CN101299385A - Electron type current transformer for ultrahigh voltage transmission lines and corona loss measurement device thereof - Google Patents

Abstract

A ultra-high voltage transmission line electron type current transformer and the corona loss measurement device, including an electron type current transformer 1.3, a ultra-high voltage capacitance type voltage transformer 1.4, a second divided voltage core loop 1.9 and an industrial control computer, wherein the electron type current transformer 1.3 includes a resistance sample unit 2.1, a distance module 2.2, an optical fiber compound insulator 2.7 and a local module 2.8, and the resistance sample unit 2.1 is electrically connected with the distance module 2.2, while the distance module 2.2 is optically connected with the local module 2.8 through the optical fiber compound insulator 2.7; the output of the local module 2.8 is connected with the DAQ-2006 data acquisition card of the industrial control computer; the resistance sample unit 2.1 and the distance module 2.2 are hung at the start end of the phase conduct; the ultra-high voltage capacitance type voltage transformer 1.4 on the bushing line outgoing end of the ultra-high voltage transformer 1.1, wherein the secondary winding connection end of the middle transformer is electrically connected with the second divided voltage core loop 1.9, the output signal of which is performed with the electrical transformation/ optical transformation, and is transmitted to the local module 2.8 for voltage measurement, then is collected by the DAQ-2006 data acquisition card of the industrial control computer, which has high measurement accuracy, no insulation, convenient operation, no safety hidden trouble.

Description

Electronic current transformer for UHV transmission line and its corona loss measuring device

technical field

The invention belongs to the field of high-voltage measurement of transmission lines, and relates to a corona loss measurement device, in particular to a corona loss measurement device for UHV transmission lines, which is suitable for long-term monitoring of corona loss of 1000kV voltage level transmission lines The measurement and evaluation of the power loss of the 1000kV voltage level transmission line is also of great significance to the selection of the conductor structure of the UHV transmission line.

Background technique

When the electric field strength around the wires of the transmission line exceeds the breakdown field strength of the air, the air near the wires is ionized to form a corona discharge. The charged ions produced by corona discharge move back and forth around the wire under the action of alternating voltage, accompanied by air ionization and light and radio interference. The energy consumed by these effects is collectively referred to as corona loss.

When determining the conductor structure of a 1000kV UHV transmission line, not only the resistance loss when the conductor passes current, but also the corona loss under different conductor structure conditions must be considered. Under some special conditions, the climate in the area where the line passes is very bad, and rain, snow, frost, and fog account for a large proportion of the year, and the total loss of electric energy caused by corona loss may become the main controlling factor.

In the 1960s and 1970s, the United States, the former Soviet Union, Canada, Italy, France, Japan and other countries successively established test line sections for the construction of transmission lines in various countries, and carried out measurement research on corona loss. Due to the limitation of the transmission voltage level of each country, the corona loss research carried out by most countries is limited to ultra-high voltage transmission lines, and only a few countries such as the United States, the former Soviet Union and Italy have done relevant tests on UHV test lines. So far, such UHV corona loss tests in foreign countries last for a short period of time, and the meteorological conditions experienced by the tests are not complete, resulting in incomplete test data. Further long-term tests and actual measurement research are required.

Before the construction of the 330kV line in Northwest my country in the early days, in order to obtain the design basis of corona loss, corresponding test line sections were established in Qinghe, Beijing and Haizitou, Yunnan, and the measurement and research of corona loss were carried out. Then the Qinghe 330kV line section was rebuilt into a 500kV line section to measure the corona loss of the 500kV line. Wuhan High Voltage Research Institute built a 1km500kV test line section in Wuhan in the 1980s, and measured the corona loss of the line. But so far, the corona loss measurement of UHV transmission lines in my country has basically not been carried out, and the relevant calculations of UHV corona loss basically refer to relevant foreign data, and such reference data are few and far from complete.

my country is currently actively conducting research on UHV technology. The research on corona loss of transmission lines is one of the key technologies of 1000kV UHV power transmission and transformation projects in my country. It is urgent to develop a device that can accurately measure corona loss of UHV transmission lines for a long time . The early corona loss measurement was often carried out by using the Xilin bridge modified for automatic balance, and the measurement of the test line section needs to be reversed, and the bridge is in the high potential area. This measurement method is inconvenient to operate, and there are certain safety hazards to people and equipment, and it is difficult to realize real-time online detection under different climatic conditions for a long time.

