CN102298115A - Method for online monitoring and analyzing adjustment performance of excitation system based on phasor measurement technology - Google Patents

Abstract

The invention discloses a method for online monitoring and analyzing adjustment performance of an excitation system based on a phasor measurement technology. The method comprises the following steps of: (1) online monitoring change conditions of key electric parameters, such as terminal voltage/current, excitation voltage and the like by utilizing real-time PMU (Power Management Unit) data of a machine set collected by a phasor measurement unit and the excitation system thereof, and detecting disturbance generation of the machine set and adjustment action response of the excitation system in real time; and (2) analyzing dynamic behaviour characteristics of the excitation system of a computing machine set in a disturbance process in real time, wherein the dynamic behaviour characteristics include parameters, such as disturbance occurrence time, a maximum value of excitation voltage/current and occurrence time thereof, terminal voltage steady time, voltage static adjustment rate before/after disturbance, excitation voltage multiple, voltage response time of the excitation system, voltage transient adjustment rate and the like. The method disclosed by the invention can be operated online and can be used for testing conveniently without special requirement limitation. The method can be applied to carrying out online detection, analysis and evaluation reference of the dynamic adjustment performance of the operated excitation system.

Description

Excitation system adjusting function in-service monitoring analytical approach based on phasor measuring technique

Technical field

The invention belongs to the electric power network technique field, relate to a kind of in-service monitoring analytical approach of generator excited system adjusting function more precisely, particularly a kind of excitation system adjusting function in-service monitoring analytical approach based on phasor measuring technique.

Background technology

Generator excited system is as the important control unit of synchronous generator, and its dynamic adjustments performance has direct influence to the stability and the reliability of generator and Operation of Electric Systems.At present, in order to analyze and assess the performance of excitation system, simultaneously, disturb for fear of electrical network normally being moved form, conventional method of testing all is by the independent off-line testing of excitation system is carried out, this not only needs a large amount of preliminary preparations and can not often carry out, and testing method to test with the intensity of disturbing signal and the specific limited requirement of action time, also cause some test result can not reflect dynamic response characteristic in the excitation system actual motion fully.

Simultaneously, the performance requirement to excitation system has proposed clear and definite evaluation criterion in the administrative provisions that are incorporated into the power networks of current power scheduling mechanism generating plant in its compass of competency.And at present the performance parameter index of unit excitation system substantially all is to be reported voluntarily by the generating plant, by operational management mechanism it is estimated again, and such evaluation method and result obviously lack accuracy.So, in order to make net economize the practical adjustments performance that scheduling mechanism could estimate and examine each generating plant unit excitation system more accurately, just require management organization that generating plant excitation system performance is had more active, monitoring and evaluation means directly perceived and effective.

Along with based on the development gradually of the phasor measuring technique of GPS (GPS) with ripe, and the widespread use of this technology in wide area phasor measurement system (WAMS), make a large amount of high-density samplings, target unit and the real-time PMU dynamic data of excitation system thereof can unify to deliver to the provincial dispatching center of net system when same, this is just for realizing that the management and running layer is to the on-line monitoring of the Power Plant excitation system adjusting function of actual motion with estimate examination and provide the foundation.

Summary of the invention

Technical matters to be solved by this invention is: the shortcoming that overcomes prior art and methods, provide a kind of simple and convenient, no specific (special) requirements restriction can detect, analyze and estimate the examination reference to the actual dynamic adjustments performance of excitation system in service by real-time online.

The technical solution adopted for the present invention to solve the technical problems is as follows:

A kind of excitation system adjusting function in-service monitoring analytical approach based on phasor measuring technique is characterized in that: may further comprise the steps:

1) unit and the real-time PMU data of excitation system thereof of utilizing phasor measurement unit to gather, the situation of change of crucial electric parameters such as in-service monitoring set end voltage/electric current, field voltage, detect the generation of unit disturbance and the response that excitation system is regulated action thereof in real time: extract real-time unit set end voltage/current data, calculate and judge that their variable quantities in preset time surpass the corresponding threshold value of setting and determine that unit is disturbed; Simultaneously, after accurately detecting the unit disturbance, whether its corresponding field voltage variation tendency of discriminatory analysis meets the actual physics response condition of this time disturbance correspondence, and determines the excitation system action according to the field voltage variable quantity above setting threshold;

