CN102435858A - Method and system for online measurement of short-circuit loss and open-circuit loss of transformer - Google Patents

Method and system for online measurement of short-circuit loss and open-circuit loss of transformer Download PDF

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CN102435858A
CN102435858A CN2011102734167A CN201110273416A CN102435858A CN 102435858 A CN102435858 A CN 102435858A CN 2011102734167 A CN2011102734167 A CN 2011102734167A CN 201110273416 A CN201110273416 A CN 201110273416A CN 102435858 A CN102435858 A CN 102435858A
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transformer
short
voltage
circuit
loss
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陈民铀
何为
李霞
叶君
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Chongqing University
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Chongqing University
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Abstract

The invention belongs to the technical field of a power system, and particularly discloses a method for online measurement of short-circuit loss and open-circuit loss of a transformer. The method is based on the measurement principle that firstly short-circuit impedance of the transformer is calculated by utilizing the voltage and the current of the primary side and secondary side of the transformer, and then the short-circuit loss and open-circuit loss is calculated by utilizing the short-circuit impedance. According the property that the primary side voltage during normal operation of the transformer almost does not change with loads, an ideal AC constant-voltage source is used to substitute the primary side voltage of the transformer. Then a data collection device is adopted to collect a primary side current signal and secondary side voltage and current signals of the transformer; and the collected voltage and current signals as well as the constant-voltage source signals are processed by certain numerical calculation, and linear fitting is used to achieve the online short-circuit impedance measurement. Finally, the short-circuit loss and open-circuit loss of the transformer are calculated by utilizing the measured short-circuit impedance. The measurement method can save a great amount of manpower and material resources, and does not affect the continuity of power supply.

Description

Transformer short-circuit is lost and open circuit is lost On-line Measuring Method and system
Technical field
The present invention relates to technical field of power systems, and in particular to a kind of On-line Measuring Method of transformer short-circuit loss and open circuit loss, also relates to a kind of on-line measurement system.
Background technology
Transformer short-circuit is lost and open circuit loss is the important parameter of transformer, current transformer loss is mainly the short-circuit test passed through under off-line state and opens a way what experiment measurement was obtained, the measuring method can be measured conveniently for the transformer newly networked, but be uneconomic using the measuring method for operating transformer, both substantial amounts of manpower and materials had been wasted, again the continuity of influence power supply.
At present, it has been proposed that some be used for transformer loss on-line measurement method, including：
1. input and the difference of power output by measuring transformer, ask for the power attenuation of transformer, the method energy on-line measurement transformer loss, but can not measure zero load and the short circuit loss of transformer；
2. by circuit transformations, using the copper loss and the value of iron loss of summation on-line measurement transformer, the shortcoming of this method is that two groups of parameters of measurement differ also very little, and now error caused by measuring system influences very big to measurement accuracy when load change is smaller.
In general, these measuring methods by load change influenceed than it is larger and also be required for detect high voltage side of transformer voltage signal, it is not only uneconomical but also dangerous.
The content of the invention
In view of this, an object of the present invention is to provide the On-line Measuring Method of a kind of transformer short-circuit loss and open circuit loss, and the second object of the present invention is to provide the on-line measurement system of a kind of transformer short-circuit loss and open circuit loss.
The purpose of the present invention is achieved through the following technical solutions：
The On-line Measuring Method that the transformer short-circuit is lost and open circuit is lost, comprises the following steps：
Step one：Equivalent circuit of transformer is set up, the relational model between the short-circuit resistance and transformer primary, secondary voltage, electric current of transformer, and the relational model between transformer short-circuit resistance and short circuit loss and open circuit loss are obtained according to circuit model；
Relational model between the short-circuit resistance and transformer primary, secondary voltage, electric current is based on relationship below：
Figure 2011102734167100002DEST_PATH_IMAGE002
；
In formula,z 1For the impedance of first winding； 
Figure 2011102734167100002DEST_PATH_IMAGE004
、
Figure 2011102734167100002DEST_PATH_IMAGE006
For primary side voltage, current value；
Figure 2011102734167100002DEST_PATH_IMAGE008
、For secondary side voltage, current value；
Figure 2011102734167100002DEST_PATH_IMAGE012
、
Figure 2011102734167100002DEST_PATH_IMAGE014
It is secondary side voltage, electric current in primary side reduction value；
Figure 2011102734167100002DEST_PATH_IMAGE016
For exciting current；kFor no-load voltage ratio；z k For short-circuit impedance；
Relational model between the transformer short-circuit resistance and short circuit loss and open circuit loss is based on relationship below：
Short circuit loss：
Figure 2011102734167100002DEST_PATH_IMAGE018
,
In formula,=z k ,I 1NFor primary side rated current；
Figure 2011102734167100002DEST_PATH_IMAGE022
It is the ratio of the actual load current value of transformer and its rated value for load factor,
Figure 2011102734167100002DEST_PATH_IMAGE024
It is represented by
Figure DEST_PATH_IMAGE026
；
Open circuit loss：,
In formula,
Figure DEST_PATH_IMAGE030
For the ideal voltage source equal with high voltage side of transformer signal, for replacing high voltage side of transformer voltage signal；
Step 2：Pass through online acquisition transformer primary side voltage and secondary side voltage, current signal, the transformed voltage and current signal obtained available for mathematical operation, voltage and current signal is passed through into linear fit, with reference to transformer short-circuit resistance and transformer primary, secondary voltage, electric current between relation, obtain the value of the short-circuit resistance of distribution transformer；
Step 3：According to by step 1）Corresponding relation between obtained short-circuit resistance and short circuit loss and open circuit loss, obtains the concrete numerical value of short circuit loss and open circuit loss, realizes transformer short-circuit loss and the on-line measurement of open circuit loss.