Traditional high-voltage current measurement uses an electromagnetic current transformer (Current Transformer, CT) based on the principle of electromagnetic induction. It uses an iron core coil for the measurement channel and a Rogowski coil for the protection channel. The accuracy of the traditional electromagnetic CT to measure the steady-state current can reach a few ten-thousandths or even higher. However, with the continuous increase of the power system capacity and the continuous improvement of the voltage level, the electromagnetic CT is getting more and more difficult due to its own principle defects. It is becoming more and more difficult to meet the development needs of the power system. In the case of a short-circuit fault, the iron core coil will experience serious magnetic saturation, resulting in severe distortion of the secondary output current waveform, which cannot accurately reflect the transition process during the short-circuit. In the case of distortion of the current waveform, the accuracy of the Rogowski coil is not high enough. Therefore, the traditional electromagnetic CT cannot reflect the current information very accurately when the current waveform is distorted.

Contents of the invention

The object of the present invention is to provide an electronic current transformer for UHV transmission lines and a corona loss measurement device for the defects of the traditional corona loss measurement method, which has high measurement accuracy, no insulation problem, and easy operation. It is convenient, there is no potential safety hazard, and it can realize long-time on-line measurement of corona loss of UHV transmission lines.

The technical solution of the present invention is: an electronic current transformer for UHV transmission lines, characterized in that it includes a resistance sampling unit 2.1, a remote module 2.2, an optical fiber composite insulator 2.7 and a local module 2.8, and a resistance sampling unit 2.1 remote The module 2.2 is electrically connected, and the remote module 2.2 is optically connected to the local module 2.8 through an optical fiber composite insulator 2.7;

The resistance sampling unit 2.1 includes a front conductive copper rod 3.1, a copper foil 3.2, a circuit board 3.3, a precision non-inductive resistor 3.4 and a rear conductive copper rod 3.1 electrically connected in sequence;

The remote module 2.2 includes an electrically connected high-voltage side A/D conversion module 2.3 and an electrical/optical conversion module 2.5, and the photoelectric energy conversion module 2.6 is electrically connected to the high-voltage side A/D conversion module 2.3 and the electrical/optical conversion module 2.5 respectively ;

The local module 2.8 includes signal processing circuit and D/A conversion module 2.9, optical/electrical conversion module 2.10, laser device 2.11, power supply 2.12, drive circuit 2.13; optical/electrical conversion module 2.10 and signal processing circuit and D/A conversion The module 2.9 is electrically connected, the driving circuit 2.13 is electrically connected to the laser 2.11, and the power supply 2.12 provides electric energy to the signal processing circuit and the D/A conversion module 2.9, the optical/electrical conversion module 2.10, the driving circuit 2.13 and the laser 2.11;

Both ends of the precision non-inductive resistor 3.4 in the resistance sampling unit 2.1 output voltage signals to the high-voltage-side A/D conversion module 2.3 in the remote module 2.2.

A device for measuring corona loss of UHV transmission lines using the above-mentioned electronic current transformer for UHV transmission lines, characterized in that it includes electronic current transformer 1.3, UHV capacitive voltage transformer 1.4, secondary divider Compression iron core coil 1.9 and industrial computer;

The electronic current transformer 1.3 includes a resistance sampling unit 2.1, a remote module 2.2, an optical fiber composite insulator 2.7 and a local module 2.8, the resistance sampling unit 2.1 is electrically connected to the remote module 2.2, and the remote module 2.2 is optically connected to the local module 2.8 through the optical fiber composite insulator 2.7. Connection; the output of the local module 2.8 is connected with the DAQ-2006 data acquisition card of the industrial computer;

The resistance sampling unit 2.1 and the remote module 2.2 of the electronic current transformer 1.3 are suspended at the beginning of the phase wire;

The UHV capacitive voltage transformer 1.4 is installed at the outlet end of the UHV transformer 1.1 bushing, and the secondary winding terminal of the UHV capacitive voltage transformer 1.4 intermediate transformer is electrically connected with the iron core coil 1.9 for secondary voltage division. The output signal of the iron core coil 1.9 for voltage division is converted into electricity/light, transmitted to the local module 2.8 for voltage measurement with an optical cable, and then collected by the DAQ-2006 data acquisition card of the industrial computer.

