CN104237705A - Multi-information fusion online monitoring device and diagnostic method for windings of power transformers - Google Patents

Abstract

The invention discloses a multi-information fusion online monitoring device and a diagnostic method for windings of power transformers. The multi-information fusion online monitoring device comprises a voltage sensor, a current sensor, a vibration acceleration sensor, a phase shift amplifier circuit, a signal conditioning circuit, an A/D (analog/digital) conversion control circuit, a DSP (digital signal processor), a dual-port RAM (random access memory) and an MCU (microprogrammed control unit). The diagnostic method includes acquiring three-phase primary-side voltage signals, three-phase secondary-side voltage signals, three-phase primary-side current signals and three-phase mechanical vibration signals of the power transformers; processing the signals; performing FFT (fast Fourier transform) decomposition on various phases of mechanical vibration digital signals to obtain amplitude values of fundamental frequencies of various phases of mechanical vibration signals; building online short-circuit reactance models; computing short-circuit reactance of various phases of windings of the power transformers; diagnosing mechanical vibration faults of the transformers by the aid of fitting results of the short-circuit reactance of the various phases of windings, effective current values and the amplitude values of the fundamental frequencies of the mechanical vibration signals corresponding to the effective current values.

Description

The Winding in Power Transformer on-Line Monitor Device of Multi-information acquisition and diagnostic method

Technical field

The invention belongs to diagnosing fault of power transformer technical field, be specifically related to Winding in Power Transformer on-Line Monitor Device and the diagnostic method of Multi-information acquisition.

Background technology

Power transformer is one of power transmission and transforming equipment important in electric system, connects multiple electric pressure, is in hinge status in electrical network.Its safe reliability run directly affects the security of operation of electrical network, improves the operational reliability of power transformer, is of great significance the safe and reliable operation tool of whole electrical network.

Power Transformer Faults comprises mechanical fault, insulation fault, overheating fault etc., and most insulation fault is caused by mechanical fault.In statistical report about large-scale power transformer fault, nearly more than 60% belongs to winding internal mechanical fault, drawn by statistical study and the chief component that the mechanical fault that causes is transformer fault such as to loosen because winding deformation, winding compress, therefore in order to ensure the safe reliability that transformer runs, the research carrying out Transformer Winding running status seems particularly important

The winding failure diagnostic method of current employing is mainly frequency response analysis and short-circuit reactance test method(s), and two kinds of methods all require transformer rear offline inspection out of service, can not Real-Time Monitoring transformer run situation.Although vibration analysis method can carry out on-line monitoring to transformer, the method requires high to surrounding environment, and the factors such as transformer operating condition and environment temperature all can produce a very large impact the vibration measurement result of transformer.Comprehensive existing several diagnostic method can find out that current power Transformer Winding on-line fault diagnosis just utilizes single or certain several test parameters to draw diagnostic result, the diagnostic signal simplification existed, cannot the problem of comprehensive monitoring Winding in Power Transformer operation conditions.

Summary of the invention

According to the deficiencies in the prior art, the present invention proposes Winding in Power Transformer on-Line Monitor Device and the diagnostic method of Multi-information acquisition.

Technical scheme of the present invention is:

The Winding in Power Transformer on-Line Monitor Device of Multi-information acquisition, comprises voltage sensor, current sensor, vibration acceleration sensor, phase shift amplifying circuit, signal conditioning circuit, A/D conversion control circuit, DSP, dual port RAM and MCU (micro-control unit).

The output terminal of voltage sensor, the output terminal of current sensor are connected the input end of phase shift amplifying circuit respectively with the output terminal of vibration acceleration sensor, the input end of the output terminal connection signal modulate circuit of phase shift amplifying circuit, the output terminal of signal conditioning circuit connects the input end of A/D conversion control circuit, the output terminal of A/D conversion control circuit connects the input end of DSP, and DSP and MCU is connected by dual port RAM.

Current sensor and voltage sensor are connected Current Transformer Secondary side, the voltage transformer secondary side of transformer station respectively.

Vibration acceleration sensor is installed on the correspondence position of power transformer three-phase windings at fuel tank sidewall.

Described phase shift amplifying circuit is used for the signal of collection to carry out decoupling and filtering process, comprise operational amplifier, first electric capacity, second electric capacity, 3rd electric capacity, feedback resistance, first slide rheostat and the second slide rheostat, the diode of input end two reversal connections in parallel of operational amplifier, the output terminal of operational amplifier connects one end of the 3rd electric capacity, the other end ground connection of the 3rd electric capacity, the input end of operational amplifier also connects one end of the first slide rheostat, the other end of the first slide rheostat connects one end of feedback resistance, the output terminal of the other end concatenation operation amplifier of feedback resistance, the input end of operational amplifier also connects one end of the second slide rheostat, the other end of the second slide rheostat connects one end of the first electric capacity, the output terminal of the other end concatenation operation amplifier of the first electric capacity, the input end of operational amplifier also connects one end of the second electric capacity, the output terminal of the other end concatenation operation amplifier of the second electric capacity.