Further, in step one, the short-circuit impedance is obtained as follows with its former and deputy polygonal voltage, the relational expression of electric current：
1）Following relational expression can be obtained according to the T-shaped equivalent-circuit model of transformer：
Figure DEST_PATH_IMAGE032
,
Wherein: z1For the impedance of first winding；z21For secondary winding impedance primary side reduction value；
Figure 394791DEST_PATH_IMAGE004
、
Figure 46352DEST_PATH_IMAGE006
For primary side voltage, current value；
Figure 652520DEST_PATH_IMAGE008
、
Figure 47730DEST_PATH_IMAGE010
For secondary side voltage, current value；
Figure 658840DEST_PATH_IMAGE012
、
Figure 746881DEST_PATH_IMAGE014
It is secondary side voltage, electric current in primary side reduction value；z mFor excitation impedance；
Figure 13915DEST_PATH_IMAGE016
For exciting current；kFor no-load voltage ratio；z 1+z 21For short-circuit impedance；
2）Orderz k =z 1+z 21, according to step 1）Following relational expression can be built：
Figure DEST_PATH_IMAGE034
；
3）According to step 2）The relational expression of acquisition and
Figure DEST_PATH_IMAGE036
,
Figure DEST_PATH_IMAGE038
, can obtain：
Figure DEST_PATH_IMAGE040
,
I.e. in formulaValue withValue it is linear, and no-load voltage ratio isz k  。
Further, the step 2 specifically includes following steps：
21）With an ideal voltage source equal with high voltage side of transformer signalU sInstead of high voltage side of transformer voltage signal；
22）Gather Circuit Fault on Secondary Transformer voltage signalU 2With secondary side current signalI 2；
23）By step 22）The secondary side signal of middle acquisition and the preferable constant pressure source for replacing primary side voltage signalU s Mathematic(al) manipulation is carried out, signal is obtained：U s-kU 2WithI 2/k, whereinkFor no-load voltage ratio；
24）According to step 23）The AC signal U of middle acquisitions-kU 2WithI 2/k, can be obtained by linear fit：
Figure DEST_PATH_IMAGE046
；
25）With reference to following two formula, the value that can obtain Transformer Short Circuit Impedance isz k =a,
Figure 963547DEST_PATH_IMAGE046
,
Figure 366847DEST_PATH_IMAGE040
。
Further, in step one, the relational expression between the transformer short-circuit resistance and short circuit loss and open circuit loss is obtained by following steps：
1）In the case where ignoring transformer dielectric loss and stray loss, the loss that distribution transformer is produced when running is divided into iron lossP FeAnd copper lossP Cu, the expression formula of total losses of transformer can be obtained：
Figure DEST_PATH_IMAGE048
,
Wherein：P 1For input power,P 2For power output；
2）Open circuit loss as claimed in claim 1P 0, open circuit loss is transformer secondary winding open circuit, and first winding adds the loss measured during rated voltage, is ignoring in the case that no-load current produces in first winding and be lost, is regarding open circuit loss as iron loss, can obtain its relational expression：
Figure DEST_PATH_IMAGE050
；
3）Short circuit lossP k For transformer secondary short circuit in winding, first winding pressurization makes the loss that primary side current is measured when reaching rated current.Visual short circuit loss is the copper loss under rated current, can obtain its relational expression：
Figure DEST_PATH_IMAGE052
,
Wherein：I 1N For primary side rated current；r 1+r 21For short-circuit resistance；
Figure 750424DEST_PATH_IMAGE022
It is the ratio of the actual load current value of transformer and its rated value for load factor.
