阅读说明：本技术 一种故障指示器用非接触式电场测量系统及方法 (Non-contact electric field measurement system and method for fault indicator ) 是由 吴国强 刘培 于泳 朱德良 王利宁 王先强 刘孟臣 高家皓 董其泉 张珊珊 黄菁 于 2019-11-29 设计创作，主要内容包括：本发明提供了一种故障指示器用非接触式电场测量系统及方法,本发明实施例通过在带电线路上安装设置电场感应片、信号调理单元以及MCU芯片,通过电场感应片将感应出的电压信号输入到信号调理单元,通过信号调理单元输出用于MCU芯片处理的输出信号,从而实现能够使故障指示器适应架空线路不同导线的条件,有效判断线路故障,同时该电路采用非接触方式,可满足带电装卸需求,保证配电网平稳运行。(The invention provides a non-contact electric field measuring system and a non-contact electric field measuring method for a fault indicator.)

1. A non-contact electric field measurement system for a fault indicator, the system being suspended from a line, comprising:

the electric field induction chip, the filter, the primary operational amplification circuit, the secondary operational amplification circuit and the MCU chip are connected in sequence;

the electric field induction sheet induces a voltage signal and inputs the voltage signal into the filter, the filter filters the voltage signal, the signal amplification is carried out through the primary operational amplifier circuit and the secondary operational amplifier circuit, the amplified signal is output to the MCU chip, and the MCU chip judges whether the electric field of the circuit is abnormally changed or not according to the amplified voltage signal.

2. The system of claim 1, wherein the output terminal of the filter is connected to a voltage divider resistor R1, the other terminal of the voltage divider resistor R1 is connected to the inverting input terminal of the first-stage operational amplifier, the inverting input terminal of the first-stage operational amplifier is further connected to a feedback resistor R2, the non-inverting input terminal of the first-stage operational amplifier is connected to a dc bias voltage VREF, the output terminal of the first-stage operational amplifier is connected to a resistor R2, the MCU chip and a voltage divider resistor R3, the inverting input terminal of the second-stage operational amplifier is connected to a voltage divider resistor R3 and a feedback resistor R4, the non-inverting input terminal of the second-stage operational amplifier is connected to a dc bias voltage VREF, and the output terminal.

3. The system of claim 1, wherein the electric field sensing strip is a single brass strip.

4. The system of claim 3, wherein the thickness of the electric field sensor is 1-1.5mm, the electric field sensor is rectangular, and the edge of the electric field sensor is provided with a lead pad connected to the filter via a lead.

5. A method for non-contact electric field measurement using the system of any one of claims 1-4, the method comprising the operations of:

the system is hung on a circuit, a voltage signal is induced through an electric field induction sheet and input into a filter, the filter filters the voltage signal, the signal is amplified through a primary operational amplifier circuit and a secondary operational amplifier circuit, the amplified signal is output to an MCU chip, and the MCU chip judges whether the electric field of the circuit is abnormally changed or not according to the amplified voltage signal.

6. The method according to claim 5, wherein the output terminal of the filter is connected to a voltage divider resistor R1, the other terminal of the voltage divider resistor R1 is connected to the inverting input terminal of the first-stage operational amplifier, the inverting input terminal of the first-stage operational amplifier is further connected to a feedback resistor R2, the non-inverting input terminal of the first-stage operational amplifier is connected to a DC bias voltage VREF, the output terminal of the first-stage operational amplifier is connected to a resistor R2, an MCU chip and a voltage divider resistor R3, the inverting input terminal of the second-stage operational amplifier is connected to a voltage divider resistor R3 and a feedback resistor R4, the non-inverting input terminal of the second-stage operational amplifier is connected to a DC bias voltage VR.

7. The non-contact electric field measurement method for the fault indicator according to claim 5, wherein the electric field induction sheet is a single-layer brass sheet.

8. The non-contact electric field measurement method for the fault indicator according to claim 7, wherein the thickness of the electric field induction sheet is 1-1.5mm, the electric field induction sheet is rectangular, the edge of the electric field induction sheet is provided with a lead bonding pad, and the electric field induction sheet is connected with the filter through a lead.

