CN102087316B - Online monitoring method for short-circuit impedance of V/X connection traction transformer - Google Patents

Abstract

The invention discloses an online monitoring method for the short-circuit impedance of a V/X connection traction transformer. In two time intervals when the negative feeder line current of a power supply arm is 90-95% of the rated current and 95-100% of the rated current, the method tests and records a voltage vector and a current vector of the incoming line side and the feeder line side of the transformer respectively, calculates to obtain a primary test value of the short-circuit impedance by use of a deduced formula, and repeatedly tests and calculates for n times (n is not less than 20) to obtain two groups of primary test data; for each group of data, the method judges the relative standard deviation of the primary test data to eliminate the data with large error; and if the number of the eliminated data is less than n/4, the average of the remaining data is the value of the tested short-circuit impedance. The method is simple to test and has high accuracy; and the curve of the monitored short-circuit impedance changing with time can be used as the basis for monitoring and judging the winding deformation.

Description

A kind of method of V/X Connection Traction Transformer short-circuit reactance on-line monitoring

Technical field

The present invention relates to the on-line monitoring technique of electric railway high voltage electric equipment, refer more particularly to V/X Connection Traction Transformer short-circuit reactance on-line monitoring technique, belong to status of electric power detection technique field.

Background technology

The Chinese Railway construction has welcome beyond example great development; The high speed passenger dedicated railway Large scale construction; Its total kilometrage has been broken through 7000 kilometers, military wide (Wuhan--Guangzhou), the highest running speed of Line for Passenger Transportation EMUs such as Shanghai and Nanjing (Shanghai--Nanjing) has surpassed 350km/h, on February 19th, 2010; The china railway odd-numbered day volume of the flow of passengers records high, and reaches 6,330,000 person-times; The coal of heavy duty fortune simultaneously special line improves constantly annual traffic, intends to break through in 2010 the high point of 400,000,000 tons of annual traffics like Qun Dynasty's railway; The great development of high speed and heavy haul railway is to promoting China's economy and social development significant.It is thus clear that owing to the traction power supply equipment failure causes transporting the negative effect that interruption possibly bring also is huge.Tractive transformer is the most expensive, most important traction power supply equipment; In high speed and part heavy haul railway; Extensively adopt the transformer of the V/X mode of connection at present, the transformer of this structure is used for the AT power supply mode can save the autotransformer in the traction substation, has not only saved equipment cost; Reduce floor area, eliminated in the traction substation AT autotransformer higher hidden danger of probability that breaks down simultaneously.The same with the tractive transformer of other types; The winding deformation test is an important content of the test; Its method mainly comprises Low Voltage Impulse Method, hunting of frequency method and short-circuit reactance method etc.; Because the singularity of V/X wiring transformer winding connection mode, the on-line monitoring method that is used for other deformations of transformer winding is also inapplicable to it, and therefore the present detection method that adopts all is the off-line test method.

Could detect after adopting off-line method test V/X Connection Traction Transformer winding deformation to have a power failure; And need untie the original wiring of winding, the workload of test is very big, can not reflect the situation of winding deformation in addition in real time; And invented can be used for the winding deformation on-line monitoring in V/X Connection Traction Transformer short-circuit impedance technology; Overcome the last shortcoming of off-line test, had in real time, monitoring function automatically, for the transformer state maintenance provides the basis.

Summary of the invention

Situation to prior art; The present invention provides a kind of method of V/X Connection Traction Transformer short-circuit reactance on-line monitoring; Adopt this method; Can in real time, automatically monitor the short-circuit reactance of V/X transformer, and then help to judge the winding deformation state, can carry out the basic data that repair based on condition of component provides the winding deformation aspect for the tractive transformer of V/X wiring.