4）According to step 3）It is middle to require, transformer copper loss can be obtained by following formula：
Figure DEST_PATH_IMAGE054
；
5）According to step 4）The relational expression of middle acquisition can obtain the on-line measurement of short circuit loss, step 4）In the relational expression of acquisitioni m Onlyi 15%-8% or so, can be neglected in formula two, three phases, obtain following relational expression：
Figure DEST_PATH_IMAGE056
,
Figure DEST_PATH_IMAGE058
,
Figure 65605DEST_PATH_IMAGE024
It is represented by：
Figure DEST_PATH_IMAGE060
；
6）According to step 1）In relational expression and step 2）In requirement and replace primary side voltage signal with desired voltage source signal, Transformers Iron Loss can be obtained by following formula：
Figure DEST_PATH_IMAGE062
,
According to step 2）With step 6）In relational expression, can obtain transformer open circuit loss relational expression it is as follows
Figure 927251DEST_PATH_IMAGE028
。
The second object of the present invention is achieved through the following technical solutions：
The on-line measurement system that the transformer short-circuit is lost and open circuit is lost, including
Modeling Calculation unit, set up equivalent circuit of transformer, the relational model between the short-circuit resistance and transformer primary, secondary voltage, electric current of transformer, and the relational model between transformer short-circuit resistance and short circuit loss and open circuit loss are obtained according to circuit model；
Online acquisition unit, for gathering transformer primary side voltage and secondary side voltage, current signal；
Short-circuit resistance value computing unit, by the transformer primary side voltage and secondary side voltage, current signal of online acquisition, the transformed voltage and current signal obtained available for mathematical operation, voltage and current signal is passed through into linear fit, with reference to transformer short-circuit resistance and transformer primary, secondary voltage, electric current between relational model, obtain value and the output of the short-circuit resistance of distribution transformer；
Short circuit loss and open circuit loss computing unit, according to the value of short-circuit resistance, and combine the relational model between transformer short-circuit resistance and short circuit loss and open circuit loss, calculating obtains short circuit loss and open circuit loss.
Further, the relational model between the short-circuit resistance and transformer primary, secondary voltage, electric current is based on relationship below：
Figure 450636DEST_PATH_IMAGE040
；
In formula,z 1For the impedance of first winding；
Figure 942797DEST_PATH_IMAGE004
、
Figure 918843DEST_PATH_IMAGE006
For primary side voltage, current value；
Figure 459546DEST_PATH_IMAGE008
、
Figure 666799DEST_PATH_IMAGE010
For secondary side voltage, current value；
Figure 1965DEST_PATH_IMAGE012
、
Figure 793204DEST_PATH_IMAGE014
It is secondary side voltage, electric current in primary side reduction value；For exciting current；kFor no-load voltage ratio；z k For short-circuit impedance；
Relational model between the transformer short-circuit resistance and short circuit loss and open circuit loss is based on relationship below：
Short circuit loss：
Figure 369996DEST_PATH_IMAGE018
,
In formula,
Figure 938380DEST_PATH_IMAGE020
=z k,I 1N
Figure DEST_PATH_IMAGE064
For primary side rated current；
Figure 154598DEST_PATH_IMAGE022
It is the ratio of the actual load current value of transformer and its rated value for load factor,
Figure 99420DEST_PATH_IMAGE024
It is represented by
Figure 451904DEST_PATH_IMAGE026
；
Open circuit loss：
Figure 955304DEST_PATH_IMAGE028
,
In formula,
Figure 393239DEST_PATH_IMAGE030
For the ideal voltage source equal with high voltage side of transformer signal, for replacing high voltage side of transformer voltage signal.
The beneficial effects of the invention are as follows：
1）The method of the present invention realizes the on-line measurement of its loss merely with transformer primary side current signal and secondary side voltage, current signal, substantially increases the security reliability of online measuring technique, reduce further the financial cost of online measuring technique；
2）The method of the present invention using ideal signal source due to replacing high voltage side of transformer voltage signal, in the case where not reducing measurement accuracy, overcomes the shortcoming that on-line measurement is carried out using high side voltage signal；
3）The method of the present invention implements easy, and implementation cost is low, it is easy to be converted into complete set of equipments, with higher application value.
Other advantages, target and the feature of the present invention will be illustrated in the following description to a certain extent, and to a certain extent, based on will be apparent to those skilled in the art to investigating hereafter, or it can be instructed from the practice of the present invention.The target and other advantages of the present invention can be realized and obtained by following specification and claims.
Brief description of the drawings
In order that the object, technical solutions and advantages of the present invention are clearer, below in conjunction with accompanying drawing, the present invention is described in further detail, wherein：
Fig. 1 equivalent circuit of transformer；
Fig. 2 Y, yn0 connection Transformer Winding wiring diagrams；
Fig. 3 Y, d11 connection Transformer Winding wiring diagrams.
Embodiment
Hereinafter with reference to accompanying drawing, the preferred embodiments of the present invention are described in detail.It should be appreciated that preferred embodiment is only for the explanation present invention, the protection domain being not intended to be limiting of the invention.
