CN104407267A - Transformer fault detection method - Google Patents

Abstract

The invention discloses a transformer fault detection method. The method based on a transformer electrical parameter fault feature library includes transformer model building, transformer electrical parameter fault feature library establishment and fault detection. The method is implemented in an all-digital manner, various transformer faults such as external open circuit fault, internal open circuit fault, to-earth short-circuit fault, turn-earth short-circuit fault, turn-to-turn short-circuit fault, external phase fault and internal phase fault can be judged accurately, and proper expansion can be performed according to actual demand. The method is widely applicable to transformers such as oil immersed transformers, water cooled transformers, air cooled transformers and air and water cooled transformers, occurrence of the transformer faults is prevented and judged to the uttermost extent, the technical problems about parameter detection, fault protection and fault diagnosis are solved, safety and maintainability of the system are improved, and difficulty and consumed time for system troubleshooting are lowered.

Description

A kind of transformer fault detection method

Technical field

The invention belongs to transformer and fault diagnosis field, be specifically related to a kind of transformer fault detection method.

Background technology

At present, transformer fault diagnosis mainly adopts dissolved gas analysis method (DGA), but dissolved gas analysis method can only be applicable to oil-filled transformer, the transformer of the types such as water cooled transformer, air cooled transformer and air water cooling formula transformer cannot be widely used in.And dissolved gas analysis method can only after fault occurs, when Gases Dissolved in Transformer Oil occurs significantly to change, trouble-saving expansion, often poor effect passively.

The method can not initiatively trouble-saving generation, and fault reaction speed is comparatively slow, cannot detect transformer electrical quantity, also cannot tracing trouble type and position of failure point.

Summary of the invention

The object of the invention is to overcome existing for prior art can not initiatively trouble-saving generation, fault reaction speed is slower, transformer electrical quantity cannot be detected, also cannot the shortcoming of tracing trouble type and position of failure point, a kind of transformer fault detection method is proposed, oil-filled transformer can be widely used in, water cooled transformer, the transformer of the types such as air cooled transformer and air water cooling formula transformer, the generation of transformer fault can be judged in advance, prevention judges the generation of transformer fault to greatest extent, solve parameter detecting simultaneously, the technical matters of emergency protection and fault diagnosis, improve security and the maintainability of system, the difficulty reducing system investigation fault and the time spent.

Technical scheme of the present invention is:

A kind of transformer fault detection method, comprises the following steps:

Step 1, set up transformer fault model: for the transformer type that will detect, analyzed the type of the relay protection that the change of transformer each phase winding line voltage waveform and line current waveform before and after various fault and this fault trigger by theoretical analysis or Softwares of System Simulation;

Step 2, set up transformer electrical quantity knowledge base: the type of the relay protection that change and this fault of transformer each phase winding line voltage waveform and line current waveform before and after various fault trigger is analyzed, system of selection is simple, the fault signature of successful, is encoded into fault signature identification code and is cured in transformer electrical quantity knowledge base and goes;

Wherein, transformer fault storehouse comprises following 7 contents: longitudinal difference protection identification code, zero-sequence current protection identification code, current effective value identification code, voltage effective value identification code, excess current identification code, current-unbalance degree identification code and secondary harmonic brake code; Specific as follows:

Identification code one. longitudinal difference protection identification code is 1 bit, this position reflection transformer differential protection state; Transformer has a phase generation Current Differential Protection at least, and this position gets 1; Only have transformer current longitudinal difference protection not to occur, this just gets 0;

Identification code two. zero-sequence current protection identification code is 3 bits, the 0th reflection star secondary zero-sequence current protection state, the 1st reflection triangle secondary zero-sequence current protection state, the 2nd reflection former limit zero-sequence current protection state; If during certain limit winding generation zero-sequence current protection, the identification code on the corresponding position of this limit winding is 1; If when zero-sequence current protection does not occur certain limit winding, the identification code on the corresponding position of this limit winding is 0;

Identification code three. current effective value identification code is 9 decimal numbers, 0th reflection secondary star c2 line current effective value, 1st reflection secondary star b2 line current effective value, 2nd reflection secondary star a2 line current effective value, 3rd reflection secondary triangle c1 line current effective value, 4th reflection secondary triangle b1 line current effective value, 5th reflection secondary triangle a1 line current effective value, 6th reflection former limit triangle C line current effective value, 7th reflection former limit triangle B line current effective value, 8th reflection former limit triangle A line current effective value, current effective value identification code is mainly used in the relative size reflecting each line current effective value, to diagnose transformer open circuit fault, if certain cover winding current effective value is 0, on corresponding position, line current identification code is 0, and other line current effective value of this cover winding is identical, and corresponding positions identification code is 1, if certain cover winding current effective value is not 0, then this cover winding three line current effective value identification codes are all 2,