Technical Field

The invention relates to the technical field of power supply and distribution fault detection, in particular to a non-contact electric field measurement system and a non-contact electric field measurement method for a fault indicator.

Background

Under the normal operation condition of the overhead line low-current system, under the action of the same voltage, the phase electric field strength of three phases is the same, and the three phases keep symmetry. When single-phase earth fault occurs, the strength of the phase electric field changes along with the change of the phase voltage, and the earth characteristic can be reflected through the change of the strength of the phase electric field.

At present, a transient recording type fault indicator is widely applied to an overhead line small current system, a collecting unit of the fault indicator monitors current and a ground electric field of a corresponding phase line, short-circuit faults are indicated on site, recording is triggered when abnormal change of the line current or the line electric field is detected, current and electric field waveforms before and after the abnormal change moment are recorded, and the current and the electric field waveforms are transmitted to a collecting unit through short-distance wireless communication. Through the wave recording function of the fault indicator, the panoramic recording of the fault occurrence and evolution process can be realized, basic data is provided for accurately analyzing the fault reason of the power distribution network, and the current situation that the fault reason can only be presumed by depending on experience is changed.

However, the existing overhead line is made of both insulated conductors and bare conductors, the difference between the ground electric fields of the two conductors is large, and the existing fault indicator does not distinguish the two conductors, so that the electric field sampling accuracy is low, the situations of false alarm, failure in alarm and the like exist, and the fault of the power distribution network cannot be timely and accurately judged. In addition, because the power distribution network has numerous branches and has large power failure influence, the sampling precision of current and electric field is difficult to ensure even if the acquisition unit arranged on the line adopts a live-line loading and unloading mode.

Disclosure of Invention

The invention aims to provide a non-contact electric field measuring system and a non-contact electric field measuring method for a fault indicator, which aim to solve the problem that faults of a power distribution network cannot be accurately judged in the prior art, realize adaptation to conditions of different leads of an overhead line, effectively judge line faults and ensure stable operation of the power distribution network.

In order to achieve the above technical object, the present invention provides a non-contact electric field measurement system for a fault indicator, the system being hung on a line, the system comprising:

the electric field induction chip, the filter, the primary operational amplification circuit, the secondary operational amplification circuit and the MCU chip are connected in sequence;

the electric field induction sheet induces a voltage signal and inputs the voltage signal into the filter, the filter filters the voltage signal, the signal amplification is carried out through the primary operational amplifier circuit and the secondary operational amplifier circuit, the amplified signal is output to the MCU chip, and the MCU chip judges whether the electric field of the circuit is abnormally changed or not according to the amplified voltage signal.

Preferably, the output end of the filter is connected with a voltage dividing resistor R1, the other end of the voltage dividing resistor R1 is connected with the inverting input end of the primary operational amplifier, the inverting input end is further connected with a feedback resistor R2, the non-inverting input end of the primary operational amplifier is connected with a dc bias voltage VREF, the output end is respectively connected with a resistor R2, an MCU chip and a voltage dividing resistor R3, the inverting input end of the secondary operational amplifier is respectively connected with a voltage dividing resistor R3 and a feedback resistor R4, the non-inverting input end of the secondary operational amplifier is connected with a dc bias voltage VREF, and the output end is respectively connected with a resistor R.

Preferably, the electric field induction sheet is a single-layer brass sheet.

Preferably, the thickness of the electric field induction sheet is 1-1.5mm, the electric field induction sheet is rectangular, a lead bonding pad is arranged on the edge of the electric field induction sheet, and the electric field induction sheet is connected with the filter through a lead.

The invention also provides a method for realizing non-contact electric field measurement by using the non-contact electric field measurement system for the fault indicator, which comprises the following operations:

the system is hung on a circuit, a voltage signal is induced through an electric field induction sheet and input into a filter, the filter filters the voltage signal, the signal is amplified through a primary operational amplifier circuit and a secondary operational amplifier circuit, the amplified signal is output to an MCU chip, and the MCU chip judges whether the electric field of the circuit is abnormally changed or not according to the amplified voltage signal.