The present invention solves the problems of the technologies described above the technical scheme that is adopted and comprises the steps:

The first step: at a supply arm negative feeder electric current is 0.9 to 0.95 times of rated current and two periods of 0.95 to 1.0 times of rated current; Respectively with waveform greater than each 10 power frequency period of voltage and current of the positive feeder of the voltage and current of each phase of 4000 times/second SF record transformer high-voltage side, a supply arm and negative feeder; In view of the above, try to achieve the line voltage vector of two period high-pressure side A, B two between mutually

A phase current vector

The positive feeder voltage vector The positive feeder current vector

The negative feeder voltage vector

The negative feeder current vector Intend from the high-pressure side short-circuit reactance (x of A, the test of B end through computes _KAB) preliminary test value,

$x_{\mathrm{kAB}}=\left\{\right[\mathrm{Re}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}\right)\mathrm{Re}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}\right)-\mathrm{Im}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}\right)\mathrm{Im}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}\right)$

$-\mathrm{Re}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}\right)\mathrm{Re}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}\right)+\mathrm{Im}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}\right)\mathrm{Im}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}\right)]\mathrm{Re}(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})$

$-[\mathrm{Im}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}\right)\mathrm{Re}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}\right)+\mathrm{Re}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}\right)\mathrm{Im}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}\right)-$

$\mathrm{Im}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}\right)\mathrm{Re}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}\right)+\mathrm{Re}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}\right)\mathrm{Im}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}\right)\left]\mathrm{Im}(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})\right\}/$

$[\mathrm{Re}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})}^2+\mathrm{Im}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})}^2]+K\{\mathrm{Im}(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})$

$\×\mathrm{Re}(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})-\mathrm{Re}(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})\mathrm{Im}(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})\}/$

$[\mathrm{Re}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})}^2+\mathrm{Im}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})}^2]+K\{\mathrm{Im}(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(1\right)}+K{{\stackrel{\·}{U}}_{\mathrm{Fa}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(2\right)}+K{{\stackrel{\·}{U}}_{\mathrm{Fa}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})$

$\×\mathrm{Re}(\frac{{{\stackrel{\·}{I}}_{\mathrm{Fa}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{Fa}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}})-\mathrm{Re}(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(1\right)}+K{{\stackrel{\·}{U}}_{\mathrm{Fa}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(2\right)}+K{{\stackrel{\·}{U}}_{\mathrm{Fa}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})\mathrm{Im}(\frac{{{\stackrel{\·}{I}}_{\mathrm{Fa}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{Fa}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}})\}/$

$[\mathrm{Re}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{Fa}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{Fa}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}})}^2+\mathrm{Im}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{Fa}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{Fa}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}})}^2]$

Second step: at β supply arm negative feeder electric current is 0.9 to 0.95 times of rated current and two periods of 0.95 to 1.0 times of rated current; Respectively with waveform greater than each 10 power frequency period of voltage and current of the positive feeder of the voltage and current of each phase of 4000 times/second SF record transformer high-voltage side, β supply arm and negative feeder; In view of the above, try to achieve the line voltage vector of two period high-pressure side C, B two between mutually C phase current vector

The positive feeder voltage vector

The positive feeder current vector The negative feeder voltage vector

The negative feeder current vector

Intend from the high-pressure side short-circuit reactance (x of C, the test of B end through computes _KCB) preliminary test value,

$x_{\mathrm{kCB}}=\left\{\right[\mathrm{Re}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}\right)\mathrm{Re}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}\right)-\mathrm{Im}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}\right)\mathrm{Im}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}\right)$

$-\mathrm{Re}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}\right)\mathrm{Re}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}\right)+\mathrm{Im}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}\right)\mathrm{Im}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}\right)]\mathrm{Re}(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})$

$-[\mathrm{Im}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}\right)\mathrm{Re}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}\right)+\mathrm{Re}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}\right)\mathrm{Im}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}\right)-$

$\mathrm{Im}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}\right)\mathrm{Re}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}\right)+\mathrm{Re}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}\right)\mathrm{Im}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}\right)\left]\mathrm{Im}(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{CB}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})\right\}/$

