CN1760686A - Method for checking out phase handling unit (PHU) in site - Google Patents

Abstract

The method is in use for checkout on site by using synchronous phase measuring unit (PMU). Arrangement and steps of the method are as following: one PMU tester and one PC with communication software for simulating main station are utilized; PMU device to be measured and PMU tester are connected to same AC signal source; PMU device and PMU tester receive own GPS satellite clock synchronization signal respectively; through data LAN, PC receives data of real phase of PMU device and PMU tester; time synchronism sorting is carried out according to GPS timing mark carried by own data message for data of real phase from PMU device and PMU tester; then, error comparison and root-mean-square error calculation are carried out for two sets of data at same time within a period of time; finally, root-mean-square error and confidence interval of error are obtained.

Description

Phasor measuring set (PMU) on-site calibrating method

Technical field

The invention discloses a kind of method that phasor measuring set (PMU) carries out field-checking that is used for, this method adopts the error analysis of the canonical measure data sync contrast of the measurement data of tested PMU and PMU tester.The present invention is mainly used in the engineering construction of WAMS (WAMS), belongs to the Power System and its Automation field.

Background technology

Move in order to ensure area electric network safety stabilization, each big electrical network has been accelerated the application of WAMS (WAMS) and phasor measuring set (PMU) both at home and abroad, in some load-center substations and big power station the PMU device be installed carried out synchronous phasor measurement, transmit dynamic phasor information to the WAMS main station system, the WAMS main website implements the dynamic stability monitoring according to the metrical information of PMU to electrical network.In practical engineering application, for make on-the-spot PMU can guarantee to require situation under move, must test every performance index of PMU, verification.And present method of calibration generally is confined under the reasonable laboratory condition.

The field-checking of PMU device, comprise the verification (under the precision checking under the rated frequency under precision checking, the frequency conversion rate, the harmonic condition under precision checking, the three-phase imbalance state under precision checking, the power factor change condition precision checking) of real time data precision, the real time record test, parts such as the verifying correctness of communication performance test (Frame uploading speed, message equispaced, frame head error rate, frame length error rate, CRC check error rate detect), communication protocol, gps clock precision checking.

The PMU device adopts the sampling rate of 4800-10000 point/second that electric current, voltage are sampled, and is transmitted by per second 25-100 frame rate by the dynamic phasor data that quick Fourier transformation (FFT) algorithm obtains.The phasor data of electrical network change fast along with the variation of time, and traditional calibration equipment or AC sampling transmitter etc. can not provide dynamic phasor data, and the amplitude data of electrical network stable state can only be provided.For a long time, its amplitude precision is only checked in a large amount of PMU field performance tests, other indexs can only be carried out under reasonable laboratory condition, especially to critical satellite time synchronization accuracy wherein, unit built-in potential merit angle and circuit phasor, communication protocol and transmission performance etc. lack direct means of testing, general by behind the systems connection, check the correctness of phase angle measurement roughly by main website, so can only be qualitative to it, can not carry out quantitative error analysis, a large amount of electrical network dynamic datas that the PMU that is distributed in different factories station is gathered, be difficult to determine measuring accuracy and differentiate overproof data, have a strong impact on technological assessment according to technical standard, final acceptance of construction and operation maintenance.

Summary of the invention

For solving the problem of aforementioned existence, the invention provides a kind of method of synchronous phasor measuring device (PMU) being carried out field-checking, this method adopts the method for measured data and the comparison of canonical measure data sync that on-the-spot PMU is carried out on-line testing, this method comprises the PC of a PMU tester and a simulation main website, and the checking procedure of this method is:

1) scene is imported the voltage signal of tested PMU device and connect into, current signal series connection inserts the PMU tester, makes PMU tester and tested PMU device obtain homology alternating voltage and current signal:

2) tested PMU device and PMU tester receive gps satellite clock sync signal separately respectively, make the measuring error of synchronized phasor comprise gps satellite clock and synchronous error separately;

3) be loaded with the PC of simulating master station communication software, receive the real-time phasor data of tested PMU device and PMU tester by data lan simultaneously;

4) to real-time phasor data from tested PMU device and PMU tester, carry out the time synchronized ordering by the GPS markers that data message separately carries, again two groups of data in each identical moment in a period of time are carried out error ratio, root-mean-square error is calculated;

5) adopt the normally distributed error statistic law, analyze the data error of tested PMU device, provide root-mean-square error and error fiducial interval.