Identification code four. voltage effective value identification code is 3 decimal numbers, 0th reflection former limit triangle C line voltage effective value, 1st reflection former limit triangle B line voltage effective value, the 2nd (most significant digit) reflects former limit triangle A line voltage effective value; Voltage effective value identification code is mainly used in distinguishing the single-phase outside open circuit of former limit delta windings and former limit delta windings two-phase internal break; There are two kinds of situations in former sideline voltage effective value, the wired voltage effective value of institute is identical, and voltage effective value identification code every is all 1; A certain line voltage effective value is 2 times of all the other line voltage effective values, then this line voltage effective value identification code is 2, and all the other positions are 1;

Identification code five. excess current identification code is 9 bits, 0th reflection secondary star c2 line current overcurrent condition, 1st reflection secondary star b2 line current overcurrent condition, 2nd reflection secondary star a2 line current overcurrent condition, 3rd reflection secondary triangle c1 line current overcurrent condition, 4th reflection secondary triangle b1 line current overcurrent condition, 5th reflection secondary triangle a1 line current overcurrent condition, 6th reflection former limit triangle C line current overcurrent condition, 7th reflection former limit triangle B line current overcurrent condition, 8th reflection former limit triangle A line current overcurrent condition, excess current identification code mainly for detection of each line current whether overcurrent, to diagnose transformer external short circuit fault, if certain line current exists excess current, then corresponding positions excess current identification code is 1, otherwise is 0,

Identification code six. current-unbalance degree identification code is 6 decimal numbers, 0th the unbalanced degree of reflection secondary star c2 line current, 1st the unbalanced degree of reflection secondary star b2 line current, 2nd the unbalanced degree of reflection secondary star a2 line current, 3rd the unbalanced degree of reflection secondary triangle c1 line current, 4th the unbalanced degree of reflection secondary triangle b1 line current, the 5th the unbalanced degree of reflection secondary triangle a1 line current; Current-unbalance degree identification code is used for diagnosing the unconspicuous fault of current characteristic; For certain a set of winding, be greater than the mean value of this cover winding wire current effective value as crossed a certain line current, then current-unbalance degree identification code gets 2; If a certain line current equals the mean value of this cover winding wire current effective value, current-unbalance degree identification code gets 1; If a certain line current is less than the mean value of this cover winding wire current effective value, current-unbalance degree identification code gets 0;

Identification code seven. secondary harmonic brake code is 1 bit; Former limit has at least a line current second harmonic to exceed setting valve, and this position gets 1; When only having former sideline electric current second harmonic all not exceed setting valve, this just gets 0; Whether its reflection transformer exists excitation surge current; When transformer produces excitation surge current, transformer differential protection meeting malfunction, secondary harmonic brake code is just used to realize transformer differential protection braking, prevents malfunction;

Step 3, gather original signal, the transformer electrical quantity knowledge base that the transformer fault model set up based on step 1 and step 2 are set up carries out the detection of transformer fault type and position of failure point: calculate outlet voltage effective value, line current effective value, line voltage phase angle, line current phasing degree, active power, reactive power, applied power, power factor, power-factor angle etc. by parameter detecting detection algorithm; Then calculating two sections of ratio formula longitudinal difference protections, zero-sequence component protection, overload protection, calculation of over current protection by fault protection algorithms, preventing protective relaying maloperation from doing by calculating excitation surge current simultaneously; Following fault is detected: outside open circuit fault, internal break fault, shorted to earth fault, all over the ground short trouble, shorted-turn fault, outside phase fault, inner phase fault, overload fault, over current fault finally by looking into transformer fault feature database.

In above-mentioned a kind of transformer fault detection method, described step 1 is selective system simulation software MATLAB for the transformer fault Developing Transformer fault model of such as Types Below, and selected transformer fault type comprises: outside open circuit fault, internal break fault, shorted to earth fault, all over the ground short trouble, shorted-turn fault, outside phase fault and inner phase fault; Transformer fault model downloads in dSpace semi-physical emulation platform to produce analogue transformer line pressure-wire current waveform for exploitation, debugging and checking by debugging computer.