$[\mathrm{Re}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})}^2+\mathrm{Im}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})}^2]+K\{\mathrm{Im}(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})$

$\×\mathrm{Re}(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})-\mathrm{Re}(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})\mathrm{Im}(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})\}/$

$[\mathrm{Re}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})}^2+\mathrm{Im}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})}^2]+K\{\mathrm{Im}(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(1\right)}+K{{\stackrel{\·}{U}}_{\mathrm{F\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(2\right)}+K{{\stackrel{\·}{U}}_{\mathrm{F\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})$

$\×\mathrm{Re}(\frac{{{\stackrel{\·}{I}}_{\mathrm{F\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{F\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}})-\mathrm{Re}(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(1\right)}+K{{\stackrel{\·}{U}}_{\mathrm{F\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(2\right)}+K{{\stackrel{\·}{U}}_{\mathrm{F\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})\mathrm{Im}(\frac{{{\stackrel{\·}{I}}_{\mathrm{F\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{F\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}})\}/$

$[\mathrm{Re}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{F\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{F\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}})}^2+\mathrm{Im}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{F\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{F\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}})}^2]$

The 3rd step: n (n is not less than 20) is inferior altogether to repeat first, second step, obtains two groups of preliminary test datas, to every group of data; Reject the bigger number of error according to its relative standard deviation respectively, promptly when relative standard deviation more than or equal to 0.2% the time, remove number with the mean value disparity; Constantly remove the maximum number of error according to this method, till relative standard deviation is less than 0.2%, if the amount of removing data is less than n/4; Then the mean value of remaining data is the short-circuit impedance value of this monitoring; Otherwise, think because test error is bigger, abandon this monitoring.

The principle that the present invention relates to is following:

The connection synoptic diagram of the tractive transformer winding of V/X wiring is as shown in Figure 1.High side phase current

and the feeder current

the relationship formula 1.

${\left[\begin{array}{ccc}{\stackrel{\·}{I}}_A& {\stackrel{\·}{I}}_B& {\stackrel{\·}{I}}_C\end{array}\right]}^T=\frac{1}{K}\left[\begin{array}{cccc}1& 1& 0& 0\\ -1& -1& -1& -1\\ 0& 0& 1& 1\end{array}\right]{\left[\begin{array}{cccc}{\stackrel{\·}{I}}_{\mathrm{Ta}}& {\stackrel{\·}{I}}_{\mathrm{Fa}}& {\stackrel{\·}{I}}_{\mathrm{T\β}}& {\stackrel{\·}{I}}_{\mathrm{F\β}}\end{array}\right]}^T---\left(1\right)$

In the formula (1), K is a scale-up factor, provides when transformer dispatches from the factory, and also can record through instrumentation.

The equivalent electrical circuit of V/X Connection Traction Transformer is shown in accompanying drawing 2.According to equivalent electrical circuit, satisfy the relation of formula (2) and formula (3) at any time.

${\stackrel{\·}{U}}_{\mathrm{AB}}=(r_A+j{x}_A){\stackrel{\·}{I}}_A+K(r_{\mathrm{Ta}}+j{x}_{\mathrm{Ta}}){\stackrel{\·}{I}}_{\mathrm{Ta}}+K{\stackrel{\·}{U}}_{\mathrm{Ta}}$ (2)

$=(r_A+j{x}_A){\stackrel{\·}{I}}_A-K(r_{\mathrm{Fa}}+j{x}_{\mathrm{Fa}}){\stackrel{\·}{I}}_{\mathrm{Fa}}-K{\stackrel{\·}{U}}_{\mathrm{Fa}}$

${\stackrel{\·}{U}}_{\mathrm{CB}}=(r_C+j{x}_C){\stackrel{\·}{I}}_C+K(r_{\mathrm{T\β}}+j{x}_{\mathrm{T\β}}){\stackrel{\·}{I}}_{\mathrm{T\β}}+K{\stackrel{\·}{U}}_{\mathrm{T\β}}$ (3)