The On-line Measuring Method of transformer short-circuit loss and the open circuit loss of the present invention, comprises the following steps：
Step one：Equivalent circuit of transformer is set up, the relational model between the short-circuit resistance and transformer primary, secondary voltage, electric current of transformer, and the relational model between transformer short-circuit resistance and short circuit loss and open circuit loss are obtained according to circuit model；
Relational model between the short-circuit resistance and transformer primary, secondary voltage, electric current is based on relationship below：
Figure 813856DEST_PATH_IMAGE040
；
In formula, z1For the impedance of first winding；
Figure 348742DEST_PATH_IMAGE004
、
Figure 196613DEST_PATH_IMAGE006
For primary side voltage, current value；
Figure 121843DEST_PATH_IMAGE008
、
Figure 408468DEST_PATH_IMAGE010
For secondary side voltage, current value；
Figure 735544DEST_PATH_IMAGE012
、
Figure 82212DEST_PATH_IMAGE014
It is secondary side voltage, electric current in primary side reduction value；
Figure 494739DEST_PATH_IMAGE016
For exciting current；kFor no-load voltage ratio；z k For short-circuit impedance；
Relational model between the transformer short-circuit resistance and short circuit loss and open circuit loss is based on relationship below：
Short circuit loss：
Figure 257159DEST_PATH_IMAGE018
,
In formula,
Figure 2523DEST_PATH_IMAGE020
=z k ,I 1N For primary side rated current；It is the ratio of the actual load current value of transformer and its rated value for load factor,
Figure 357598DEST_PATH_IMAGE024
It is represented by
Figure 986025DEST_PATH_IMAGE026
；
Open circuit loss：,
In formula,
Figure 710585DEST_PATH_IMAGE030
For the ideal voltage source equal with high voltage side of transformer signal, for replacing high voltage side of transformer voltage signal；
Step 2：Pass through online acquisition transformer primary side voltage and secondary side voltage, current signal, the transformed voltage and current signal obtained available for mathematical operation, voltage and current signal is passed through into linear fit, with reference to transformer short-circuit resistance and transformer primary, secondary voltage, electric current between relation, obtain the value of the short-circuit resistance of distribution transformer；
Specifically, the step 2 specifically includes following steps：
21）With an ideal voltage source equal with high voltage side of transformer signalUsInstead of high voltage side of transformer voltage signal；
22）Gather Circuit Fault on Secondary Transformer voltage signalU 2With secondary side current signalI 2；Change ideal voltage source voltage in the case of the load of single-phase transformer, measurement different loads within the specific limits
Figure DEST_PATH_IMAGE066
And the secondary side voltage of transformer
Figure DEST_PATH_IMAGE068
, secondary side current
Figure DEST_PATH_IMAGE070
, wherein
Figure DEST_PATH_IMAGE072
=1,2,3 ... n, n are pendulous frequency;
23）By step 22）The secondary side signal of middle acquisition and the preferable constant pressure source for replacing primary side voltage signalU s Mathematic(al) manipulation is carried out, signal is obtained：It can obtain
Figure DEST_PATH_IMAGE074
With
Figure DEST_PATH_IMAGE076
, whereinkFor no-load voltage ratio；
24）According to step 23）The AC signal of middle acquisitionWith
Figure 783190DEST_PATH_IMAGE076
, withFor dependent variable,
Figure 43587DEST_PATH_IMAGE078
It can be obtained to carry out linear fit from variable：
Figure 902958DEST_PATH_IMAGE046
；
25）With reference to following two formula, the value that can obtain Transformer Short Circuit Impedance isz k =a,
Figure DEST_PATH_IMAGE080
,
Figure DEST_PATH_IMAGE082
。
Step 3：According to by step 1）Corresponding relation between obtained short-circuit resistance and short circuit loss and open circuit loss, obtains the concrete numerical value of short circuit loss and open circuit loss, realizes transformer short-circuit loss and the on-line measurement of open circuit loss.
On further illustrating for step one：
A. in step 1）In, the short-circuit impedance is obtained as follows with its former and deputy polygonal voltage, the relational expression of electric current：
1）Accompanying drawing 1 is the T-shaped equivalent-circuit model figure of single-phase transformer, and following relational expression can be obtained according to the T-shaped equivalent-circuit model of transformer：
,
Wherein: z 1For the impedance of first winding；z 21For secondary winding impedance primary side reduction value；
Figure 574111DEST_PATH_IMAGE004
、
Figure 311385DEST_PATH_IMAGE006
For primary side voltage, current value；、
Figure 352339DEST_PATH_IMAGE010
For secondary side voltage, current value；、
Figure 894496DEST_PATH_IMAGE014
It is secondary side voltage, electric current in primary side reduction value；z mFor excitation impedance；
Figure 87580DEST_PATH_IMAGE016
For exciting current；kFor no-load voltage ratio；z 1+z 21For short-circuit impedance；
2）Orderz k =z 1+z 21, according to step 1）Following relational expression can be built：
Figure 226437DEST_PATH_IMAGE034
；
3）According to step 2）The relational expression of acquisition and
Figure 809866DEST_PATH_IMAGE036
,
Figure 121898DEST_PATH_IMAGE038
, can obtain：
Figure 107172DEST_PATH_IMAGE040
,
When transformer is operated in the range of linearity of magnetization curve, it is believed that excitation impedance is constant, and because primary side impedance is much smaller than excitation impedance, so exciting current is proportional to
Figure DEST_PATH_IMAGE086
, it is approximately proportional to, therefore exciting current
Figure DEST_PATH_IMAGE090
It is believed that it is approximate constant, due to transformer first side winding impedancez 1It is a constant value, therefore in above formulaIt can be considered an approximate constant amount.I.e. in formula
Figure DEST_PATH_IMAGE094
Value with
Figure DEST_PATH_IMAGE096
Value it is linear, and no-load voltage ratio isz k  。
B. in step 1）In, the relational expression between the transformer short-circuit resistance and short circuit loss and open circuit loss is obtained by following steps：
1）In the case where ignoring transformer dielectric loss and stray loss, the loss that distribution transformer is produced when running is divided into iron lossP FeAnd copper lossP Cu, the expression formula of total losses of transformer can be obtained：
Figure DEST_PATH_IMAGE098
,
Wherein：P 1For input power,P 2For power output；
2）Foregoing open circuit lossP 0, open circuit loss is transformer secondary winding open circuit, and first winding adds the loss measured during rated voltage, is ignoring in the case that no-load current produces in first winding and be lost, is regarding open circuit loss as iron loss, can obtain its relational expression：
Figure 102416DEST_PATH_IMAGE050
；
3）Short circuit is damagedP kFor transformer secondary short circuit in winding, first winding pressurization makes the loss that primary side current is measured when reaching rated current.Visual short circuit loss is the copper loss under rated current, can obtain its relational expression：
Figure 235457DEST_PATH_IMAGE052
,
Wherein：I 1N For primary side rated current；r 1+r 2For short-circuit resistance；
Figure 288864DEST_PATH_IMAGE022
It is the ratio of the actual load current value of transformer and its rated value for load factor.