The present invention has as follows a little: the transformer 1, being widely used in the types such as oil-filled transformer, water cooled transformer, air cooled transformer and air water cooling formula transformer; 2, judge the generation of transformer fault in advance, prevention judges the generation of transformer fault to greatest extent; 3, Digital Implementation parameter detecting, emergency protection and fault diagnosis, device can also increase the content that will detect according to actual needs; 4, online real-time parameter detection, fault diagnosis and emergency protection, sensing range is large, and protection domain is wide, and fault diagnosis is clear and definite, improves security and the maintainability of system, reduces the difficulty of system investigation fault and the time spent.

Accompanying drawing explanation

Fig. 1 is exploitation involved in the present invention, debugging and verification platform schematic diagram.

Fig. 2 is transformer model schematic diagram involved in the present invention.

Fig. 3 is transformer electrical quantity knowledge base Establishing process sketch involved in the present invention.

Fig. 4 is transformer fault testing process sketch involved in the present invention.

Fig. 5 is transformer fault overhaul flow chart involved in the present invention.

Fig. 6 is transformer fault diagnosis process flow diagram involved in the present invention.

Embodiment

A kind of transformer fault detection method of the present invention, to be described for detection Dd0y11 transformer, is implemented as follows:

Step 1, transformer model are set up and are comprised following steps: selective system simulation software MATLAB is for the transformer fault Developing Transformer fault model of such as Types Below, and selected transformer fault type comprises: outside open circuit fault, internal break fault, shorted to earth fault, all over the ground short trouble, shorted-turn fault, outside phase fault and inner phase fault.Transformer fault model downloads in dSpace semi-physical emulation platform to produce analogue transformer line pressure-wire current waveform for exploitation, debugging and checking by debugging computer.Exploitation, debugging and verification platform are shown in Fig. 1, and transformer fault model schematic is shown in Fig. 2.

Step 2, transformer electrical quantity knowledge base are set up and are comprised following steps: according to the development process shown in Fig. 3; through debugging and verification, transformer fault storehouse comprises following 7 contents: longitudinal difference protection identification code, zero-sequence current protection identification code, current effective value identification code, voltage effective value identification code, excess current identification code, current-unbalance degree identification code and secondary harmonic brake code.

1. longitudinal difference protection identification code is 1 bit, this position reflection transformer differential protection state.Transformer has a phase generation Current Differential Protection at least, and this position gets 1; Only have transformer current longitudinal difference protection not to occur, this just gets 0.

2. zero-sequence current protection identification code is 3 bits; 0th (lowest order) reflects star secondary zero-sequence current protection state; 1st (interposition) reflects triangle secondary zero-sequence current protection state, and the 2nd (most significant digit) reflects former limit zero-sequence current protection state.If during certain limit winding generation zero-sequence current protection, the identification code on the corresponding position of this limit winding is 1; If when zero-sequence current protection does not occur certain limit winding, the identification code on the corresponding position of this limit winding is 0.

3. current effective value identification code is 9 decimal numbers, 0th (lowest order) reflects secondary star c2 line current effective value, 1st reflection secondary star b2 line current effective value, 2nd reflection secondary star a2 line current effective value, 3rd reflection secondary triangle c1 line current effective value, 4th reflection secondary triangle b1 line current effective value, 5th reflection secondary triangle a1 line current effective value, 6th reflection former limit triangle C line current effective value, 7th reflection former limit triangle B line current effective value, 8th (most significant digit) reflects former limit triangle A line current effective value.Current effective value identification code is mainly used in the relative size reflecting each line current effective value, to diagnose transformer open circuit fault.If certain cover winding current effective value is 0, on corresponding position, line current identification code is 0, and other line current effective value of this cover winding is identical, and corresponding positions identification code is 1; If certain cover winding current effective value is not 0, then this cover winding three line current effective value identification codes are all 2.

4. voltage effective value identification code is 3 decimal numbers, 0th (lowest order) reflects former limit triangle C line voltage effective value, 1st reflection former limit triangle B line voltage effective value, the 2nd (most significant digit) reflects former limit triangle A line voltage effective value.Voltage effective value identification code is mainly used in distinguishing the single-phase outside open circuit of former limit delta windings and former limit delta windings two-phase internal break.There are two kinds of situations in former sideline voltage effective value, the wired voltage effective value of institute is identical, and voltage effective value identification code every is all 1; A certain line voltage effective value is 2 times of all the other line voltage effective values, then this line voltage effective value identification code is 2, and all the other positions are 1.