$=(r_C+j{x}_C){\stackrel{\·}{I}}_C-K(r_{\mathrm{T\β}}+j{x}_{\mathrm{T\β}}){\stackrel{\·}{I}}_{\mathrm{F\β}}-K{\stackrel{\·}{U}}_{\mathrm{F\β}}$

For obtaining the reactance value in formula (2) and the formula (3), need obtain two groups of independently voltage and current vectors.In order to obtain intending from the high-pressure side short-circuit reactance (x of A, the test of B end _KAB), can be two periods, voltage and current, the positive feeder of a supply arm and the some power frequency periods of voltage and current of negative feeder of each phase of SF record transformer high-voltage side are tried to achieve the line voltage vector between two period high-pressure side A, B two phases respectively

A phase current vector

The positive feeder voltage vector

The positive feeder current vector

The negative feeder voltage vector

The negative feeder current vector

Be the influence of harmonic carcellation to sampling, SF is more than or equal to 2 times of 40 subfrequencies, promptly greater than 4000 times/second; Simultaneously in order to reduce error; Each sampling period is decided to be 10 power frequency periods, and promptly 0.2 second, in order to reduce the short-circuit reactance monitoring and the error of calculation that load variations causes; Do reference with the load current of a supply arm in definite sampling time during section, when a supply arm negative feeder electric current is 0.9 to 0.95 times of rated current and 0.95 to 1.0 times of rated load, gather respectively.The vector of two groups of voltage and currents difference substitution formula (2), try to achieve:

In the formula, the imaginary part of the plural X of Im (X) representative, the real part of the plural X of Re (X) representative.

When step down side T terminals and F terminals short circuit, the short-circuit impedance that the test of A and B end obtains from the high-pressure side is:

x _kAB＝x _A+K ²(x _Ta+x _Fa) (5)

Therefore find the solution formula (4), obtain short-circuit impedance x _KABFor:

$x_{\mathrm{kAB}}=\left\{\right[\mathrm{Re}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}\right)\mathrm{Re}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}\right)-\mathrm{Im}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}\right)\mathrm{Im}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}\right)$

$-\mathrm{Re}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}\right)\mathrm{Re}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}\right)+\mathrm{Im}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}\right)\mathrm{Im}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}\right)]\mathrm{Re}(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})$

$-[\mathrm{Im}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}\right)\mathrm{Re}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}\right)+\mathrm{Re}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}\right)\mathrm{Im}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}\right)-$

$\mathrm{Im}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}\right)\mathrm{Re}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}\right)+\mathrm{Re}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}\right)\mathrm{Im}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}\right)\left]\mathrm{Im}(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})\right\}/$

$[\mathrm{Re}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})}^2+\mathrm{Im}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})}^2]+K\{\mathrm{Im}(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})$

$\×\mathrm{Re}(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})-\mathrm{Re}(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})\mathrm{Im}(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})\}/$

$[\mathrm{Re}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})}^2+\mathrm{Im}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{Ta}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})}^2]+K\{\mathrm{Im}(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(1\right)}+K{{\stackrel{\·}{U}}_{\mathrm{Fa}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(2\right)}+K{{\stackrel{\·}{U}}_{\mathrm{Fa}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})$

$\×\mathrm{Re}(\frac{{{\stackrel{\·}{I}}_{\mathrm{Fa}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{Fa}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}})-\mathrm{Re}(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(1\right)}+K{{\stackrel{\·}{U}}_{\mathrm{Fa}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(2\right)}+K{{\stackrel{\·}{U}}_{\mathrm{Fa}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})\mathrm{Im}(\frac{{{\stackrel{\·}{I}}_{\mathrm{Fa}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{Fa}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}})\}/---\left(6\right)$

$[\mathrm{Re}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{Fa}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{Fa}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}})}^2+\mathrm{Im}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{Fa}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{Fa}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}})}^2]$