Described signal conditioning circuit is used for converting simulating signal to fully differential input signal, comprise the first operational amplifier, second operational amplifier, first resistance, second resistance, 3rd resistance, 4th resistance, 5th resistance and the 6th resistance, the negative input end of the first operational amplifier connects one end of the 3rd resistance, the other end ground connection of the 3rd resistance, the positive input terminal of the first operational amplifier connects one end of the 4th resistance, the negative input end of the first operational amplifier also connects one end of the first resistance, the other end of the first resistance connects the output terminal of the first operational amplifier, the positive input terminal of the first operational amplifier also connects one end of the second resistance, the other end of the second resistance connects the output terminal of the second operational amplifier, the negative input end of the second operational amplifier and output terminal short circuit, the output terminal of the first operational amplifier connects one end of the 5th resistance, the other end of the 5th resistance connects the input end of A/D conversion control circuit, the output terminal of the second operational amplifier also connects one end of the 6th resistance, the other end of the 6th resistance connects the input end of A/D conversion control circuit, the positive input terminal of the second operational amplifier connects the input end of A/D conversion control circuit.

Described A/D conversion control circuit comprises two A/D conversion chips, and the cascade of two A/D conversion chips.

Adopt the Winding in Power Transformer diagnostic method of the Winding in Power Transformer on-Line Monitor Device of Multi-information acquisition, comprise the following steps:

Step 1: voltage sensor gathers three-phase primary side voltage signal and the three-phase secondary side voltage signal of power transformer by the voltage transformer secondary side of transformer station, current sensor gathers the three-phase primary side current signal of power transformer by the Current Transformer Secondary side of transformer station, and vibration transducer gathers the three-phase mechanical vibration signal of power transformer.

Step 2: each phase primary side voltage signal of power transformer, each phase secondary side voltage signal and each phase primary side current signal and each mechanical kilowatt vibration signal of power transformer tank are carried out decoupling and filtering process by phase shift amplifying circuit.

Step 3: each phase primary side voltage signal after decoupling and filtering process, each phase secondary side voltage signal, each phase primary side current signal and each mechanical kilowatt vibration signal are carried out amplitude limiting processing by signal conditioning circuit, make it meet the input range of A/D conversion control circuit.

Each phase primary side voltage signal after amplitude limiting processing, each phase secondary side voltage signal, each phase primary side current signal and each mechanical kilowatt vibration signal are carried out analog to digital conversion by step 4:A/D conversion control circuit, obtain each phase primary side voltage digital signal, each phase secondary side voltage digital signal, each phase primary side current digital signal and each mechanical kilowatt vibration digital signal.

Step 5:DSP adopts short-circuit reactance method and mechanical vibration method to process each phase primary side voltage digital signal, each phase secondary side voltage digital signal, each phase primary side current digital signal and each mechanical kilowatt vibration digital signal, carries out mechanical vibration fault diagnosis to each phase winding of power transformer.

Step 5.1: calculate the phasor of each phase primary side voltage digital signal, phase angle and effective value, each phase secondary side voltage digital signal phasor, phase angle and effective value, each phase primary side current digital signal phasor, phase angle and effective value respectively.

Step 5.2: each mechanical kilowatt vibration digital signal is decomposed by FFT and carries out frequency domain character extraction, obtain the fundamental frequency amplitude of each mechanical kilowatt vibration signal, using the mechanical vibration eigenwert of the fundamental frequency amplitude of each mechanical kilowatt vibration signal as each phase winding of power transformer.

Step 5.3: the online short-circuit reactance model setting up power transformer, using the input as the online short-circuit reactance model of power transformer of each phase primary side voltage digital signal, each phase secondary side voltage digital signal and each primary side current digital signal, calculate the short-circuit reactance of each phase winding of power transformer, using the electric characteristic value of the short-circuit reactance of each for power transformer phase winding as each phase winding of power transformer.

Step 5.4: the reactance change rate calculating the short-circuit reactance of each phase winding of power transformer and the short-circuit reactance of each phase winding of the trouble-free power transformer of history.