Preferably, the output end of the filter is connected with a voltage dividing resistor R1, the other end of the voltage dividing resistor R1 is connected with the inverting input end of the primary operational amplifier, the inverting input end is further connected with a feedback resistor R2, the non-inverting input end of the primary operational amplifier is connected with a dc bias voltage VREF, the output end is respectively connected with a resistor R2, an MCU chip and a voltage dividing resistor R3, the inverting input end of the secondary operational amplifier is respectively connected with a voltage dividing resistor R3 and a feedback resistor R4, the non-inverting input end of the secondary operational amplifier is connected with a dc bias voltage VREF, and the output end is respectively connected with a resistor R.

Preferably, the electric field induction sheet is a single-layer brass sheet.

Preferably, the thickness of the electric field induction sheet is 1-1.5mm, the electric field induction sheet is rectangular, a lead bonding pad is arranged on the edge of the electric field induction sheet, and the electric field induction sheet is connected with the filter through a lead.

Drawings

Fig. 1 is a structural diagram of a non-contact electric field measurement system for a fault indicator according to an embodiment of the present invention.

Detailed Description

In order to clearly explain the technical features of the present invention, the following detailed description of the present invention is provided with reference to the accompanying drawings. The following disclosure provides many different embodiments, or examples, for implementing different features of the invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. It should be noted that the components illustrated in the figures are not necessarily drawn to scale. Descriptions of well-known components and processing techniques and procedures are omitted so as to not unnecessarily limit the invention.

The following describes a non-contact electric field measurement system and method for a fault indicator in detail with reference to the accompanying drawings.

As shown in fig. 1, the present invention discloses a non-contact electric field measurement system for fault indicator, said system is hung on the line, it includes:

the electric field induction chip, the filter, the primary operational amplification circuit, the secondary operational amplification circuit and the MCU chip are connected in sequence;

the electric field induction sheet induces a voltage signal and inputs the voltage signal into the filter, the filter filters the voltage signal, the signal amplification is carried out through the primary operational amplifier circuit and the secondary operational amplifier circuit, the amplified signal is output to the MCU chip, and the MCU chip judges whether the electric field of the circuit is abnormally changed or not according to the amplified voltage signal.

The electric field induction sheet is a single-layer brass sheet, the shape and the size of the electric field induction sheet are matched with those of the acquisition unit, and the thickness of the electric field induction sheet is 1-1.5 mm. The electric field induction sheet is rectangular, and the edge is provided with a lead bonding pad which is connected with the filter through a lead.

The electric field sensing chip inputs a sensed voltage signal into the filter, the output end of the filter is connected with a divider resistor R1, the other end of the divider resistor R1 is connected with the inverting input end of the primary operational amplifier, the inverting input end is further connected with a feedback resistor R2, the non-inverting input end of the primary operational amplifier is connected with a direct current bias voltage VREF, the output end of the primary operational amplifier is respectively connected with a resistor R2, an MCU chip and a divider resistor R3, the inverting input end of the secondary operational amplifier is respectively connected with a divider resistor R3 and a feedback resistor R4, the non-inverting input end of the secondary operational amplifier is connected with a direct current bias voltage VREF, and the output end of.

When the acquisition unit is hung on a line and current exists in the line, the electric field induction sheet inputs an induced voltage signal VDD0 into the filter, the filter can filter noise waves in the voltage signal, the resistors R1 and R2 are adjusted to obtain resistance values, the voltage signal can be subjected to primary amplification, the amplified signal is alternating current voltage taking VREF as a central axis, the resistance values of the resistors R3 and R4 are adjusted, the voltage signal can be subjected to secondary amplification, and the amplified signal is also alternating current voltage taking VREF as the central axis. When the circuit is the insulated wire, induced voltage signal VDD0 is less, and through the second grade enlargies can more effective monitoring circuit electric field change, the MCU chip passes through I O2 and judges whether unusual the change appears in the circuit electric field. When the circuit is a bare conductor, the induced voltage signal VDD0 is large, after secondary amplification, the waveform has the phenomenon of peak clipping distortion, the monitoring of a circuit electric field can be met by using a primary amplification signal, and the MCU chip judges whether the circuit electric field is abnormally changed or not through I O1.