In order to obtain intending from the high-pressure side short-circuit reactance (x of C, the test of B end _KCB), can be in two other period, the voltage and current of each phase of record transformer high-voltage side, the positive feeder of β supply arm and each several power frequency period of voltage and current of negative feeder are tried to achieve the line voltage vector between two stage high-pressure side C, B two phases

C phase current vector

The positive feeder voltage vector

The positive feeder current vector

The negative feeder voltage vector

The negative feeder current vector

Be similarly the influence of harmonic carcellation to sampling, SF is more than or equal to 2 times of 40 subfrequencies, promptly greater than 4000 times/second; In order to reduce error; Each sampling period is decided to be 10 power frequency periods, and promptly 0.2 second, in order to reduce the short-circuit reactance monitoring and the error of calculation that load variations causes; Do reference with the load current of β supply arm in definite sampling time during section, when β supply arm negative feeder electric current is 0.9 to 0.95 times of rated current and 0.95 to 1.0 times of rated load, gather respectively.The vector of two groups of voltage and currents difference substitution formula (3), try to achieve:

In the formula, the imaginary part of the plural X of Im (X) representative, the real part of the plural X of Re (X) representative.

When step down side T terminals and F terminals short circuit, the short-circuit impedance that the test of C and B end obtains from the high-pressure side is:

x _kCB＝x _C+K ²(x _Tβ+x _Fβ) (8)

Therefore, find the solution formula (7), try to achieve short-circuit reactance x _KCBFor:

$x_{\mathrm{kCB}}=\left\{\right[\mathrm{Re}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}\right)\mathrm{Re}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}\right)-\mathrm{Im}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}\right)\mathrm{Im}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}\right)$

$-\mathrm{Re}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}\right)\mathrm{Re}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}\right)+\mathrm{Im}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}\right)\mathrm{Im}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}\right)]\mathrm{Re}(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})$

$-[\mathrm{Im}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}\right)\mathrm{Re}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}\right)+\mathrm{Re}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}\right)\mathrm{Im}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}\right)-$

$\mathrm{Im}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}\right)\mathrm{Re}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}\right)+\mathrm{Re}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}\right)\mathrm{Im}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}\right)\left]\mathrm{Im}(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{CB}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})\right\}/$

$[\mathrm{Re}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})}^2+\mathrm{Im}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})}^2]+K\{\mathrm{Im}(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})$

$\×\mathrm{Re}(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})-\mathrm{Re}(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})\mathrm{Im}(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})\}/---\left(9\right)$

$[\mathrm{Re}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})}^2+\mathrm{Im}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})}^2]+K\{\mathrm{Im}(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(1\right)}+K{{\stackrel{\·}{U}}_{\mathrm{F\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(2\right)}+K{{\stackrel{\·}{U}}_{\mathrm{F\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})$

$\×\mathrm{Re}(\frac{{{\stackrel{\·}{I}}_{\mathrm{F\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{F\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}})-\mathrm{Re}(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(1\right)}+K{{\stackrel{\·}{U}}_{\mathrm{F\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(2\right)}+K{{\stackrel{\·}{U}}_{\mathrm{F\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})\mathrm{Im}(\frac{{{\stackrel{\·}{I}}_{\mathrm{F\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{F\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}})\}/$

$[\mathrm{Re}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{F\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{F\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}})}^2+\mathrm{Im}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{F\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{F\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}})}^2]$

Since in the on-line monitoring process, test the interference that resulting data possibly receive many-sided factor, effective in order to make test data; Follow-on test n (n is not less than 20) is inferior, obtains two groups of preliminary test datas, to every group of data; Reject the bigger number of error according to its relative standard deviation respectively, promptly when relative standard deviation more than or equal to 0.2% the time, remove number with the mean value disparity; Constantly remove the maximum number of error according to this method, till relative standard deviation is less than 0.2%, if the amount of removing data is less than n/4; Then the mean value of remaining data is the short-circuit impedance value of this monitoring; Otherwise, think because test error is bigger, abandon this monitoring.Idiographic flow is seen Fig. 3.