2) under the situation that detects this time unit disturbance excitation system adjusting action, the dynamic behaviour characteristic of real-time analysis computer set excitation system in perturbation process, mainly comprise the maximal value of disturbance time of occurrence, field voltage/electric current and time of occurrence thereof, set end voltage stabilization time, the static regulation of the front/rear voltage of disturbance, field voltage multiple, parameters such as excitation system voltage responsive time, voltage transient regulation.Major parameter is specifically determined and is calculated as follows:

21) set end voltage stabilization time

By judging that the back continuous T takes place in disturbance _nThe difference of maximum voltage and minimum voltage is no more than voltage recovery dead zone range (generally get rated voltage 0.3%) and determines voltage recovery time within second (can be provided with, generally be taken as 5 seconds), and gets T _nEntering voltage recovery dead zone range in second first is that set end voltage recovers constantly constantly.

Being provided with maximum voltage limit value release time simultaneously during actual engineering is handled is 20s (low-frequency oscillation is generally between 0.2-2.5Hz), if cumulative time time that i.e. disturbance takes place constantly to be experienced the finish time with present judgement disturbance surpasses the 20s range of voltages and recovers as yet, force then to think that disturbance finishes, and get the set end voltage recovery and put in order in the 20th second the back constantly for the disturbance generation constantly.

22) voltage regulation accuracy computing formula:

${\mathrm{\δ}}_{\mathrm{stu}}=\frac{\max \left\{\right|U_{\max }-U_{\mathrm{ave}}|,|U_{\min }-U_{\mathrm{abe}}\left|\right\}}{U_N}\×100\%---\left(1\right)$

In the formula: δ _StuBe voltage regulation accuracy, U _MaxBe calculation interval T _sInterior maximum voltage, U _MinBe calculation interval T _sInterior minimum voltage, U _AveBe calculation interval T _sInterior average voltage, U _NBe the set end voltage ratings.

Voltage regulation accuracy calculates and to be divided into before the disturbance voltage regulation accuracy behind the voltage regulation accuracy and disturbance, to get rid of the perturbation process voltage jump period calculates accuracy to voltage regulation accuracy influence.

Calculate for voltage regulation accuracy before the disturbance: calculation interval T _sFor t constantly takes place in this disturbance ₁Preceding T _sSecond.Simultaneously, if time interval T constantly takes place to this disturbance the finish time in last disturbance _Diff＜Ts, then T _sBe taken as T _Diff

Calculate for voltage regulation accuracy after the disturbance: calculation interval T _sBe this disturbance t finish time ₂Back T _sSecond.Simultaneously, if time interval T constantly takes place to disturbance next time the finish time in this disturbance _Diff＜T _s, T then _sBe taken as T _Diff

23) voltage transient regulation

${\mathrm{\Δ}}_p=\frac{|U_s-U_d|}{U_N}\×100\%---\left(2\right)$

In the formula: Δ _pBe voltage transient regulation, U _sBe set end voltage amplitude before the disturbance, U _dBe set end voltage amplitude after the disturbance, U _NBe unit rated voltage amplitude, U _dBe taken as T after disturbance finish time _nThe mean value of voltage in second.

24) field voltage multiple

Field voltage multiple (excitation forcing ratio) K _FpBe meant the maximum excitation system voltage U that occurs in the perturbation process _FpWith the rated excitation voltage U _FNThe ratio, that is:

$K_{\mathrm{fp}}=\frac{U_{\mathrm{fp}}}{U_{\mathrm{fN}}}---\left(3\right)$

Regulate action for excitation system and be the adjusting of excitation reduction, do not carry out this calculation of parameter.

25) the excitation system voltage responsive time

Excitation system voltage responsive time T _gBe meant that the excitation system output voltage reaches maximum voltage U _FpWith the rated excitation voltage U _FNDifference 95% required time the second number.

In concrete actual treatment, adopt approach based on linear interpolation accurately to determine excitation system voltage responsive time T for real-time PMU discrete data point _g

Regulate action for excitation system and be the adjusting of excitation reduction, do not carry out this calculation of parameter.