5. excess current identification code is 9 bits, 0th (lowest order) reflects secondary star c2 line current overcurrent condition, 1st reflection secondary star b2 line current overcurrent condition, 2nd reflection secondary star a2 line current overcurrent condition, 3rd reflection secondary triangle c1 line current overcurrent condition, 4th reflection secondary triangle b1 line current overcurrent condition, 5th reflection secondary triangle a1 line current overcurrent condition, 6th reflection former limit triangle C line current overcurrent condition, 7th reflection former limit triangle B line current overcurrent condition, 8th (most significant digit) reflects former limit triangle A line current overcurrent condition.Excess current identification code mainly for detection of each line current whether overcurrent, to diagnose transformer external short circuit fault.If certain line current exists excess current, then corresponding positions excess current identification code is 1, otherwise is 0.

6. current-unbalance degree identification code is 6 decimal numbers, 0th (lowest order) reflects the unbalanced degree of secondary star c2 line current, 1st the unbalanced degree of reflection secondary star b2 line current, 2nd the unbalanced degree of reflection secondary star a2 line current, 3rd the unbalanced degree of reflection secondary triangle c1 line current, 4th the unbalanced degree of reflection secondary triangle b1 line current, the 5th the unbalanced degree of reflection secondary triangle a1 line current.Current-unbalance degree identification code is used for diagnosing the unconspicuous fault of current characteristic (as: there is not overcurrent, there is not electric current is 0).For certain a set of winding, be greater than the mean value of this cover winding wire current effective value as crossed a certain line current, then current-unbalance degree identification code gets 2; If a certain line current equals the mean value of this cover winding wire current effective value, current-unbalance degree identification code gets 1; If a certain line current is less than the mean value of this cover winding wire current effective value, current-unbalance degree identification code gets 0.

7. secondary harmonic brake code is 1 bit.Former limit has at least a line current second harmonic to exceed setting valve, and this position gets 1; When only having former sideline electric current second harmonic all not exceed setting valve, this just gets 0.Whether its reflection transformer exists excitation surge current.When transformer produces excitation surge current, transformer differential protection meeting malfunction, secondary harmonic brake code is just used to realize transformer differential protection braking, prevents malfunction.

Step 3, transformer fault detect and comprise following steps: parameter detecting algorithm, fault protection algorithms and fault diagnosis algorithm.

(1), parameter detecting algorithm is as follows:

1, current effective value computing formula:

2, voltage effective value computing formula:

3, active power calculates formula: $P_A=\sqrt{\frac{\underset{0}{\overset{n}{\mathrm{\Σ}}}((u_{\mathrm{AB}}-u_{\mathrm{CA}})\×i_A)}{3\×n}}$

$P_B=\sqrt{\frac{\underset{0}{\overset{n}{\mathrm{\Σ}}}((u_{\mathrm{BC}}-u_{\mathrm{AB}})\×i_B)}{3\×n}}$

$P_C=\sqrt{\frac{\underset{0}{\overset{n}{\mathrm{\Σ}}}((u_{\mathrm{AC}}-u_{\mathrm{BC}})\×i_C)}{3\×n}}$

5, applied power calculates formula: $S_A=\frac{\sqrt{\underset{0}{\overset{n}{\mathrm{\Σ}}}{(u_{\mathrm{AB}}-u_{\mathrm{CA}})}^2}\×\sqrt{\underset{0}{\overset{n}{\mathrm{\Σ}}}{i}_A^2}}{3\×n}$

$S_B=\frac{\sqrt{\underset{0}{\overset{n}{\mathrm{\Σ}}}{(u_{\mathrm{BC}}-u_{\mathrm{AB}})}^2}\×\sqrt{\underset{0}{\overset{n}{\mathrm{\Σ}}}{i}_B^2}}{3\×n}$

$S_C=\frac{\sqrt{\underset{0}{\overset{n}{\mathrm{\Σ}}}{(u_{\mathrm{CA}}-u_{\mathrm{BC}})}^2}\×\sqrt{\underset{0}{\overset{n}{\mathrm{\Σ}}}{i}_C^2}}{3\×n}$

6, power factor calculates formula: W=P/S

7, power-factor angle computing formula: A=acos (W)