Description of drawings

Fig. 1 is the connection synoptic diagram of winding of the tractive transformer of V/X wiring;

Fig. 2 is the equivalent circuit diagram of the tractive transformer of V/X wiring;

Fig. 3 is short-circuit reactance test value flow chart of data processing figure.

Embodiment

Below in conjunction with accompanying drawing and embodiment, the present invention is done further detailed description.

Embodiment

Short-circuit impedance to certain traction substation 1# main transformer (mode of connection is the V/X wiring) is monitored; Its high-pressure side, low-pressure side rated voltage are respectively 110kV, 27.5kV; Capacity is 15MVA+16.5MVA; The short-circuit impedance of A, the test of B end is 67.60 Ω when dispatching from the factory, and the short-circuit impedance of C and the test of B end is 61.53 Ω, and the back of putting into operation is respectively 67.40 Ω and 61.27 Ω with accurate inductance analyser test short-circuit reactance.

According to the requirement of this on-line monitoring, need the phase voltage and the electric current of test transformer inlet wire, and the voltage-to-ground of all feeder lines and electric current; Therefore must the voltage transformer (VT) summation current transformer be installed in the relevant position, generally speaking, according to the requirement of metering and relay protection; These mutual inductors have been installed in the electric substation; In this instance, the simulating signal of electric current and voltage is all obtained from measuring screen and relay-set, through after step-down, the filtering by multi pass acquisition card image data.Accomplish the monitoring of one whole ground according to following steps:

The first step: at a supply arm negative feeder electric current is 275A and two periods of 290A; Write down the voltage and current of each phase of transformer high-voltage side, the positive feeder of a supply arm and each 10 power frequency period of voltage and current of negative feeder with 4096 times/second SF respectively, try to achieve the line voltage vector between two period high-pressure side A, B two phases A phase current vector

The positive feeder voltage vector

The positive feeder current vector

The negative feeder voltage vector

The negative feeder current vector

Through type (6) calculates the short-circuit reactance of intending from the high-pressure side A, the test of B end, obtains x _KAB=67.26 Ω;

Second step: at β supply arm negative feeder electric current is 300A and two periods of 320A; Write down the voltage and current of each phase of transformer high-voltage side, the positive feeder of β supply arm and each 10 power frequency period of voltage and current of negative feeder with 4096 times/second SF respectively, try to achieve the line voltage vector between two period high-pressure side C, B two phases

C phase current vector

The positive feeder voltage vector

The positive feeder current vector

The negative feeder voltage vector

The negative feeder current vector

Through type (6) calculates the short-circuit reactance x that intends from the high-pressure side C, the test of B end _KCB=61.15 Ω;

The 3rd step: repeat first, second and go on foot totally 20 times; Obtain two groups of preliminary test datas; First group is 67.44,67.15,67.30,67.26,67.42,67.37,67.24,67.07,67.39,67.24,67.31,68.20,67.43,67.36,67.13,68.00,67.44,67.43,67.23,67.42; Second group of number is 61.15,61.30,61.27,61.20,61.2,61.21,62.25,61.07,61.09,61.16,61.23,61.08,58.15,61.17,61.10,61.22,61.17,61.13,61.22,61.19, carries out data processing according to the flow process of Fig. 3 respectively below; To first group of number, the relative standard deviation of trying to achieve 20 numbers is 0.42%, greater than 0.2%; Therefore remove and maximum several 68.2 of equal value differences, the relative standard deviation of trying to achieve remaining 19 numbers is 0.3%, greater than 0.2%; Therefore remove from several 68.0 of equal value difference maximum; The relative standard deviation of trying to achieve remaining 18 numbers is 0.16%, less than 0.2%, so short-circuit reactance x _KABBe 67.31 Ω, handle second group of number equally, obtain short-circuit reactance x _KCBBe 61.18 Ω.

