/voltage rating %, simultaneously, work inlet wire PT voltage is greater than circuit pressure preset value, judge that bus PT three-phase breaks, locking backup auto-activating device after time delay of adjusting.
5. backup auto-activating device bus PT three-phase broken string faulty action preventing method according to claim 4, is characterized in that,
Judge that bus PT three-phase broken string is as without delay operation in described step (2) and (3).
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| CN105244857A (en) * | 2015-10-10 | 2016-01-13 | 江苏省电力公司苏州供电公司 | Method for preventing power grid distance protection maloperation caused by voltage-losing after start-up |
| CN105244856A (en) * | 2015-09-29 | 2016-01-13 | 国家电网公司 | Method for preventing distance protection misoperation caused by PT line breakage |
| CN105891680A (en) * | 2016-06-16 | 2016-08-24 | 国网山东省电力公司滨州供电公司 | 10kV distribution line multiphase disconnection fault determination method based on three-phase voltage and current |
| CN106291219A (en) * | 2016-10-10 | 2017-01-04 | 国网四川省电力公司技能培训中心 | Single-phase earthing/PT disconnection fault automatic discrimination alarm device and method |
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| CN105244856A (en) * | 2015-09-29 | 2016-01-13 | 国家电网公司 | Method for preventing distance protection misoperation caused by PT line breakage |
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| CN105244858A (en) * | 2015-10-10 | 2016-01-13 | 江苏省电力公司苏州供电公司 | Method for preventing misoperation caused by voltage loss after starting distance protection of power grid |
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| CN105891680A (en) * | 2016-06-16 | 2016-08-24 | 国网山东省电力公司滨州供电公司 | 10kV distribution line multiphase disconnection fault determination method based on three-phase voltage and current |
| CN105891680B (en) * | 2016-06-16 | 2019-04-16 | 国网山东省电力公司滨州供电公司 | 10kV distribution line multiphase disconnection fault determination method based on three-phase voltage current |
| CN106291219A (en) * | 2016-10-10 | 2017-01-04 | 国网四川省电力公司技能培训中心 | Single-phase earthing/PT disconnection fault automatic discrimination alarm device and method |
| CN116482581A (en) * | 2023-06-20 | 2023-07-25 | 广东电网有限责任公司佛山供电局 | Transformer substation voltage transformer opening triangle voltage secondary circuit tester |
| CN116482581B (en) * | 2023-06-20 | 2023-11-14 | 广东电网有限责任公司佛山供电局 | Transformer substation voltage transformer opening triangle voltage secondary circuit tester |
| CN117526815A (en) * | 2024-01-04 | 2024-02-06 | 天津飞旋科技股份有限公司 | Power-down protection method and device for magnetic levitation motor and magnetic levitation system |
| CN117526815B (en) * | 2024-01-04 | 2024-04-02 | 天津飞旋科技股份有限公司 | Power-down protection method and device for magnetic levitation motor and magnetic levitation system |
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