8, Fast Fourier Transform (FFT): Fast Fourier Transform (FFT) should use private library function to operate, and using method is as follows: the object fft of a structure CFFT32 type, and Fast Fourier Transform (FFT) parameter is set, as converted the FFT_N that counts; Original signal to be transformed is given the structure fft_ipcb [2*FFT_N] of fft object, wherein fft_ipcb [2*i] real part that is original signal value, the imaginary part that fft_ipcb [2*i+1] is original signal value, 0≤i≤FFT_N, then carries out inverted order computing to fft_ipcb [2*FFT_N] structure; Window function is added to fft object, such as HANNING window; Calculate fft object; Calculate each harmonic amplitude.The result of Fast Fourier Transform (FFT) is as follows: each harmonic component is stored in fft_ipcb [2*FFT_N] structure, and wherein real part is stored on fft_ipcb [2*i], and imaginary part is stored on fft_ipcb [2*i+1], 0≤i≤FFT_N; The square value of each harmonic amplitude is stored in fft_mag [FFT_N] structure; Fft_ipcb [0] and fft_mag [0] is DC component; Fft_ipcb [2*X] is first-harmonic real part, and fft_ipcb [2*X+1] is first-harmonic imaginary part, the square value that fft_mag [X] is fundamental voltage amplitude, wherein X=(signal frequency × FFT_N)/sample frequency; Fft_ipcb [N*2*X] is N subharmonic real part, and fft_ipcb [N*2*X+1] is N subharmonic imaginary part, and the square value that fft_mag [N*X] is N subharmonic amplitude, wherein N is overtone order.

9, fundamental signal phase calculation formula: θ=atan (fft_ipcb [2*X+1], fft_ipcb [2*X])

(2) fault protection algorithms is as follows:

1, two sections of ratio formula longitudinal difference protections calculate

A phase longitudinal difference protection action current computing formula:

B phase longitudinal difference protection action current computing formula:

C phase longitudinal difference protection action current computing formula:

A phase longitudinal difference protection stalling current computing formula:

B phase longitudinal difference protection stalling current computing formula:

C phase longitudinal difference protection stalling current computing formula:

A phase longitudinal difference protection action current effective value computing formula:

B phase longitudinal difference protection action current effective value computing formula:

C phase longitudinal difference protection action current effective value computing formula:

A phase longitudinal difference protection stalling current effective value computing formula:

B phase longitudinal difference protection stalling current effective value computing formula:

C phase longitudinal difference protection stalling current effective value computing formula:

A phase longitudinal difference protection operating criterion computing formula:

$\left\{\begin{array}{cc}{I}_{\mathrm{act}\_A\_\mathrm{rms}}\≥I_{\mathrm{act}\_\min }& (I_{\mathrm{res}\_A\_\mathrm{rms}}\≤I_{\mathrm{res}\_\min })\\ I_{\mathrm{act}\_A\_\mathrm{rms}}\≥I_{\mathrm{act}\_\min }+m(I_{\mathrm{res}\_A\_\mathrm{rms}}-I_{\mathrm{res}\_\min })& (I_{\mathrm{res}\_A\_\mathrm{rms}}>I_{\mathrm{res}\_\min })\end{array}\right.$

B phase longitudinal difference protection operating criterion computing formula:

$\left\{\begin{array}{cc}{I}_{\mathrm{act}\_B\_\mathrm{rms}}\≥I_{\mathrm{act}\_\min }& (I_{\mathrm{res}\_B\_\mathrm{rms}}\≤I_{\mathrm{res}\_\min })\\ I_{\mathrm{act}\_B\_\mathrm{rms}}\≥I_{\mathrm{act}\_\min }+m(I_{\mathrm{res}\_B\_\mathrm{rms}}-I_{\mathrm{res}\_\min })& (I_{\mathrm{res}\_B\_\mathrm{rms}}>I_{\mathrm{res}\_\min })\end{array}\right.$

C phase longitudinal difference protection operating criterion computing formula:

$\left\{\begin{array}{cc}{I}_{\mathrm{act}\_C\_\mathrm{rms}}\≥I_{\mathrm{act}\_\min }& (I_{\mathrm{res}\_C\_\mathrm{rms}}\≤I_{\mathrm{res}\_\min })\\ I_{\mathrm{act}\_C\_\mathrm{rms}}\≥I_{\mathrm{act}\_\min }+m(I_{\mathrm{res}\_C\_\mathrm{rms}}-I_{\mathrm{res}\_\min })& (I_{\mathrm{res}\_C\_\mathrm{rms}}>I_{\mathrm{res}\_\min })\end{array}\right.$

