CN104111027B - Lissajous figure analytical method based transformer power frequency signal sensor system - Google Patents

Abstract

The purpose of the invention is to solve the measurement and conversion of online voltage and current values meeting the requirements in the Lissajous figure analysis method. The technical scheme adopted for realizing the object of the present invention is as follows, the transformer power frequency signal sensor system based on the Lissajous figure analysis method includes a transformer and a signal processing circuit. The transformer is used to collect the voltage or current of the transformer. The signal processing circuit includes two input terminals and one output terminal. The invention can effectively suppress common-mode interference, convert differential signals into single-ended signals, and simultaneously filter out harmonic signals other than power frequency fundamental waves.

Description

Transformer power frequency signal sensor system based on Lissajous graph analysis method

technical field

The invention relates to the technical field of online monitoring of electric equipment.

Background technique

In the field of transformer winding deformation fault detection, detection methods such as short-circuit reactance method, winding capacitance method and frequency response method have been proposed. The technology is relatively mature, and there are already relevant regulations and standards. However, the off-line detection method requires the transformer to be shut down, which directly affects the normal operation of the power grid. At the same time, offline monitoring can only be carried out periodically, and cannot reflect the deformation fault of the winding in time. In particular, the off-line detection cycle is long, it is easy to ignore the cumulative effect of winding deformation, and it is difficult to avoid the serious deformation of the winding caused by the cumulative effect; in addition, the online operation and the offline operation state are different, and the offline detection is difficult to find that some online operation states have significant Characteristic of winding deformation faults. Therefore, it is imperative to carry out research on online monitoring methods for transformer winding deformation faults.

The short-circuit impedance method, mechanical vibration method, electromagnetic wave measurement method and ultrasonic ranging method proposed at this stage for online monitoring of winding deformation faults have certain defects. Therefore, it is proposed to analyze winding deformation faults based on transformer online voltage and current Lissajous characteristics. Methods.

Since the existing power transformer itself is equipped with a voltage sensor (PT) and a current sensor (CT), it can be directly used as a measuring device. However, the results of PT and CT measurement output of the transformer set are not convenient for data acquisition and processing of subsequent acquisition cards.

Contents of the invention

The purpose of the invention is to solve the measurement and conversion of online voltage and current values meeting the requirements in the Lissajous figure analysis method.

The technical solution adopted to realize the object of the present invention is as follows: the transformer power frequency signal sensor system based on Lissajous figure analysis method is characterized in that it includes a transformer and a signal processing circuit.

The transformer is used to collect the voltage or current of the transformer.

The signal processing circuit includes two input terminals and one output terminal.

The two input terminals of the signal processing circuit are connected with the output terminals of the transformer.

The first input terminal of the signal processing circuit is connected in series with the first resistor, the third resistor and the fourth resistor in sequence, and then grounded.

The second input terminal of the signal processing circuit is connected to the output terminal of the first integrated operational amplifier after being connected in series with the second resistor, the fifth resistor and the sixth resistor in sequence.

One end of the first capacitor is connected between the first resistor and the third resistor, and the other end is connected to the second capacitor. One end of the second capacitor is connected between the second resistor and the fifth resistor, and the other end is connected to the first capacitor. The connection between the first capacitor and the second capacitor is grounded.

The non-inverting input terminal of the first integrated operational amplifier is connected between the third resistor and the fourth resistor. The inverting input terminal of the first integrated operational amplifier is connected between the fifth resistor and the sixth resistor.

The output terminal of the first integrated operational amplifier is connected to the non-inverting input terminal of the second integrated operational amplifier after the seventh resistor and the eighth resistor are serially connected in series.

The inverting input terminal of the second integrated operational amplifier is connected in series between the seventh resistor and the eighth resistor after the tenth resistor and the fourth capacitor are connected in series.

The inverting input end of the second integrated operational amplifier is also connected to one end of the ninth resistor. The other end of the ninth resistor is connected in series with the third capacitor to the output end of the first integrated operational amplifier. The output terminal of the second integrated operational amplifier is connected between the ninth resistor and the third capacitor.

The output end of the second integrated operational amplifier is the output end of the signal processing circuit.

Further, both the first integrated operational amplifier and the second integrated operational amplifier are OP07 chips.

Further, the transformer is a miniature voltage transformer or a miniature current transformer.

The technical effect of the present invention is beyond doubt. Specifically, the present invention can accurately convert the measured values of the transformer set of PTs and CTs into signals suitable for processing. The sensor system has high enough precision, and the rated operating frequency, voltage and current can match the transformer set of PTs and CTs.

Description of drawings

Figure 1 is a schematic diagram of the sensor system;

Figure 2 is a circuit diagram of the system.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and embodiments, but it should not be understood that the scope of the subject matter of the present invention is limited to the following embodiments. Without departing from the above-mentioned technical ideas of the present invention, various replacements and changes made according to common technical knowledge and conventional means in this field shall be included in the protection scope of the present invention.

Transformer power frequency signal sensor system based on Lissajous graph analysis method, including transformer and signal processing circuit.

The transformer is used to collect the voltage or current of the transformer. The transformers cooperate with voltage transducers (PT) and current transducers (CT) installed on the existing power transformer itself. Specifically, when the transformer is a miniature voltage transformer, its model is SKPT100100V/1.73V (a pin-type voltage transformer with a precision of 0.1, a rated operating voltage of 100 V, and a rated operating frequency of 50-400 Hz , Transformation ratio 100V: 1.73V.), including two input ports and two output ports. The input port of the voltage transformer inputs the signal collected by the voltage sensor (PT), and the output port is connected with the signal processing circuit. When the transformer is a miniature current transformer, its model is HLX15A/2.5mA 0.0520Ω (pin-type current sensor with a precision of 0.1 grade, transformation ratio 5 A: 2.5 mA, secondary rated load 24Ω), including a An input port, two output ports, and two fixed ports. The input port of the current transformer inputs the signal collected by the current sensor (CT), and the output port is connected with the signal processing circuit.