Step 5.5: the upper limit threshold of setting reactance change rate and the lower threshold of reactance change rate, if the reactance change rate of the Winding in Power Transformer obtained is greater than reactance change rate upper limit threshold, then judge that this phase winding of power transformer exists mechanical vibration fault, perform step 6, if the reactance change rate of the Winding in Power Transformer obtained is greater than reactance change rate lower threshold and be less than reactance change rate upper limit threshold, then perform step 5.6, if the reactance change rate of the Winding in Power Transformer obtained is less than reactance change rate lower threshold, then judge that this phase winding of power transformer is normal, perform step 6.

Step 5.6: the fundamental frequency amplitude of mechanical oscillation signal corresponding with it for each phase current effective value of Winding in Power Transformer is carried out matching, the fundamental frequency amplitude fitting result of mechanical oscillation signal corresponding with it for each phase current effective value obtained is mated with the fundamental frequency amplitude fitting result of its corresponding mechanical oscillation signal with this phase current effective value of the trouble-free Winding in Power Transformer of history, judge error that matching result exists whether in error allowed band, if, then judge that this phase winding of power transformer is normal, otherwise, then judge that this phase winding of power transformer exists mechanical vibration fault.

The result of determination of each phase winding of power transformer is shown by display screen by step 6:MUC, and result of determination comprises: winding is normal, A phase winding mechanical vibration fault, B phase winding mechanical vibration fault, C phase winding mechanical vibration fault and three-phase windings mechanical vibration fault.

The invention has the beneficial effects as follows: the present invention establishes the Winding in Power Transformer on-Line Monitor Device of Multi-information acquisition, gather each phase winding electric current, each phase winding voltage and each phase winding mechanical vibration parameter integrated information, and by Transformer Winding normal and fault different conditions attribute testing, set up the two information combination harvester of transformer winding state based on reactance signal and vibration signal; By the reactance change threshold value of online short-circuit reactance method to the error analysis of electric current, voltage sensor further explication, fft algorithm is applied in winding mechanical vibration method simultaneously and extracts fundamental vibration change, improve the intelligent and accuracy of Transformer Winding diagnostic method further; The online multi information method for diagnosing status of the Winding in Power Transformer that electrical specification and mechanical property merge mutually, short-circuit reactance method and mechanical vibration method are combined, solves diagnostic signal simplification that the diagnosis of current transformer winding fault exists and cannot the problem such as real time on-line monitoring winding operation conditions.

Accompanying drawing explanation

Fig. 1 is the structural drawing of the Winding in Power Transformer on-Line Monitor Device of Multi-information acquisition in present embodiment;

Fig. 2 is the circuit diagram of phase shift amplifying circuit in the Winding in Power Transformer on-Line Monitor Device of Multi-information acquisition in present embodiment;

Fig. 3 is the circuit connection diagram of signal conditioning circuit, A/D conversion control circuit and DSP in the Winding in Power Transformer on-Line Monitor Device of Multi-information acquisition in present embodiment;

Fig. 4 is the circuit connection diagram of DSP, dual port RAM, MCU and OLED liquid crystal display circuit in the Winding in Power Transformer on-Line Monitor Device of Multi-information acquisition in present embodiment;

Fig. 5 is the process flow diagram of the Winding in Power Transformer diagnostic method of Multi-information acquisition in present embodiment;

Fig. 6 is equivalent circuit of transformer in the Winding in Power Transformer on-Line Monitor Device of Multi-information acquisition in present embodiment.

Embodiment

Below in conjunction with accompanying drawing to specific embodiment of the invention detailed description in addition.

The Winding in Power Transformer on-Line Monitor Device of Multi-information acquisition, as shown in Figure 1, comprises voltage sensor, current sensor, vibration acceleration sensor, phase shift amplifying circuit, signal conditioning circuit, A/D conversion control circuit, DSP, dual port RAM and MCU.

The output terminal of voltage sensor, the output terminal of current sensor are connected the input end of phase shift amplifying circuit respectively with the output terminal of vibration acceleration sensor, the input end of the output terminal connection signal modulate circuit of phase shift amplifying circuit, the output terminal of signal conditioning circuit connects the input end of A/D conversion control circuit, the output terminal of A/D conversion control circuit connects the input end of DSP, and DSP and MCU is connected by dual port RAM.

Current sensor and voltage sensor are connected Current Transformer Secondary side, the voltage transformer secondary side of transformer station respectively.

In present embodiment, select model to be the current sensor of SCT254FK, select the model of Xing Ge company to be the voltage sensor of SPT204A.

Vibration acceleration sensor is installed on the correspondence position of power transformer three-phase windings at fuel tank sidewall.

In present embodiment, Lanace company model is selected to be the vibration acceleration sensor of LC0154.