2, zero-sequence component protection calculation

Residual voltage computing formula: $V_{\mathrm{zero}}=\frac{1}{3}(v_A+v_B+v_C)$

Zero-sequence current computing formula: $I_{\mathrm{zero}}=\frac{1}{3}(i_A+i_B+i_C)$

Residual voltage effective value computing formula:

Zero-sequence current effective value computing formula:

Residual voltage setting valve computing formula: $V_{\mathrm{zero}\_\mathrm{set}}=\frac{1}{3}(V_{A\_\mathrm{rms}}+V_{B\_\mathrm{rms}}+V_{C\_\mathrm{rms}})\×K_{\mathrm{set}}$

Zero-sequence current setting valve computing formula: $I_{\mathrm{zero}\_\mathrm{set}}=\frac{1}{3}(I_{A\_\mathrm{rms}}+I_{B\_\mathrm{rms}}+I_{C\_\mathrm{rms}})\×K_{\mathrm{set}}$

3, overload protection computing formula: S _set=S _rating× K _set

4, calculation of over current protection formula: I _set=I _rating× K _set

Fault diagnosis adopts transformer electrical quantity knowledge base method, and the calculating of fault signature identification code is comprised in parameter detecting algorithm and fault protection algorithms, and its algorithm is described below with logical language:

If ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (excess current identification code=000000000| excess current identification code=111111111) & (current-unbalance degree identification code=111111))

{ transformer state=normally work }

Elesif ((longitudinal difference protection identification code=1) & (secondary harmonic brake code=1))

{ transformer state=excitation surge current }

Elesif ((longitudinal difference protection identification code=1) & (zero-sequence current protection identification code=100) & (secondary harmonic brake code=0))

{ transformer state=former limit D winding turns ground short circuit }

Elesif ((longitudinal difference protection identification code=1) & (zero-sequence current protection identification code=010) & (secondary harmonic brake code=0))

{ transformer state=secondary d winding turns ground short circuit }

Elesif ((longitudinal difference protection identification code=1) & (zero-sequence current protection identification code=001) & (secondary harmonic brake code=0))

{ transformer state=secondary y winding turns ground short circuit }

Elesif ((longitudinal difference protection identification code=1) & (zero-sequence current protection identification code=000) & (secondary harmonic brake code=0))

{ transformer state=turn-to-turn short circuit }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=011011222) & (voltage effective value identification code=121))

{ the single-phase outside open circuit of transformer state=A phase }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=101101222) & (voltage effective value identification code=112))

{ the single-phase outside open circuit of transformer state=B phase }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=110110222) & (voltage effective value identification code=211))

{ the single-phase outside open circuit of transformer state=C phase }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222011222))

{ the single-phase outside open circuit of transformer state=a1 phase or c1, a1 phase two-phase internal break }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222101222))

{ the single-phase outside open circuit of transformer state=b1 phase or a1, b1 phase two-phase internal break }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222110222))

{ the single-phase outside open circuit of transformer state=c1 phase or b1, c1 phase two-phase internal break }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222011))

{ the single-phase outside open circuit of transformer state=a2 phase or internal break }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222101))

{ the single-phase outside open circuit of transformer state=b2 phase or internal break }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222110))

{ the single-phase outside open circuit of transformer state=c2 phase or internal break }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222000222))

{ transformer state=d0 winding at least two-phase open circuit }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222000))

{ transformer state=y11 winding at least two-phase open circuit }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (current-unbalance degree identification code=202102))

{ transformer state=single-phase internal break of A phase }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (current-unbalance degree identification code=220210))

{ transformer state=single-phase internal break of B phase }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (current-unbalance degree identification code=022021))

{ transformer state=single-phase internal break of C phase }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (current-unbalance degree identification code=201111))

{ transformer state=single-phase internal break of a1 phase }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (current-unbalance degree identification code=120111))

{ transformer state=single-phase internal break of b1 phase }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (current-unbalance degree identification code=012111))

{ transformer state=single-phase internal break of c1 phase }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=101101222) & (voltage effective value identification code=111))

{ transformer state=A, B phase two-phase internal break }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=110110222) & (voltage effective value identification code=111))

{ transformer state=B, C phase two-phase internal break }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=011011222) & (voltage effective value identification code=111))

{ transformer state=C, A phase two-phase internal break }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (excess current identification code=100111000))

{ transformer state=a1 phase one-phase short-circuit current }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (excess current identification code=010111000))

{ transformer state=b1 phase one-phase short-circuit current }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (excess current identification code=001111000))