4）According to step 3）It is middle to require, transformer copper loss can be obtained by following formula：
Figure DEST_PATH_IMAGE100
；
5）According to step 4）The relational expression of middle acquisition can obtain the on-line measurement of short circuit loss, step 4）In the relational expression of acquisitioni mOnlyi 15%-8% or so, can be neglected in formula two, three phases, obtain following relational expression：
Figure DEST_PATH_IMAGE102
,
Figure DEST_PATH_IMAGE104
,
Figure 754743DEST_PATH_IMAGE024
It is represented by：
Figure DEST_PATH_IMAGE106
；
6）According to above-mentioned steps 1）In relational expression and step 2）In requirement and replace primary side voltage signal with desired voltage source signal, Transformers Iron Loss can be obtained by following formula：
Figure DEST_PATH_IMAGE108
,
According to step 2）With step 6）In relational expression, can obtain transformer open circuit loss relational expression it is as follows
Figure DEST_PATH_IMAGE110
。
On further illustrating for step 2：
A. specifically, the three-phase transformer short-circuit impedance of Y, yn0 connection can be obtained as follows：
1）Accompanying drawing 2 is Y, the three-phase transformer winding connection figure of yn0 connections, with a three-phase ideal voltage source equal with three-phase transformer high side voltage signal
Figure 297719DEST_PATH_IMAGE066
Instead of single-phase transformer high side voltage signal：
Figure DEST_PATH_IMAGE112
、
Figure DEST_PATH_IMAGE114
、, then measure three-phase transformer low-pressure side voltage in the case of different loads：、
Figure DEST_PATH_IMAGE120
、, low-pressure side electric current：
Figure DEST_PATH_IMAGE124
、、
Figure DEST_PATH_IMAGE128
, whereini=1,2,3, n。
2）22 in step 2）、23）、24）It can obtain：
Figure DEST_PATH_IMAGE130
、
Figure DEST_PATH_IMAGE132
、
Figure DEST_PATH_IMAGE134
, using it as from variable, with
Figure DEST_PATH_IMAGE136
、
Figure DEST_PATH_IMAGE138
、
Figure DEST_PATH_IMAGE140
Following three relational expression can be obtained by carrying out linear fit for dependent variable：
Figure DEST_PATH_IMAGE142
Figure DEST_PATH_IMAGE144
Figure DEST_PATH_IMAGE146
Wherein,kFor the no-load voltage ratio of transformer, it can be obtained by three above relational expressiona 1、a 2、a 3Three values, calculate the average value of three, the value is the short-circuit impedance value of this Three-Phase Distribution Transformers, i.e.,：
Figure DEST_PATH_IMAGE148
The three-phase transformer short-circuit impedance of B.Y, d connection can be obtained as follows：
1) accompanying drawing 3 is Y, and the three-phase transformer winding connection figure of d11 connections is converted into the secondary side line current of the three-phase transformer measured in phase current, figure,i La、i Lb、i LcFor line current, it is represented by：
Figure DEST_PATH_IMAGE150
;
2）By accompanying drawing 3, following relational expression can be obtained according to Kirchhoff's law：
Figure DEST_PATH_IMAGE152
,
3）According to above-mentioned steps 1）With step 2）The relational expression of acquisition can obtain following relational expression：
Figure DEST_PATH_IMAGE154
;
4）According to Y, the step 2 of the three-phase transformer short-circuit impedance computational methods of yn0 connections）The three-phase transformer short-circuit impedance value of Yd or Ydn connections can be obtained.