As shown in Figure 2, phase shift amplifying circuit is used for the signal of collection to carry out decoupling and filtering process, comprises operational amplifier, the first electric capacity, the second electric capacity C ₂, the 3rd electric capacity C ₃, feedback resistance R, the first slide rheostat r and the second slide rheostat r ', the diode of input end two reversal connections in parallel of operational amplifier, the output terminal of operational amplifier connects the 3rd electric capacity C ₃one end, the 3rd electric capacity C ₃other end ground connection, the input end of operational amplifier also connects one end of the first slide rheostat r, the other end of the first slide rheostat r connects one end of feedback resistance R, the output terminal of the other end concatenation operation amplifier of feedback resistance R, the input end of operational amplifier also connects one end of the second slide rheostat r ', and the other end of the second slide rheostat r ' connects the first electric capacity C ₁one end, the first electric capacity C ₁the output terminal of other end concatenation operation amplifier, the input end of operational amplifier also connects the second electric capacity C ₂one end, the second electric capacity C ₂the output terminal of other end concatenation operation amplifier.Electric capacity C ₂and C ₃select the small capacitances of 400 to 1000pF, be used for decoupling and filtering.Operational amplifier precision uses OP07 series, can be easier to reach higher precision and good stability.

As shown in Figure 3, signal conditioning circuit is used for converting simulating signal to fully differential input signal, comprises the first operational amplifier, the second operational amplifier, the first resistance R ₁, the second resistance R ₂, the 3rd resistance R ₃, the 4th resistance R ₄, the 5th resistance R ₅with the 6th resistance R ₆, the negative input end of the first operational amplifier connects the 3rd resistance R ₃one end, the 3rd resistance R ₃other end ground connection, the positive input terminal of the first operational amplifier connects the 4th resistance R ₄one end, the 4th resistance R ₄the other end connect bipolarity input end, the negative input end of the first operational amplifier also connects the first resistance R ₁one end, the first resistance R ₁the other end connect the output terminal of the first operational amplifier, the positive input terminal of the first operational amplifier also connects the second resistance R ₂one end, the second resistance R ₂the other end connect the output terminal of the second operational amplifier, the negative input end of the second operational amplifier and output terminal short circuit, the output terminal of the first operational amplifier connects the 5th resistance R ₅one end, the 5th resistance R ₅the other end connect the+IN end of A/D conversion control circuit, the output terminal of the second operational amplifier also connects the 6th resistance R ₆one end, the 6th resistance R ₆the other end connect the-IN end of A/D conversion control circuit, the positive input terminal of the second operational amplifier connects the+15V voltage end of A/D conversion control circuit.

The 3rd selected resistance R ₃for 4k Ω, the 4th resistance R ₄for 20k Ω, the 5th resistance R ₅for 1.2k Ω, the 6th resistance R ₆for 1.2k Ω,

First operational amplifier of signal conditioning circuit and the second operational amplifier adopt operation amplifier chip OPA227, and by resistance R ₁, R ₂make bipolarity input range for ± 2.5V, ± 5V, between ± 10V.

R ₁for 1k Ω R ₂during for 5k Ω, bipolarity is input as ± 10V, R ₁for 2k Ω R ₂during for 10k Ω, bipolarity is input as ± 5V, R ₁for 4k Ω R ₂during for 20k Ω, bipolarity is input as ± 2.5V.

A/D conversion control circuit comprises two A/D conversion chips, and the cascade of two A/D conversion chips, the model of the A/D conversion chip selected is ADS8365,

The data reading mode of ADS8364 mainly comprises first level address read mode, circulation read mode, FIFO read mode three kinds, selects first level address read mode in present embodiment.

Every sheet ADS8364 chip can realize the synchronous acquisition of six road signals, and two panels ADS8364 can realize the synchronous acquisition of 12 road signals, realizes the function of analog to digital conversion circuit.

The model of DSP is TMS320F28335.

A0, A1, A2, CS, RD, EOC, CLK end of ADS8365 connects XA0, XA1, XA2, CS, RE, XINT1, RWM5 end of TMS320F28335 respectively, D0 ~ D15 end of ADS8365 connects D0 ~ D15 end of TMS320F28335, BYTE and ADD of ADS8365 holds ground connection.

TMS320F28335DSP is by control A2, and the level of A1, A0 port is 001, and 010 ~ 101, control ALT-CH alternate channel CHA0, CHA1 ~ CHC1.When an eoc signal can be produced after Hexamermis spp data EOC to notify DSP EOC, after DSP detects this signal, read signal RD is set low, thus the signal after conversion is read in DSP successively, complete the analog to digital conversion of one group of data.