{ transformer state=c1 phase one-phase short-circuit current }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (excess current identification code=110000111))

{ transformer state=a2 phase one-phase short-circuit current }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (excess current identification code=011000111))

{ transformer state=b2 phase one-phase short-circuit current }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (excess current identification code=101000111))

{ transformer state=c2 phase one-phase short-circuit current }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (excess current identification code code=110110000))

{ the outside phase fault of transformer state=a1, b1 }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (excess current identification code=011011000))

{ the outside phase fault of transformer state=b1, c1 }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (excess current identification code=101101000))

{ the outside phase fault of transformer state=c1, a1 }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (excess current identification code=111000110))

{ the outside phase fault of transformer state=a2, b2 }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (excess current identification code=111000011))

{ the outside phase fault of transformer state=b2, c2 }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (excess current identification code=111000101))

{ the outside phase fault of transformer state=c2, a2 }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (excess current identification code=000000000) & (current-unbalance degree identification code=202220))

{ the outside phase fault of transformer state=a1, a2 }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (excess current identification code=110110110))

{ the outside phase fault of transformer state=a1, b2 }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (excess current identification code=101101111))

{ the outside phase fault of transformer state=a1, c2 }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (excess current identification code=110110111))

{ the outside phase fault of transformer state=b1, a2 }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (excess current identification code=000000000) & (current-unbalance degree identification code=220022))

{ the outside phase fault of transformer state=b1, b2 }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (excess current identification code=011011011))

{ the outside phase fault of transformer state=b1, c2 }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (excess current identification code=101101101))

{ the outside phase fault of transformer state=c1, a2 }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (excess current identification code=011011111))

{ the outside phase fault of transformer state=c1, b2 }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (excess current identification code=000000000) & (current-unbalance degree identification code=022202))

{ the outside phase fault of transformer state=c1, c2 }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (excess current identification code=111111000))

{ transformer state=a1, b1, c1 phase three relative ground circuit }

Elesif ((longitudinal difference protection identification code=0) & (current effective value identification code=222222222) & (excess current identification code=111000111))

{ transformer state=a2, b2, c2 phase three relative ground circuit }

Specific embodiment described herein is only to the explanation for example of the present invention's spirit.Those skilled in the art can make various amendment or supplement or adopt similar mode to substitute to described specific embodiment, but can't depart from spirit of the present invention or surmount the scope that appended claims defines.

Claims (2)

1. a transformer fault detection method, is characterized in that, comprises the following steps:

Step 1, set up transformer fault model: for the transformer type that will detect, analyzed the type of the relay protection that the change of transformer each phase winding line voltage waveform and line current waveform before and after various fault and this fault trigger by theoretical analysis or Softwares of System Simulation;

Step 2, set up transformer electrical quantity knowledge base: the type of the relay protection that change and this fault of transformer each phase winding line voltage waveform and line current waveform before and after various fault trigger is analyzed, system of selection is simple, the fault signature of successful, is encoded into fault signature identification code and is cured in transformer electrical quantity knowledge base and goes;

Wherein, transformer fault storehouse comprises following 7 contents: longitudinal difference protection identification code, zero-sequence current protection identification code, current effective value identification code, voltage effective value identification code, excess current identification code, current-unbalance degree identification code and secondary harmonic brake code; Specific as follows:

Identification code one. longitudinal difference protection identification code is 1 bit, this position reflection transformer differential protection state; Transformer has a phase generation Current Differential Protection at least, and this position gets 1; Only have transformer current longitudinal difference protection not to occur, this just gets 0;

Identification code two. zero-sequence current protection identification code is 3 bits, the 0th reflection star secondary zero-sequence current protection state, the 1st reflection triangle secondary zero-sequence current protection state, the 2nd reflection former limit zero-sequence current protection state; If during certain limit winding generation zero-sequence current protection, the identification code on the corresponding position of this limit winding is 1; If when zero-sequence current protection does not occur certain limit winding, the identification code on the corresponding position of this limit winding is 0;

Identification code three. current effective value identification code is 9 decimal numbers, 0th reflection secondary star c2 line current effective value, 1st reflection secondary star b2 line current effective value, 2nd reflection secondary star a2 line current effective value, 3rd reflection secondary triangle c1 line current effective value, 4th reflection secondary triangle b1 line current effective value, 5th reflection secondary triangle a1 line current effective value, 6th reflection former limit triangle C line current effective value, 7th reflection former limit triangle B line current effective value, 8th reflection former limit triangle A line current effective value, current effective value identification code is mainly used in the relative size reflecting each line current effective value, to diagnose transformer open circuit fault, if certain cover winding current effective value is 0, on corresponding position, line current identification code is 0, and other line current effective value of this cover winding is identical, and corresponding positions identification code is 1, if certain cover winding current effective value is not 0, then this cover winding three line current effective value identification codes are all 2,