6) detect the communication message of tested PMU device and the accordance of transmission course and standard traffic stipulations by the PC that loads simulation master station communication software, also can test and analyze the stationarity of communication flows, the error rate of data hardwood, the correct responsiveness of order pipeline etc.

Description of drawings

Accompanying drawing is a message exchange synoptic diagram between tested PMU device of the present invention, PMU tester and the PC of simulating main website.

Embodiment

Accompanying drawing has disclosed message exchange synoptic diagram between the PC of tested PMU device of the present invention, PMU tester and simulation main website; The PC of simulation master station communication software is housed, receives the real-time phasor data of tested PMU device and PMU tester by data lan simultaneously; Carry out the time synchronized ordering by the GPS markers that data message separately carries,, carry out error ratio, root-mean-square error is calculated again to two groups of data of thousands of point samplings in each identical moment in a period of time.

Error analysis adopts absolute error maximal value, root-mean-square error, stochastic error to distribute:

Absolute error maximal value: err _Max=MAX (| x _i-x _i|)

Root-mean-square error:

${\mathrm{err}}_{\mathrm{sqrt}}=\sqrt{\frac{\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{(x_i-{\stackrel{\‾}{x}}_i)}^2}{N}}$

Stochastic error distributes:

(1) probability density function of normal distribution: $f\left(x\right)=\frac{1}{\sqrt{2\mathrm{\π}}}{e}^{-\frac{{(x-\stackrel{\‾}{x})}^2}{{2\mathrm{\σ}}^2}}.$

(2) standardized normal distribution calculates: $\mathrm{\φ}\left(u\right)=\frac{1}{\sqrt{2\mathrm{\π}}}\underset{-\∞}{\overset{u}{\∫}}{e}^{-\frac{x^2}{2}}\mathrm{dx}(u\≥0).$

(3) wherein $\mathrm{\σ}=\sqrt{\frac{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{(x_i-\stackrel{\‾}{x})}^2}{n-1}},$ Wherein $\stackrel{\‾}{x}=\frac{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{x}_i}{n}.$ X is an error amount.

(4) according to measurement data, obtain error amount, according to given degree of confidence, look into gaussian distribution table or according to probability density function evaluation integration, error of calculation interval.Table look-up and the numerical integration value be made as δ.

(5) get fiducial interval and be [x-δ * σ, x+ δ * σ].

Claims (1)

1, a kind of phasor measuring set PMU on-site calibrating method comprises a PMU tester and a PC of simulating main website, and it is characterized in that: the checking procedure of this method is:

1) scene is imported the voltage signal of tested PMU device and connect into, current signal series connection PMU tester, make PMU tester and tested PMU device obtain homology alternating voltage and current signal;

2) tested PMU device and PMU tester receive gps satellite clock sync signal separately respectively, make the measuring error of synchronized phasor comprise gps satellite clock and synchronous error separately;

3) be loaded with the PC of simulating master station communication software, receive the real-time phasor data of tested PMU device and PMU tester by data lan simultaneously;

4) to real-time phasor data from tested PMU device and PMU tester, carry out the time synchronized ordering by the GPS markers that data message separately carries, again two groups of data in each identical moment in a period of time are carried out error ratio, root-mean-square error is calculated;

5) adopt the normally distributed error statistic law, analyze the data error of tested PMU device, provide root-mean-square error and error fiducial interval.