As shown in Figure 4, the circuit connection diagram of DSP, dual port RAM, MCU and OLED liquid crystal display circuit, R/W, DS, RD, READY end of TMS320F28335DSP connects R/W, CE of dual port RAM respectively _l, OE _l, BUSY _lend, the D0 ~ D7 of TMS320F28335DSP connects the D0 ~ D7 of dual port RAM _l, the A0 ~ A10 of TMS320F28335DSP connects the A0 ~ A10 of dual port RAM _l, the R/W of dual port RAM _r, CE _r, OE _r, BUSY _rend connects WR, ALE, RD, RDY end of MCU respectively, the D0 ~ D7 of TMS320F28335DSP _rend connects PB0 ~ PB7 end of dual port RAM, need to carry out bus extension to single-chip microcomputer during the connection of TMS320F28335DSP and dual port RAM, utilize the latch function of latch, by enable control, the mode of I/O mouth time-sharing multiplex is adopted to realize the read-write of address and data, the A0 ~ A7 of TMS320F28335DSP _rhold the PB0 ~ PB7 being connected dual port RAM by latch, the A8 ~ A10 of TMS320F28335DSP _rend connects PB8 ~ PB10 end of dual port RAM.

When DSP and MCU carries out exchanges data, for avoiding carrying out write operation to same address and producing conflict, in design, CY7C026 address space is divided into two regions, distribute to DSP and single-chip microcomputer use respectively, the two can only carry out write operation in the space distributing to oneself, in the other side region, carry out read operation, so just can avoid conflict generation, improves exchanges data reliability.

In present embodiment, select OLED liquid crystal display as human-computer interaction interface, select the VGY12864C display module of integrated SSD1305OLED driver, utilize OLED display module to improve the display capabilities on the spot of monitoring system, also extend its applied environment scope.MCU can show by connecting OLED liquid crystal display, PC8, PC9, PC10 end of MCU connects DC, WR, RD end of OLED respectively, PC0 ~ PC7 end of MCU connects DB0 ~ DB7 end of OLED, and the PC11 end of MCU connects the CS end of OLED, and the PC12 end of MCU connects the RST end of OLED.

In present embodiment, select chip and the element of technical grade, adopt reasonable PCB layout and manufacturing process, to cut off the interference of various electromagnetic coupled, ensure the height reliability of whole system as far as possible, take following measures:

(1) isolation and shield measure.Input, output circuit are effectively isolated by photo-coupler.During secondary circuit wiring by strong, weak electricity signal wire separately, realize isolation, avoiding between loop mutual induction and disturb impact mutually, signal wire and power lead separate by the wiring of printed circuit board (PCB), digital circuit separates with mimic channel, play good circuit isolation effect.

(2) process of power circuit.Between power supply positive and negative electrode, connect jumbo electric capacity, and have decoupling capacitance between all plug-in units and the VDD-to-VSS of chip, zero-power line takes the mode of floating, can reduce the distributed capacitance between power lead and casing as far as possible, avoid interference.

Adopt the Winding in Power Transformer diagnostic method of the Winding in Power Transformer on-Line Monitor Device of Multi-information acquisition, as shown in Figure 5, comprise the following steps:

Step 1: voltage sensor gathers three-phase primary side voltage signal and the three-phase secondary side voltage signal of power transformer by the voltage transformer secondary side of transformer station, current sensor gathers the three-phase primary side current signal of power transformer by the Current Transformer Secondary side of transformer station, and vibration transducer gathers the three-phase mechanical vibration signal of power transformer.

Step 2: each phase primary side voltage signal of power transformer, each phase secondary side voltage signal and each phase primary side current signal and each mechanical kilowatt vibration signal of power transformer tank are carried out decoupling and filtering process by phase shift amplifying circuit.

Step 3: each phase primary side voltage signal after decoupling and filtering process, each phase secondary side voltage signal, each phase primary side current signal and each mechanical kilowatt vibration signal are carried out amplitude limiting processing by signal conditioning circuit, make it meet the input range of A/D conversion control circuit.

Each phase primary side voltage signal after amplitude limiting processing, each phase secondary side voltage signal, each phase primary side current signal and each mechanical kilowatt vibration signal are carried out analog to digital conversion by step 4:A/D conversion control circuit, obtain each phase primary side voltage digital signal, each phase secondary side voltage digital signal, each phase primary side current digital signal and each mechanical kilowatt vibration digital signal.

Step 5:DSP adopts short-circuit reactance method and mechanical vibration method to process each phase primary side voltage digital signal, each phase secondary side voltage digital signal, each phase primary side current digital signal and each mechanical kilowatt vibration digital signal, carries out mechanical vibration fault diagnosis to each phase winding of power transformer.