The beneficial effect that the present invention reached:

Adopt the inventive method, can realize that real-time online catches the generation of unit voltage/current disturbance automatically and judge excitation system practical adjustments action situation, the dynamic adjustments performance of excitation system in the analytical calculation actual motion.Remedying conventional method can only carry out experimental test by off-line, needs a large amount of preliminary works before the test, and to the intensity of disturbing signal with artificial restriction is arranged action time, and test result can not reflect the shortcoming of the actual dynamic response characteristic of excitation system fully.The benefit of the inventive method is on-line operation, convenient test, no specific (special) requirements restriction, can be used for operating excitation system dynamic adjustments performance is carried out online check and analysis and evaluation reference.

Description of drawings

Fig. 1 is excitation system adjusting function in-service monitoring analysis principle figure.

Embodiment

With reference to the accompanying drawings and in conjunction with the embodiments the present invention is described in further detail.But the invention is not restricted to given example.

This example has comprised a unit set end voltage decline disturbance, and the response process that excitation system voltage rises and regulates adopts method online in real time of the present invention to detect and the adjustment of field excitation dynamic property characteristic of calculating in the perturbation process.

U is a generator terminal voltage among Fig. 1, and I is a generator machine end electric current, U _fBe field voltage, I _fBe exciting current.

(1) unit Disturbance Detection and excitation response action situation are judged

Disturbance Detection computing formula: Δ U (t ₁)=(U (t ₁)-U (t ₁+ Δ t))/U (t ₁) (4)

ΔI(t ₁)＝I(t ₁+Δt)-I(t ₁) (5)

The excitation response action is judged:

ΔU _f(t ₁)＝(U _fP-U _f(t ₁))/U _f(t ₁) (6)

At first, utilize formula (4) to current time t ₁The set end voltage rate of change Δ U (t that its subsequent perturbations judges that time limit scope (0.2 second) is interior is calculated in pointwise ₁), when calculating detects t5 set end voltage rate of change Δ U (t constantly ₁) when the situation greater than voltage disturbance threshold value (0.5%) occurring, then use (5) formula to calculate machine end current changing rate Δ I (t in the corresponding time limit scope immediately ₁) whether satisfy greater than corresponding current disturbance threshold value (100A), if the variation of machine end electric current also reaches the requirement of disturbance limit value, utilize (6) formula to calculate t again ₁The maximum variation delta U of the interior field voltage of time limit scope (2 seconds) is judged in constantly follow-up excitation response _f(t ₁) whether satisfy greater than the disturbance threshold value of setting (3%), think that if above-mentioned disturbance threshold situation is all satisfied this unit disturbance takes place and regulate action at its excitation system of this time disturbance, actual physics response condition according to excitation system is judged as excitation behavior (corresponding set end voltage rising simultaneously, the response condition that disturbance that electric current descends and field voltage reduce, be judged as the excitation reduction behavior), and write down this disturbance t takes place to be constantly ₁

(2) under the situation that detects the action of unit disturbance generation and adjustment of field excitation, calculate the adjustment of field excitation performance parameter in this perturbation process.

At first, be t constantly detecting unit disturbance generation ₁After, search and write down field voltage maximal value U in excitation amount window search time (2 seconds) scope after disturbance takes place _FPAnd go out t now ₃, exciting current maximal value I _FPAnd go out t now ₄, substitution then (7) formula is calculated field voltage multiple (excitation forcing ratio) K _Fp

$K_{\mathrm{fp}}=\frac{U_{\mathrm{fp}}}{U_{\mathrm{fN}}}---\left(7\right)$

U in the formula _FNBe rated excitation voltage.

Because real time data is the discrete sampling point of constant duration, here adopts and come meticulous definite excitation system output voltage to reach the moment f of ratings real-time field voltage data approach based on linear interpolation ₆, and reach maximum voltage U _FpWith the rated excitation voltage U _FNDifference 95% constantly, i.e. (U _Fp-U _FN) * 95% a corresponding position t constantly ₇, and excitation system voltage responsive Time Calculation is:

T _g＝t ₇-t ₆ (8)

Regulate action for excitation system and be the adjusting of excitation reduction, so do not carry out the calculating of excitation system voltage responsive time and ceiling voltage multiple owing to do not exist top value field voltage not need.