Identification code four. voltage effective value identification code is 3 decimal numbers, 0th reflection former limit triangle C line voltage effective value, 1st reflection former limit triangle B line voltage effective value, the 2nd (most significant digit) reflects former limit triangle A line voltage effective value; Voltage effective value identification code is mainly used in distinguishing the single-phase outside open circuit of former limit delta windings and former limit delta windings two-phase internal break; There are two kinds of situations in former sideline voltage effective value, the wired voltage effective value of institute is identical, and voltage effective value identification code every is all 1; A certain line voltage effective value is 2 times of all the other line voltage effective values, then this line voltage effective value identification code is 2, and all the other positions are 1;

Identification code five. excess current identification code is 9 bits, 0th reflection secondary star c2 line current overcurrent condition, 1st reflection secondary star b2 line current overcurrent condition, 2nd reflection secondary star a2 line current overcurrent condition, 3rd reflection secondary triangle c1 line current overcurrent condition, 4th reflection secondary triangle b1 line current overcurrent condition, 5th reflection secondary triangle a1 line current overcurrent condition, 6th reflection former limit triangle C line current overcurrent condition, 7th reflection former limit triangle B line current overcurrent condition, 8th reflection former limit triangle A line current overcurrent condition, excess current identification code mainly for detection of each line current whether overcurrent, to diagnose transformer external short circuit fault, if certain line current exists excess current, then corresponding positions excess current identification code is 1, otherwise is 0,

Identification code six. current-unbalance degree identification code is 6 decimal numbers, 0th the unbalanced degree of reflection secondary star c2 line current, 1st the unbalanced degree of reflection secondary star b2 line current, 2nd the unbalanced degree of reflection secondary star a2 line current, 3rd the unbalanced degree of reflection secondary triangle c1 line current, 4th the unbalanced degree of reflection secondary triangle b1 line current, the 5th the unbalanced degree of reflection secondary triangle a1 line current; Current-unbalance degree identification code is used for diagnosing the unconspicuous fault of current characteristic; For certain a set of winding, be greater than the mean value of this cover winding wire current effective value as crossed a certain line current, then current-unbalance degree identification code gets 2; If a certain line current equals the mean value of this cover winding wire current effective value, current-unbalance degree identification code gets 1; If a certain line current is less than the mean value of this cover winding wire current effective value, current-unbalance degree identification code gets 0;

Identification code seven. secondary harmonic brake code is 1 bit; Former limit has at least a line current second harmonic to exceed setting valve, and this position gets 1; When only having former sideline electric current second harmonic all not exceed setting valve, this just gets 0; Whether its reflection transformer exists excitation surge current; When transformer produces excitation surge current, transformer differential protection meeting malfunction, secondary harmonic brake code is just used to realize transformer differential protection braking, prevents malfunction;

Step 3, gather original signal, the transformer electrical quantity knowledge base that the transformer fault model set up based on step 1 and step 2 are set up carries out the detection of transformer fault type and position of failure point: calculate outlet voltage effective value, line current effective value, line voltage phase angle, line current phasing degree, active power, reactive power, applied power, power factor, power-factor angle etc. by parameter detecting detection algorithm; Then calculating two sections of ratio formula longitudinal difference protections, zero-sequence component protection, overload protection, calculation of over current protection by fault protection algorithms, preventing protective relaying maloperation from doing by calculating excitation surge current simultaneously; Following fault is detected: outside open circuit fault, internal break fault, shorted to earth fault, all over the ground short trouble, shorted-turn fault, outside phase fault, inner phase fault, overload fault, over current fault finally by looking into transformer fault feature database.

2. a kind of transformer fault detection method according to claim 1, it is characterized in that, described step 1 is selective system simulation software MATLAB for the transformer fault Developing Transformer fault model of such as Types Below, and selected transformer fault type comprises: outside open circuit fault, internal break fault, shorted to earth fault, all over the ground short trouble, shorted-turn fault, outside phase fault and inner phase fault; Transformer fault model downloads in dSpace semi-physical emulation platform to produce analogue transformer line pressure-wire current waveform for exploitation, debugging and checking by debugging computer.