In sum, this monitoring is respectively 67.31 Ω and 61.18 Ω from the short-circuit impedance that A, B and C, the test of B end obtain, and is very identical with the off-line test result.

Claims (1)

1. the method for a V/X Connection Traction Transformer short-circuit reactance on-line monitoring is characterized in that testing according to following steps:

The first step: at α supply arm negative feeder electric current is 0.9 to 0.95 times of rated current and two periods of 0.95 to 1.0 times of rated current; Respectively with waveform greater than each 10 power frequency period of voltage and current of the positive feeder of the voltage and current of each phase of 4000 times/second SF record transformer high-voltage side, α supply arm and negative feeder; In view of the above, try to achieve the line voltage vector of two period high-pressure side A, B two between mutually

A phase current vector

The positive feeder voltage vector

The positive feeder current vector

The negative feeder voltage vector

The negative feeder current vector

Intend from the high-pressure side short-circuit reactance (x of A, the test of B end through computes _KAB) preliminary test value,

$x_{\mathrm{kAB}}=\left\{\right[\mathrm{Re}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(2\right)}-{K{\stackrel{\·}{U}}_{\mathrm{T\α}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}\right)\mathrm{Re}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\α}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}\right)-\mathrm{Im}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\α}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}\right)\mathrm{Im}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\α}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}\right)$

$-\mathrm{Re}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(1\right)}-{K{\stackrel{\·}{U}}_{\mathrm{T\α}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}\right)\mathrm{Re}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\α}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}\right)+\mathrm{Im}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\α}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}\right)\mathrm{Im}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\α}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}\right)]\mathrm{Re}(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\α}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\α}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})$

$-[\mathrm{Im}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(2\right)}-{K{\stackrel{\·}{U}}_{\mathrm{T\α}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}\right)\mathrm{Re}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\α}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}\right)+\mathrm{Re}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\α}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}\right)\mathrm{Im}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\α}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}\right)-$

$\mathrm{Im}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(1\right)}-{K{\stackrel{\·}{U}}_{\mathrm{T\α}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}\right)\mathrm{Re}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\α}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}\right)+\mathrm{Re}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\α}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}\right)\mathrm{Im}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\α}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}\right)\left]\mathrm{Im}(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\α}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\α}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})\right\}/$

$[\mathrm{Re}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\α}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\α}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})}^2+\mathrm{Im}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\α}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\α}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})}^2]+K\{\mathrm{Im}(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\α}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\α}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})$

$\×\mathrm{Re}(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\α}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\α}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})-\mathrm{Re}(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\α}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\α}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})\mathrm{Im}(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\α}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\α}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})\}/$

$[\mathrm{Re}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\α}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\α}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})}^2+\mathrm{Im}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\α}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\α}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})}^2]+K\{\mathrm{Im}(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(1\right)}+K{{\stackrel{\·}{U}}_{\mathrm{F\α}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(2\right)}+K{{\stackrel{\·}{U}}_{\mathrm{F\α}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})$

$\×\mathrm{Re}(\frac{{{\stackrel{\·}{I}}_{\mathrm{F\α}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{F\α}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}})-\mathrm{Re}(\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(1\right)}+K{{\stackrel{\·}{U}}_{\mathrm{F\α}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}}-\frac{{\stackrel{\·}{U}}_{\mathrm{AB}}^{\left(2\right)}+K{{\stackrel{\·}{U}}_{\mathrm{F\α}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}})\mathrm{Im}(\frac{{{\stackrel{\·}{I}}_{\mathrm{F\α}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{F\α}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}})\}/$

$[\mathrm{Re}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{F\α}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{F\α}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}})}^2+\mathrm{Im}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{F\α}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_A}^{\left(2\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{F\α}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_A}^{\left(1\right)}})}^2]$

In the formula, K is a scale-up factor, and the V/X Connection Traction Transformer provides when dispatching from the factory, and also available instrument records.