Step 5.1: calculate the phasor of each phase primary side voltage digital signal, phase angle and effective value, each phase secondary side voltage digital signal phasor, phase angle and effective value, each phase primary side current digital signal phasor, phase angle and effective value respectively.

Step 5.2: each mechanical kilowatt vibration digital signal is decomposed by FFT and carries out frequency domain character extraction, obtain the fundamental frequency amplitude of each mechanical kilowatt vibration signal, using the mechanical vibration eigenwert of the fundamental frequency amplitude of each mechanical kilowatt vibration signal as each phase winding of power transformer.

Step 5.3: the online short-circuit reactance model setting up power transformer, using the input as the online short-circuit reactance model of power transformer of each phase primary side voltage digital signal, each phase secondary side voltage digital signal and each primary side current digital signal, calculate the short-circuit reactance of each phase winding of power transformer, using the electric characteristic value of the short-circuit reactance of each for power transformer phase winding as each phase winding of power transformer.

Equivalent circuit of transformer transformer as shown in Figure 6, Transformer Short Circuit Impedance is the equiva lent impedance of the inside transformer when loaded impedance is zero.The reactive component of short-circuit impedance, i.e. short-circuit reactance are exactly the leakage reactance of winding.Short-circuit reactance is relevant with physical dimension with the relative position of winding, is detected the deformation of winding by the short-circuit reactance of monitoring transformer.When transformer generation coil displacements or turn-to-turn short circuit, will there is strong change in stray field.The change of stray field directly has influence on the change of winding leakage inductance, namely affects the change of leakage reactance, and then short-circuit reactance value also just changes.In figure for transformer primary side voltage; for Circuit Fault on Secondary Transformer voltage; for Circuit Fault on Secondary Transformer voltage is at the reduced value of primary side; for transformer primary side current; for Circuit Fault on Secondary Transformer electric current; for Circuit Fault on Secondary Transformer electric current is at the reduced value of primary side; for transformer excitation electric current (or no-load current); Z ₁, R ₁, X ₁the impedance of transformer first side winding, resistance, reactance respectively; Z ₂, R ₂, X ₂the impedance of Circuit Fault on Secondary Transformer winding, resistance, reactance respectively; Z ' ₂, R ' ₂, X ' ₂that the impedance of Circuit Fault on Secondary Transformer winding, resistance, reactance are at the reduced value of primary side respectively; Z ₁₀, R ₁₀, X ₁₀be respectively exciting impedance, resistance, reactance, Z ₁=R ₁+ jX ₁, Z ₂=R ₂+ jX ₂, Z ₁₀=R ₁₀+ jX ₁₀, Z ' ₂=R ' ₂+ jX ' ₂.

By the computing formula of the short-circuit reactance of each phase winding of transformer is obtained as shown in formula (1) after deriving:

$\frac{U_1(\cos {\mathrm{\φ}}_1\·\sin {\mathrm{\φ}}_3-\sin {\mathrm{\φ}}_1\·\cos {\mathrm{\φ}}_3)}{-I_1}-\frac{U_2^{\′}(\cos {\mathrm{\φ}}_2\·\sin {\mathrm{\φ}}_3-\sin {\mathrm{\φ}}_2\·\cos {\mathrm{\φ}}_3)}{-I_1}=X_K---\left(1\right)$

Wherein, K is transformer voltage ratio, X _kfor transformer short-circuit reactance, φ ₁for the phase angle of transformer primary side voltage, φ ₂for the phase angle of Circuit Fault on Secondary Transformer voltage, φ ₃for the phase angle of transformer primary side current, U ₁for the effective value of transformer primary side voltage, U ' ₂for Circuit Fault on Secondary Transformer voltage is at the effective value of the reduced value of primary side, I ₁for the effective value of transformer primary side current.

Step 5.4: the reactance change rate calculating the short-circuit reactance of each phase winding of power transformer and the short-circuit reactance of each phase winding of the trouble-free power transformer of history.

Step 5.5: the upper limit threshold of setting reactance change rate and the lower threshold of reactance change rate, if the reactance change rate of the Winding in Power Transformer obtained is greater than reactance change rate upper limit threshold, then judge that this phase winding of power transformer exists mechanical vibration fault, perform step 6, if the reactance change rate of the Winding in Power Transformer obtained is greater than reactance change rate lower threshold and be less than reactance change rate upper limit threshold, then perform step 5.6, if the reactance change rate of the Winding in Power Transformer obtained is less than reactance change rate lower threshold, then judge that this phase winding of power transformer is normal, perform step 6.