Thought based on the above method, a kind of on-line measurement system of transformer short-circuit loss and open circuit loss proposed by the present invention, including
Modeling Calculation unit, set up equivalent circuit of transformer, the relational model between the short-circuit resistance and transformer primary, secondary voltage, electric current of transformer, and the relational model between transformer short-circuit resistance and short circuit loss and open circuit loss are obtained according to circuit model；
Online acquisition unit, for gathering transformer primary side voltage and secondary side voltage, current signal；
Short-circuit resistance value computing unit, by the transformer primary side voltage and secondary side voltage, current signal of online acquisition, the transformed voltage and current signal obtained available for mathematical operation, voltage and current signal is passed through into linear fit, with reference to transformer short-circuit resistance and transformer primary, secondary voltage, electric current between relational model, obtain value and the output of the short-circuit resistance of distribution transformer；
Short circuit loss and open circuit loss computing unit, according to the value of short-circuit resistance, and combine the relational model between transformer short-circuit resistance and short circuit loss and open circuit loss, calculating obtains short circuit loss and open circuit loss.
Wherein, the relational model between the short-circuit resistance and transformer primary, secondary voltage, electric current is based on relationship below：
Figure 151012DEST_PATH_IMAGE040
；
In formula,z 1For the impedance of first winding；
Figure 8110DEST_PATH_IMAGE004
、
Figure 286686DEST_PATH_IMAGE006
For primary side voltage, current value；
Figure 564DEST_PATH_IMAGE008
、
Figure 45881DEST_PATH_IMAGE010
For secondary side voltage, current value；
Figure 441090DEST_PATH_IMAGE012
、
Figure 52200DEST_PATH_IMAGE014
It is secondary side voltage, electric current in primary side reduction value；
Figure 140242DEST_PATH_IMAGE016
For exciting current；kFor no-load voltage ratio；z k For short-circuit impedance；
Relational model between the transformer short-circuit resistance and short circuit loss and open circuit loss is based on relationship below：
Short circuit loss：
Figure DEST_PATH_IMAGE156
,
In formula,
Figure 469592DEST_PATH_IMAGE020
=z k ,I 1N For primary side rated current；It is the ratio of the actual load current value of transformer and its rated value for load factor,
Figure 635573DEST_PATH_IMAGE024
It is represented by
Figure 894516DEST_PATH_IMAGE026
；
Open circuit loss：
Figure 383266DEST_PATH_IMAGE028
,
In formula,
Figure 448174DEST_PATH_IMAGE030
For the ideal voltage source equal with high voltage side of transformer signal, for replacing high voltage side of transformer voltage signal.
What is finally illustrated is, the above embodiments are merely illustrative of the technical solutions of the present invention and it is unrestricted, although the present invention is described in detail with reference to preferred embodiment, it will be understood by those within the art that, technical scheme can be modified or equivalent, without departing from the objective and scope of the technical program, it all should cover among scope of the presently claimed invention.

Claims (6)

  1. The On-line Measuring Method that 1. transformer short-circuit is lost and open circuit is lost, it is characterised in that：Comprise the following steps：
    Step one：Equivalent circuit of transformer is set up, the relational model between the short-circuit resistance and transformer primary, secondary voltage, electric current of transformer, and the relational model between transformer short-circuit resistance and short circuit loss and open circuit loss are obtained according to circuit model；
    Relational model between the short-circuit resistance and transformer primary, secondary voltage, electric current is based on relationship below：
    Figure 2011102734167100001DEST_PATH_IMAGE001
    ；
    In formula, z1For the impedance of first winding； 、
    Figure 2011102734167100001DEST_PATH_IMAGE003
    For primary side voltage, current value；
    Figure 124035DEST_PATH_IMAGE004
    、
    Figure 2011102734167100001DEST_PATH_IMAGE005
    For secondary side voltage, current value；
    Figure 630365DEST_PATH_IMAGE006
    、
    Figure 2011102734167100001DEST_PATH_IMAGE007
    It is secondary side voltage, electric current in primary side reduction value；
    Figure 130616DEST_PATH_IMAGE008
    For exciting current；kFor no-load voltage ratio；zkFor short-circuit impedance；
    Relational model between the transformer short-circuit resistance and short circuit loss and open circuit loss is based on relationship below：
    Short circuit loss,
    In formula,
    Figure 551233DEST_PATH_IMAGE010
    =zk,I 1N For primary side rated current；
    Figure 2011102734167100001DEST_PATH_IMAGE011
    It is the ratio of the actual load current value of transformer and its rated value for load factor,
    Figure 86120DEST_PATH_IMAGE012
    It is represented by；
    Open circuit loss
    Figure 261886DEST_PATH_IMAGE014
    ,
    In formula,
    Figure 2011102734167100001DEST_PATH_IMAGE015
    For the ideal voltage source equal with high voltage side of transformer signal, for replacing high voltage side of transformer voltage signal；
    Step 2：Pass through online acquisition transformer primary side voltage and secondary side voltage, current signal, the transformed voltage and current signal obtained available for mathematical operation, voltage and current signal is passed through into linear fit, with reference to transformer short-circuit resistance and transformer primary, secondary voltage, electric current between relation, the value of the short-circuit resistance of distribution transformer is obtained in real time；
    Step 3：According to by step 1）Corresponding relation between obtained short-circuit resistance and short circuit loss and open circuit loss, obtains the concrete numerical value of short circuit loss and open circuit loss, realizes transformer short-circuit loss and the on-line measurement of open circuit loss.