Second step: at β supply arm negative feeder electric current is 0.9 to 0.95 times of rated current and two periods of 0.95 to 1.0 times of rated current; Respectively with waveform greater than each 10 power frequency period of voltage and current of the positive feeder of the voltage and current of each phase of 4000 times/second SF record transformer high-voltage side, β supply arm and negative feeder; In view of the above, try to achieve the line voltage vector of two period high-pressure side C, B two between mutually

C phase current vector

The positive feeder voltage vector

The positive feeder current vector

The negative feeder voltage vector

The negative feeder current vector Intend from the high-pressure side short-circuit reactance (x of C, the test of B end through computes _KCB) preliminary test value,

$x_{\mathrm{kCB}}=\left\{\right[\mathrm{Re}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(2\right)}-{K{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}\right)\mathrm{Re}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}\right)-\mathrm{Im}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}\right)\mathrm{Im}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}\right)$

$-\mathrm{Re}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(1\right)}-{K{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}\right)\mathrm{Re}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}\right)+\mathrm{Im}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}\right)\mathrm{Im}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}\right)]\mathrm{Re}(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})$

$-[\mathrm{Im}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(2\right)}-{K{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}\right)\mathrm{Re}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}\right)+\mathrm{Re}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}\right)\mathrm{Im}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}\right)-$

$\mathrm{Im}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(1\right)}-{K{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}\right)\mathrm{Re}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}\right)+\mathrm{Re}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}\right)\mathrm{Im}\left(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}\right)\left]\mathrm{Im}(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{C\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})\right\}/$

$[\mathrm{Re}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})}^2+\mathrm{Im}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})}^2]+K\{\mathrm{Im}(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})$

$\×\mathrm{Re}(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})-\mathrm{Re}(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(1\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(2\right)}-K{{\stackrel{\·}{U}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})\mathrm{Im}(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})\}/$

$[\mathrm{Re}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})}^2+\mathrm{Im}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{T\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})}^2]+K\{\mathrm{Im}(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(1\right)}+K{{\stackrel{\·}{U}}_{\mathrm{F\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(2\right)}+K{{\stackrel{\·}{U}}_{\mathrm{F\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})$

$\×\mathrm{Re}(\frac{{{\stackrel{\·}{I}}_{\mathrm{F\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{F\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}})-\mathrm{Re}(\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(1\right)}+K{{\stackrel{\·}{U}}_{\mathrm{F\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}}-\frac{{\stackrel{\·}{U}}_{\mathrm{CB}}^{\left(2\right)}+K{{\stackrel{\·}{U}}_{\mathrm{F\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}})\mathrm{Im}(\frac{{{\stackrel{\·}{I}}_{\mathrm{F\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{F\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}})\}/$

$[\mathrm{Re}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{F\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{F\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}})}^2+\mathrm{Im}{(\frac{{{\stackrel{\·}{I}}_{\mathrm{F\β}}}^{\left(2\right)}}{{{\stackrel{\·}{I}}_C}^{\left(2\right)}}-\frac{{{\stackrel{\·}{I}}_{\mathrm{F\β}}}^{\left(1\right)}}{{{\stackrel{\·}{I}}_C}^{\left(1\right)}})}^2]$

In the formula, the value of K is identical with the first step.

The 3rd step: repeat first, second and go on foot n time altogether, n is not less than 20, obtains two groups of preliminary test datas; To every group of data, reject the bigger number of error according to its relative standard deviation respectively, promptly when relative standard deviation more than or equal to 0.2% the time; Remove the number with the biggest gap, constantly remove the maximum number of error according to this method, till relative standard deviation is less than 0.2% with mean value; If the amount of removing data is less than n/4, then the mean value of remaining data is the short-circuit impedance value of this monitoring, otherwise; Think because test error is bigger, abandon this monitoring.

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