In present embodiment, the upper limit threshold of the setting reactance change rate of setting is 4%, and the lower threshold of reactance change rate is 2%,

Should more than 2% with reference to the short-circuit reactance rate of change specified in GB, for when there is sensor error, in on-line monitoring short-circuit reactance method, the transformer of reactance change rate between 2% ~ 4%, needs arouse attention, when short-circuit reactance rate of change is more than 4%, can determine that mechanical faults occurs in Transformer Winding inside.

Step 5.6: the fundamental frequency amplitude of mechanical oscillation signal corresponding with it for each phase current effective value of Winding in Power Transformer is carried out matching, the fundamental frequency amplitude fitting result of mechanical oscillation signal corresponding with it for each phase current effective value obtained is mated with the fundamental frequency amplitude fitting result of its corresponding mechanical oscillation signal with this phase current effective value of the trouble-free Winding in Power Transformer of history, judge error that matching result exists whether in error allowed band, if, then judge that this phase winding of power transformer is normal, otherwise, then judge that this phase winding of power transformer exists mechanical vibration fault.

The result of determination of each phase winding of transformer is shown by display screen by step 6:MUC, and result of determination comprises: winding is normal, A phase winding mechanical vibration fault, B phase winding mechanical vibration fault, C phase winding mechanical vibration fault and three-phase windings mechanical vibration fault.

Claims (5)

1. the Winding in Power Transformer on-Line Monitor Device of Multi-information acquisition, it is characterized in that, comprise voltage sensor, current sensor, vibration acceleration sensor, phase shift amplifying circuit, signal conditioning circuit, A/D conversion control circuit, DSP, dual port RAM and MCU;

The output terminal of voltage sensor, the output terminal of current sensor are connected the input end of phase shift amplifying circuit respectively with the output terminal of vibration acceleration sensor, the input end of the output terminal connection signal modulate circuit of phase shift amplifying circuit, the output terminal of signal conditioning circuit connects the input end of A/D conversion control circuit, the output terminal of A/D conversion control circuit connects the input end of DSP, and DSP and MCU is connected by dual port RAM;

Current sensor and voltage sensor are connected Current Transformer Secondary side, the voltage transformer secondary side of transformer station respectively;

Vibration acceleration sensor is installed on the correspondence position of power transformer three-phase windings at fuel tank sidewall.

2. the Winding in Power Transformer on-Line Monitor Device of Multi-information acquisition according to claim 1, it is characterized in that, described phase shift amplifying circuit is used for the signal of collection to carry out decoupling and filtering process, comprise operational amplifier, first electric capacity, second electric capacity, 3rd electric capacity, feedback resistance, first slide rheostat and the second slide rheostat, the diode of input end two reversal connections in parallel of operational amplifier, the output terminal of operational amplifier connects one end of the 3rd electric capacity, the other end ground connection of the 3rd electric capacity, the input end of operational amplifier also connects one end of the first slide rheostat, the other end of the first slide rheostat connects one end of feedback resistance, the output terminal of the other end concatenation operation amplifier of feedback resistance, the input end of operational amplifier also connects one end of the second slide rheostat, the other end of the second slide rheostat connects one end of the first electric capacity, the output terminal of the other end concatenation operation amplifier of the first electric capacity, the input end of operational amplifier also connects one end of the second electric capacity, the output terminal of the other end concatenation operation amplifier of the second electric capacity.

3. the Winding in Power Transformer on-Line Monitor Device of Multi-information acquisition according to claim 1, it is characterized in that, described signal conditioning circuit is used for converting simulating signal to fully differential input signal, comprise the first operational amplifier, second operational amplifier, first resistance, second resistance, 3rd resistance, 4th resistance, 5th resistance and the 6th resistance, the negative input end of the first operational amplifier connects one end of the 3rd resistance, the other end ground connection of the 3rd resistance, the positive input terminal of the first operational amplifier connects one end of the 4th resistance, the negative input end of the first operational amplifier also connects one end of the first resistance, the other end of the first resistance connects the output terminal of the first operational amplifier, the positive input terminal of the first operational amplifier also connects one end of the second resistance, the other end of the second resistance connects the output terminal of the second operational amplifier, the negative input end of the second operational amplifier and output terminal short circuit, the output terminal of the first operational amplifier connects one end of the 5th resistance, the other end of the 5th resistance connects the input end of A/D conversion control circuit, the output terminal of the second operational amplifier also connects one end of the 6th resistance, the other end of the 6th resistance connects the input end of A/D conversion control circuit, the positive input terminal of the second operational amplifier connects the input end of A/D conversion control circuit.