  2. 2. transformer short-circuit loss according to claim 1 and the On-line Measuring Method of open circuit loss, it is characterised in that：
    In step one, the short-circuit impedance is obtained as follows with its former and deputy polygonal voltage, the relational expression of electric current：
    1）Following relational expression can be obtained according to the T-shaped equivalent-circuit model of transformer：
    Figure 747969DEST_PATH_IMAGE016
    ,
    Wherein:z1For the impedance of first winding；z21For secondary winding impedance primary side reduction value；
    Figure 972277DEST_PATH_IMAGE002
    、
    Figure 33774DEST_PATH_IMAGE003
    For primary side voltage, current value；
    Figure 380441DEST_PATH_IMAGE004
    、
    Figure 792968DEST_PATH_IMAGE005
    For secondary side voltage, current value；
    Figure 883284DEST_PATH_IMAGE006
    、It is secondary side voltage, electric current in primary side reduction value；
    Figure 2011102734167100001DEST_PATH_IMAGE017
    For excitation impedance；
    Figure 316856DEST_PATH_IMAGE008
    For exciting current；kFor no-load voltage ratio；z 1+z 21For short-circuit impedance；
    2）Orderz k = z 1+z 21, according to step 1）Following relational expression can be built：
    Figure 216679DEST_PATH_IMAGE018
    ；
    3）According to step 2）The relational expression of acquisition and
    Figure 2011102734167100001DEST_PATH_IMAGE019
    ,
    Figure 346571DEST_PATH_IMAGE020
    , can obtain：
    Figure 648240DEST_PATH_IMAGE001
    ,
    I.e. in formula
    Figure 2011102734167100001DEST_PATH_IMAGE021
    Value with
    Figure 71131DEST_PATH_IMAGE022
    Value it is linear, and no-load voltage ratio be zk。
  3. 3. transformer short-circuit loss according to claim 2 and the On-line Measuring Method of open circuit loss, it is characterised in that：The step 2 specifically includes following steps：
    21）With an ideal voltage source equal with high voltage side of transformer signalU s Instead of high voltage side of transformer voltage signal；
    22）Gather Circuit Fault on Secondary Transformer voltage signalU 2With secondary side current signalI 2；
    23）By step 22）The secondary side signal of middle acquisition carries out mathematic(al) manipulation with replacing the preferable constant pressure source Us of primary side voltage signal, obtains signal：U s -kU 2WithI 2/k, whereinkFor no-load voltage ratio；
    24）According to step 23）The AC signal of middle acquisitionU s-kU 2WithI 2/k, can be obtained by linear fit：
    Figure 2011102734167100001DEST_PATH_IMAGE023
    ；
    25）With reference to following two formula, the value that can obtain Transformer Short Circuit Impedance isz k =a,
    Figure 520567DEST_PATH_IMAGE023
    ,
    Figure 952685DEST_PATH_IMAGE001
    。
  4. 4. the On-line Measuring Method of the transformer short-circuit loss and open circuit loss according to claim 1 or 2 or 3, it is characterised in that：In step one, the relational expression between the transformer short-circuit resistance and short circuit loss and open circuit loss is obtained by following steps：
    1）In the case where ignoring transformer dielectric loss and stray loss, the loss that distribution transformer is produced when running is divided into iron lossP Fe And copper lossP Cu , the expression formula of total losses of transformer can be obtained：
    Figure 843281DEST_PATH_IMAGE024
    ,
    Wherein：P 1For input power,P 2For power output；
    2）Open circuit loss as claimed in claim 1P 0, open circuit loss is transformer secondary winding open circuit, and first winding adds the loss measured during rated voltage, is ignoring in the case that no-load current produces in first winding and be lost, is regarding open circuit loss as iron loss, can obtain its relational expression：
    Figure 2011102734167100001DEST_PATH_IMAGE025
    ；
    3）Short circuit lossP kFor transformer secondary short circuit in winding, first winding pressurization makes the loss that primary side current is measured when reaching rated current；
    Copper loss under short circuit loss is regarded as rated current, can obtain its relational expression：
    Figure 201187DEST_PATH_IMAGE026
    ,
    Wherein：For primary side rated current；r 1+r 21For short-circuit resistance；
    Figure 872340DEST_PATH_IMAGE011
    It is the ratio of the actual load current value of transformer and its rated value for load factor；
    4）According to step 3）It is middle to require, transformer copper loss can be obtained by following formula：
    ；
    5）According to step 4）The relational expression of middle acquisition can obtain the on-line measurement of short circuit loss, step 4）In the relational expression of acquisitioni m Onlyi 15%-8% or so, can be neglected in formula two, three phases, obtain following relational expression：
    Figure 2011102734167100001DEST_PATH_IMAGE029
    ,
    Figure 118831DEST_PATH_IMAGE030
    ,
    Figure 86787DEST_PATH_IMAGE012
    It is represented by：
    Figure DEST_PATH_IMAGE031
    ；
    6）According to step 1）In relational expression and step 2）In requirement and replace primary side voltage signal with desired voltage source signal, Transformers Iron Loss can be obtained by following formula：