The model of the two-way operational amplifier is preferably MCP6422, the power supply voltage of the MCU chip is 3.3V, and VREF is 1.25 direct-current voltage. The static power consumption of each path of amplifier of the operational amplifier MCP6422 is 4.4uA, and the current limiting resistor at the level of peripheral megaohms is added, so that the current consumption of the whole circuit is about 10uA, and the cost is saved on the premise of meeting the measurement accuracy.

According to the embodiment of the invention, the electric field induction sheet, the signal conditioning unit and the MCU chip are arranged on the live line, the induced voltage signal is input to the signal conditioning unit through the electric field induction sheet, and the output signal for processing by the MCU chip is output through the signal conditioning unit. The fault indicator can adapt to the conditions of different leads of an overhead line, the line fault can be effectively judged, and meanwhile, the circuit adopts a non-contact mode, so that the live loading and unloading requirements can be met, and the stable operation of a power distribution network is ensured.

The embodiment of the invention also discloses a non-contact electric field measuring method, which comprises the following operations:

the system is hung on a circuit, a voltage signal is induced through an electric field induction sheet and input into a filter, the filter filters the voltage signal, the signal is amplified through a primary operational amplifier circuit and a secondary operational amplifier circuit, the amplified signal is output to an MCU chip, and the MCU chip judges whether the electric field of the circuit is abnormally changed or not according to the amplified voltage signal.

The electric field induction sheet, the filter, the first-stage operational amplification circuit, the second-stage operational amplification circuit and the MCU chip are connected in sequence.

The electric field induction sheet is a single-layer brass sheet, the shape and the size of the electric field induction sheet are matched with those of the acquisition unit, and the thickness of the electric field induction sheet is 1-1.5 mm. The electric field induction sheet is rectangular, and the edge is provided with a lead bonding pad which is connected with the filter through a lead.

The electric field sensing chip inputs a sensed voltage signal into the filter, the output end of the filter is connected with a divider resistor R1, the other end of the divider resistor R1 is connected with the inverting input end of the primary operational amplifier, the inverting input end is further connected with a feedback resistor R2, the non-inverting input end of the primary operational amplifier is connected with a direct current bias voltage VREF, the output end of the primary operational amplifier is respectively connected with a resistor R2, an MCU chip and a divider resistor R3, the inverting input end of the secondary operational amplifier is respectively connected with a divider resistor R3 and a feedback resistor R4, the non-inverting input end of the secondary operational amplifier is connected with a direct current bias voltage VREF, and the output end of.

When the acquisition unit is hung on a line and current exists in the line, the electric field induction sheet inputs an induced voltage signal VDD0 into the filter, the filter can filter noise waves in the voltage signal, the resistors R1 and R2 are adjusted to obtain resistance values, the voltage signal can be subjected to primary amplification, the amplified signal is alternating current voltage taking VREF as a central axis, the resistance values of the resistors R3 and R4 are adjusted, the voltage signal can be subjected to secondary amplification, and the amplified signal is also alternating current voltage taking VREF as the central axis. When the circuit is the insulated wire, induced voltage signal VDD0 is less, and through the second grade enlargies can more effective monitoring circuit electric field change, the MCU chip passes through I O2 and judges whether unusual the change appears in the circuit electric field. When the circuit is a bare conductor, the induced voltage signal VDD0 is large, after secondary amplification, the waveform has the phenomenon of peak clipping distortion, the monitoring of a circuit electric field can be met by using a primary amplification signal, and the MCU chip judges whether the circuit electric field is abnormally changed or not through I O1.

The model of the two-way operational amplifier is preferably MCP6422, the power supply voltage of the MCU chip is 3.3V, and VREF is 1.25 direct-current voltage. The static power consumption of each path of amplifier of the operational amplifier MCP6422 is 4.4uA, and the current limiting resistor at the level of peripheral megaohms is added, so that the current consumption of the whole circuit is about 10uA, and the cost is saved on the premise of meeting the measurement accuracy.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.