T constantly takes place from disturbance ₁Beginning is by real-time judge voltage recovery time window T _nThe difference of maximum voltage and minimum voltage is no more than voltage recovery dead band value (specified set end voltage 0.3%) and determines voltage recovery time within second scope (generally being taken as 5 seconds), and gets current T _nThe moment that enters voltage recovery dead band in second first is that set end voltage recovers constantly, as the moment t among Fig. 1 ₂Be provided with maximum voltage limit value release time during actual engineering is handled simultaneously and be 20s (in view of low-frequency oscillation generally between 0.2-2.5Hz), if the cumulative time that i.e. disturbance takes place constantly to be experienced the finish time with present judgement disturbance surpasses the 20s range of voltages and recovers as yet, then pressure thinks that disturbance finishes, and gets set end voltage and recover moment back to take place the 20th second for disturbance constantly.

Recover t constantly at definite set end voltage ₂After, with T after disturbance finish time _nSecond, scope was used formula (9) calculating voltage transient state regulation:

${\mathrm{\Δ}}_p=\frac{|U_s-U_d|}{U_N}\×100\%---\left(9\right)$

In the formula: Δ _pBe voltage transient regulation, U _sBe set end voltage amplitude before the disturbance, just the U (t here ₁), U _dBe set end voltage amplitude after the disturbance, can be taken as T after disturbance finish time _nThe mean value of voltage in second, U _NBe the unit rated voltage amplitude.

Recover t constantly at definite set end voltage ₂After, can further utilize formula (10) calculating voltage degree of regulation (being divided into before the disturbance and voltage regulation accuracy after the disturbance) as follows:

${\mathrm{\δ}}_{\mathrm{stu}}=\frac{\max \left\{\right|U_{\max }-U_{\mathrm{ave}}|,|U_{\min }-U_{\mathrm{abe}}\left|\right\}}{U_N}\×100\%---\left(10\right)$

In the formula: δ _StuBe voltage regulation accuracy, U _MaxBe voltage regulation accuracy time window T _sMaximum voltage in (generally being taken as 10 seconds), U _MinBe voltage regulation accuracy time window T _sInterior minimum voltage, U _AveBe corresponding calculation interval T _sInterior average voltage, U _NBe the set end voltage ratings.

Calculate for voltage regulation accuracy before the disturbance: calculation interval T _sFor t constantly takes place in this disturbance ₁Preceding T _sSecond.Simultaneously, if the time interval constantly takes place to this disturbance the finish time in last disturbance _Tdiff＜T _s, T then _sBe taken as T _Diff

Calculate for voltage regulation accuracy after the disturbance: calculation interval T _sBe this disturbance t finish time ₂Back T _sSecond.Simultaneously, if time interval T constantly takes place to disturbance next time the finish time in this disturbance _Diff＜T _s, T then _sBe taken as T _Diff

Below disclose the present invention with preferred embodiment, so it is not in order to restriction the present invention, and all employings are equal to replaces or technical scheme that the equivalent transformation mode is obtained, all drops within protection scope of the present invention.

Claims (4)

1. based on the excitation system adjusting function in-service monitoring analytical approach of phasor measuring technique, it is characterized in that: may further comprise the steps:

1) unit and the real-time PMU data of excitation system thereof of utilizing phasor measurement unit to gather, the situation of change of the crucial electric parameters of in-service monitoring, detect the generation of unit disturbance and the response that excitation system is regulated action thereof in real time, described crucial electric parameters comprises set end voltage/electric current, field voltage;

2) the dynamic behaviour characteristic of real-time analysis computer set excitation system in perturbation process comprises the maximal value of disturbance time of occurrence, field voltage/electric current and time of occurrence thereof, set end voltage stabilization time, the static regulation of the front/rear voltage of disturbance, field voltage multiple, excitation system voltage responsive time and voltage transient regulation.