    Figure 245236DEST_PATH_IMAGE032
    ,
    According to step 2）With step 6）In relational expression, can obtain transformer open circuit loss relational expression it is as follows
    Figure DEST_PATH_IMAGE033
    。
  5. The on-line measurement system that 5. transformer short-circuit is lost and open circuit is lost, it is characterised in that：The system includes
    Modeling Calculation unit, set up equivalent circuit of transformer, the relational model between the short-circuit resistance and transformer primary, secondary voltage, electric current of transformer, and the relational model between transformer short-circuit resistance and short circuit loss and open circuit loss are obtained according to circuit model；
    Online acquisition unit, for gathering transformer primary side voltage and secondary side voltage, current signal；
    Short-circuit resistance value computing unit, by the transformer primary side voltage and secondary side voltage, current signal of online acquisition, the transformed voltage and current signal obtained available for mathematical operation, voltage and current signal is passed through into linear fit, with reference to transformer short-circuit resistance and transformer primary, secondary voltage, electric current between relational model, obtain value and the output of the short-circuit resistance of distribution transformer；
    Short circuit loss and open circuit loss computing unit, according to the value of short-circuit resistance, and combine the relational model between transformer short-circuit resistance and short circuit loss and open circuit loss, calculating obtains short circuit loss and open circuit loss.
  6. 6. the On-line Measuring Method of the transformer short-circuit loss and open circuit loss according to claim 1 or 2 or 3, it is characterised in that：Relational model between the short-circuit resistance and transformer primary, secondary voltage, electric current is based on relationship below：
    Figure 520622DEST_PATH_IMAGE034
    ；
    In formula,z 1For the impedance of first winding；
    Figure 385809DEST_PATH_IMAGE002
    、
    Figure 586984DEST_PATH_IMAGE003
    For primary side voltage, current value；
    Figure 170412DEST_PATH_IMAGE004
    、
    Figure 420127DEST_PATH_IMAGE005
    For secondary side voltage, current value；
    Figure 467718DEST_PATH_IMAGE006
    、
    Figure 777476DEST_PATH_IMAGE007
    It is secondary side voltage, electric current in primary side reduction value；
    Figure 848201DEST_PATH_IMAGE008
    For exciting current；kFor no-load voltage ratio；z k For short-circuit impedance；
    Relational model between the transformer short-circuit resistance and short circuit loss and open circuit loss is based on relationship below：
    Short circuit loss：
    Figure DEST_PATH_IMAGE035
    ,
    In formula,
    Figure 963924DEST_PATH_IMAGE010
    =z k ,I 1NFor primary side rated current；
    Figure 387994DEST_PATH_IMAGE011
    It is the ratio of the actual load current value of transformer and its rated value for load factor,
    Figure 868654DEST_PATH_IMAGE012
    It is represented by
    Figure 161095DEST_PATH_IMAGE036
    ；
    Open circuit loss：
    Figure DEST_PATH_IMAGE037
    ,
    In formula,
    Figure 80509DEST_PATH_IMAGE015
    For the ideal voltage source equal with high voltage side of transformer signal, for replacing high voltage side of transformer voltage signal.
CN2011102734167A 2011-09-15 2011-09-15 Method and system for online measurement of short-circuit loss and open-circuit loss of transformer Pending CN102435858A (en)

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CN113567747A (en) * 2021-07-26 2021-10-29 四川英杰电气股份有限公司 Silicon core resistance value detection circuit, method and system
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CN103779835A (en) * 2014-02-18 2014-05-07 国家电网公司 Transformer winding turn-to-turn short circuit relay protection method based on iron loss reactive power characteristic
CN105044470A (en) * 2015-06-30 2015-11-11 同济大学 Method for detecting DC capacity of current transformer based on resonance principles
CN105044470B (en) * 2015-06-30 2017-12-26 同济大学 A kind of current transformer DC capacitor capacity check method based on resonance principle
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CN105067878A (en) * 2015-07-22 2015-11-18 国家电网公司 Transformer power characteristic live-line tester
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CN105510742B (en) * 2015-12-08 2018-03-27 云南电力试验研究院(集团)有限公司 A kind of test method tested using low-frequency power transformer C-V characteristic and analysis calculation method
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CN106324354B (en) * 2016-08-29 2017-05-31 张正 A kind of transformer leakage impedance detection method and device, fault detection method and device
CN106646283A (en) * 2017-01-22 2017-05-10 保定天威保变电气股份有限公司 Method of determining magnetic conductive member stray loss
CN106646283B (en) * 2017-01-22 2019-01-11 保定天威保变电气股份有限公司 A kind of method of determining conducting magnetic component stray loss
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