4. the Winding in Power Transformer on-Line Monitor Device of Multi-information acquisition according to claim 1, is characterized in that, described A/D conversion control circuit comprises two A/D conversion chips, and the cascade of two A/D conversion chips.

5. adopt the Winding in Power Transformer diagnostic method of the Winding in Power Transformer on-Line Monitor Device of Multi-information acquisition according to claim 1, it is characterized in that, comprise the following steps:

Step 1: voltage sensor gathers three-phase primary side voltage signal and the three-phase secondary side voltage signal of power transformer by the voltage transformer secondary side of transformer station, current sensor gathers the three-phase primary side current signal of power transformer by the Current Transformer Secondary side of transformer station, and vibration transducer gathers the three-phase mechanical vibration signal of power transformer;

Step 2: each phase primary side voltage signal of power transformer, each phase secondary side voltage signal and each phase primary side current signal and each mechanical kilowatt vibration signal of power transformer tank are carried out decoupling and filtering process by phase shift amplifying circuit;

Step 3: each phase primary side voltage signal after decoupling and filtering process, each phase secondary side voltage signal, each phase primary side current signal and each mechanical kilowatt vibration signal are carried out amplitude limiting processing by signal conditioning circuit, make it meet the input range of A/D conversion control circuit;

Each phase primary side voltage signal after amplitude limiting processing, each phase secondary side voltage signal, each phase primary side current signal and each mechanical kilowatt vibration signal are carried out analog to digital conversion by step 4:A/D conversion control circuit, obtain each phase primary side voltage digital signal, each phase secondary side voltage digital signal, each phase primary side current digital signal and each mechanical kilowatt vibration digital signal;

Step 5:DSP adopts short-circuit reactance method and mechanical vibration method to process each phase primary side voltage digital signal, each phase secondary side voltage digital signal, each phase primary side current digital signal and each mechanical kilowatt vibration digital signal, carries out mechanical vibration fault diagnosis to each phase winding of power transformer;

Step 5.1: calculate the phasor of each phase primary side voltage digital signal, phase angle and effective value, each phase secondary side voltage digital signal phasor, phase angle and effective value, each phase primary side current digital signal phasor, phase angle and effective value respectively;

Step 5.2: each mechanical kilowatt vibration digital signal is decomposed by FFT and carries out frequency domain character extraction, obtain the fundamental frequency amplitude of each mechanical kilowatt vibration signal, using the mechanical vibration eigenwert of the fundamental frequency amplitude of each mechanical kilowatt vibration signal as each phase winding of power transformer;

Step 5.3: the online short-circuit reactance model setting up power transformer, using the input as the online short-circuit reactance model of power transformer of each phase primary side voltage digital signal, each phase secondary side voltage digital signal and each primary side current digital signal, calculate the short-circuit reactance of each phase winding of power transformer, using the electric characteristic value of the short-circuit reactance of each for power transformer phase winding as each phase winding of power transformer;

Step 5.4: the reactance change rate calculating the short-circuit reactance of each phase winding of power transformer and the short-circuit reactance of each phase winding of the trouble-free power transformer of history;

Step 5.5: the upper limit threshold of setting reactance change rate and the lower threshold of reactance change rate, if the reactance change rate of the Winding in Power Transformer obtained is greater than reactance change rate upper limit threshold, then judge that this phase winding of power transformer exists mechanical vibration fault, perform step 6, if the reactance change rate of the Winding in Power Transformer obtained is greater than reactance change rate lower threshold and be less than reactance change rate upper limit threshold, then perform step 5.6, if the reactance change rate of the Winding in Power Transformer obtained is less than reactance change rate lower threshold, then judge that this phase winding of power transformer is normal, perform step 6,

Step 5.6: the fundamental frequency amplitude of mechanical oscillation signal corresponding with it for each phase current effective value of Winding in Power Transformer is carried out matching, the fundamental frequency amplitude fitting result of mechanical oscillation signal corresponding with it for each phase current effective value obtained is mated with the fundamental frequency amplitude fitting result of its corresponding mechanical oscillation signal with this phase current effective value of the trouble-free Winding in Power Transformer of history, judge error that matching result exists whether in error allowed band, if, then judge that this phase winding of power transformer is normal, otherwise, then judge that this phase winding of power transformer exists mechanical vibration fault,

The result of determination of each phase winding of power transformer is shown by display screen by step 6:MUC, and result of determination comprises: winding is normal, A phase winding mechanical vibration fault, B phase winding mechanical vibration fault, C phase winding mechanical vibration fault and three-phase windings mechanical vibration fault.