2. the excitation system adjusting function in-service monitoring analytical approach based on phasor measuring technique according to claim 1, it is characterized in that: in described step 1), by extract real-time unit set end voltage/electric current PMU data, calculate and judge that the unit set end voltage/variable quantity of electric current PMU data in preset time surpasses the corresponding threshold value of setting and determine that unit is disturbed; After accurately detecting the unit disturbance, whether its corresponding field voltage variation tendency of discriminatory analysis meets the actual physics response condition of this time disturbance correspondence, and determines the excitation system action according to the field voltage variable quantity above setting threshold.

3. the excitation system adjusting function in-service monitoring analytical approach based on phasor measuring technique according to claim 1, it is characterized in that: in described step 2) in, under the situation that detects this time unit disturbance excitation system adjusting action, extract and record disturbance time of occurrence, the maximal value of field voltage/electric current and time of occurrence thereof, and the control characteristic of excitation system calculated, comprise set end voltage stabilization time, the static regulation of the front/rear voltage of disturbance, the voltage transient regulation, field voltage multiple and excitation system voltage responsive time, concrete determine and be calculated as follows:

21) set end voltage stabilization time

By judging that the back continuous T takes place in disturbance _nThe difference of maximum voltage and minimum voltage is no more than voltage recovery dead zone range and determines voltage recovery time within second, and gets T _nEntering voltage recovery dead zone range in second first is that set end voltage recovers constantly constantly;

22) voltage regulation accuracy computing formula:

${\mathrm{\δ}}_{\mathrm{stu}}=\frac{\max \left\{\right|U_{\max }-U_{\mathrm{ave}}|,|U_{\min }-U_{\mathrm{abe}}\left|\right\}}{U_N}\×100\%---\left(1\right)$

In the formula: δ _StuBe voltage regulation accuracy, U _MaxBe calculation interval T _sInterior maximum voltage, U _MinBe calculation interval T _sInterior minimum voltage, U _AveBe calculation interval T _sInterior average voltage, U _NBe the set end voltage ratings, voltage regulation accuracy calculates and to be divided into before the disturbance voltage regulation accuracy behind the voltage regulation accuracy and disturbance;

23) voltage transient regulation

${\mathrm{\Δ}}_p=\frac{|U_s-U_d|}{U_N}\×100\%---\left(2\right)$

In the formula (2): Δ _pBe voltage transient regulation, U _sBe set end voltage amplitude before the disturbance, U _dBe set end voltage amplitude after the disturbance, U _NBe unit rated voltage amplitude, U _dBe taken as T after disturbance finish time _nThe mean value of voltage in second;

24) field voltage multiple

Field voltage multiple K _FpBe meant the maximum excitation system voltage U that occurs in the perturbation process _FpWith the rated excitation voltage U _FNThe ratio, that is:

$K_{\mathrm{fp}}=\frac{U_{\mathrm{fp}}}{U_{\mathrm{fN}}}---\left(3\right)$

Regulate action for excitation system and be the adjusting of excitation reduction, so owing to do not exist top value field voltage not need to carry out this calculation of parameter;

25) the excitation system voltage responsive time

Excitation system voltage responsive time T _gBe meant that the excitation system output voltage reaches maximum voltage U _FpWith the rated excitation voltage U _FNThe second number of 95% required time of difference, adopt approach based on linear interpolation accurately to determine excitation system voltage responsive time T for real-time PMU discrete data point _g, regulate action for excitation system and be the adjusting of excitation reduction, so owing to do not exist top value field voltage not need to carry out this calculation of parameter.

4. the excitation system adjusting function in-service monitoring analytical approach based on phasor measuring technique according to claim 3 is characterized in that: in described step 22) in, calculate for voltage regulation accuracy before the disturbance: calculation interval T _sFor t constantly takes place in this disturbance ₁Preceding T _sSecond, if time interval T constantly takes place to this disturbance the finish time in last disturbance _Diff＜T _s, T then _sBe taken as T _DiffCalculate for voltage regulation accuracy after the disturbance: calculation interval T _sBe this disturbance t finish time ₂Back T _sSecond, if time interval T constantly takes place to disturbance next time the finish time in this disturbance _Diff＜T _s, T then _sBe taken as T _Diff

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