The signal processing circuit includes two input terminals and one output terminal.

The two input terminals of the signal processing circuit are connected with the output terminals of the transformer.

The first input terminal of the signal processing circuit is connected in series with the first resistor R1, the third resistor R3 and the fourth resistor R4 in sequence, and then grounded.

The second input terminal of the signal processing circuit is connected to the output terminal of the first integrated operational amplifier after connecting the second resistor R2, the fifth resistor R5 and the sixth resistor R6 in series in sequence.

One end of the first capacitor C1 is connected between the first resistor R1 and the third resistor R3, and the other end is connected to the second capacitor C2. One end of the second capacitor C2 is connected between the second resistor R2 and the fifth resistor R5, and the other end is connected to the first capacitor C1. The connection between the first capacitor C1 and the second capacitor C2 is grounded.

The non-inverting input terminal of the first integrated operational amplifier is connected between the third resistor R3 and the fourth resistor R4. The inverting input terminal of the first integrated operational amplifier is connected between the fifth resistor R5 and the sixth resistor R6.

The output terminal of the first integrated operational amplifier is connected to the non-inverting input terminal of the second integrated operational amplifier after the seventh resistor R7 and the eighth resistor R8 are serially connected in series.

The inverting input end of the second integrated operational amplifier is connected in series between the seventh resistor R7 and the eighth resistor R8 after the tenth resistor R10 and the fourth capacitor C4 are connected in series.

The inverting input end of the second integrated operational amplifier is also connected to one end of the ninth resistor R9. The other end of the ninth resistor R9 is connected in series with the third capacitor C3 to the output end of the first integrated operational amplifier. The output terminal of the second integrated operational amplifier is connected between the ninth resistor R9 and the third capacitor C3.

The output end of the second integrated operational amplifier is the output end of the signal processing circuit.

In an embodiment, both the first integrated operational amplifier and the second integrated operational amplifier are OP07 chips. The OP07 chip is a low-noise, non-chopper-stabilized bipolar (dual power supply) operational amplifier integrated circuit.

The present invention can effectively suppress common-mode interference, convert differential signals into single-ended signals, filter out harmonic signals other than the power frequency fundamental wave, and adjust the signal amplitude to 2.5 V, and its component parameters satisfy R ₁ =R ₂ =R ₃ =R ₄ , R ₅ C ₁ =R ₆ C ₂ =0.0016. When the transformer is a miniature voltage transformer, if the amplification factor is 1.02, the condition R ₈ /R ₇ =0.02 must be satisfied. When the transformer is a miniature current transformer, if the amplification factor is 29.46, the condition R ₈ /R ₇ =28.46 must be satisfied.

Claims (2)

1. the transformer power frequency component sensing system based on Lie groupoid analytic approach it is characterised in that：Including transformer and letter Number process circuit；

Described transformer is used for gathering voltage or the electric current of transformer；

Described signal processing circuit includes two inputs and an output end；

Two inputs of described signal processing circuit are connected with the output end of described transformer；

The first input end of described signal processing circuit is sequentially connected in series first resistor R1,3rd resistor R3 and the 4th resistance R4 and is followed by Ground；

Second input of described signal processing circuit is sequentially connected in series second resistance R2, after the 5th resistance R5 and the 6th resistance R6, It is connected to the output end of the first integrated transporting discharging；

One end of first electric capacity C1 is connected between first resistor R1 and 3rd resistor R3, the other end connects the second electric capacity C2；Institute State second electric capacity C2 one end be connected between second resistance R2 and the 5th resistance R5, the other end connect the first electric capacity C1；Described One electric capacity C1 and the second electric capacity C2 indirectly；The input in the same direction of described first integrated transporting discharging is connected to 3rd resistor R3 and Between four resistance R4；The reverse input end of described first integrated transporting discharging is connected between the 5th resistance R5 and the 6th resistance R6；

After the output end of described first integrated transporting discharging is sequentially connected in series the 7th resistance R7 and the 8th resistance R8, it is connected to the second integrated fortune The input in the same direction put；

After the reverse input end of described second integrated transporting discharging is sequentially connected in series the tenth resistance R10 and the 4th electric capacity C4, it is connected to the 7th Between resistance R7 and the 8th resistance R8；

The reverse input end of described second integrated transporting discharging is also connected with one end of the 9th resistance R9；Described 9th resistance R9's is another After end series connection the 3rd electric capacity C3, it is connected to the output end of described first integrated transporting discharging；The output end of the second integrated transporting discharging is connected to Between 9th resistance R9 and the 3rd electric capacity C3；

The output end of described second integrated transporting discharging is the output end of described signal processing circuit；

Component parameters meet R1=R2=R3=R4, R5C1=R6C2=0.0016；When described transformer is miniature mutual induction of voltage During device, if multiplication factor is 1.02, need to meet condition R8/R7=0.02；When described transformer is micro-transformer of current, If multiplication factor is 29.46, need to meet condition R8/R7=28.46；

Described first integrated transporting discharging and the second integrated transporting discharging are OP07 chip.

2. the transformer power frequency component sensing system based on Lie groupoid analytic approach according to claim 1, its feature It is：Described transformer is Micro-Transformer of Voltage or micro-transformer of current.