The above-mentioned corona loss measurement device for UHV transmission lines is characterized in that: the industrial computer is electrically connected to the wind speed sensor 1.5, the temperature and humidity sensor 1.6 and the instantaneous rain gauge 1.7 respectively.

The principle of the invention is: the current signal extraction part adopts an electronic current transformer, and uses a high-power precision non-inductive resistor as a current sensor, which can ensure that the resistor itself will not be damaged by transient voltage and current. Connect the resistor in series to the UHV transmission line conductor, and because the resistance is precise and non-inductive, the current in the conductor flows through the resistor, and a voltage signal with the same phase as the conductor current is generated at both ends of the resistor to ensure that the waveform has no distortion and can accurately reflect Current information, through electro-optical conversion, uses optical fiber to transmit current signal, and restores the current signal through photoelectric conversion in the control room to realize accurate and reliable measurement of UHV transmission line current; the voltage signal extraction part adopts 1000kV capacitor voltage transformer (CVT), After secondary voltage division and electro-optical conversion, the voltage signal is transmitted by optical fiber, and the voltage signal is restored by photoelectric conversion in the control room to achieve accurate and reliable measurement of voltage. The DAQ-2006 data acquisition card is used to collect voltage and current signals, and software is developed based on virtual instrument technology to calculate corona loss in real time.

The present invention has following beneficial effect:

1. When the current is distorted, it can accurately reflect the current information

High-power precision non-inductive resistors are used as current sensors, which can ensure that the resistance itself will not be damaged by transient voltage and current. The precision non-inductive resistors are connected in series to the wires of UHV transmission lines, and the current in the wires flows through the resistors. A voltage signal is generated at both ends of the resistor. Since the resistor is precise and non-inductive, the generated voltage signal is in the same phase as the wire current signal, ensuring that the waveform will not undergo secondary distortion. Since the high-voltage end is not grounded and equipotential, the data information is transmitted by optical fiber, with simple insulation, strong anti-electromagnetic interference capability, compact structure, small size, light weight, and low overall cost. The electronic current transformer meets the 0.2 level requirements stipulated in the IEC standard, and can accurately measure the current of UHV transmission lines.

2. Easy to operate, no safety hazard

The voltage and current signals are transmitted through optical fibers, so that there is no electrical connection between the high-voltage end and the low-voltage end, and there is no electrical insulation problem. The software operation is performed on the industrial computer in the main control room, which is easy to operate and has no potential safety hazards.

3. Can realize long-term online measurement

The whole device can run around the clock, measure voltage and current signals in real time through 1000kV capacitive voltage transformers and electronic current transformers, calculate and analyze the collected data in real time, and obtain corona loss results, thus realizing long-term online measurement. And it can automatically save the corona loss monitoring results, which can be combined with the meteorological parameters at that time in the future to lay the foundation for further in-depth research on the corona loss law of UHV transmission lines.

Description of drawings

Fig. 1 is a schematic structural diagram of a corona loss measurement device for UHV transmission lines according to an embodiment of the present invention.

Fig. 2 is a schematic structural diagram of an electronic current transformer 1.3 according to an embodiment of the present invention.

FIG. 3 is a schematic structural diagram of the resistance sampling unit 2.1 in FIG. 2 .

Fig. 4, the structural diagram of circuit board 3.3 in Fig. 3.

Figure 5. Electrical connection diagram of resistance sampling unit 2.1.

Figure 6. 1000kV capacitive voltage transformer.

Figure 7. Software flow diagram.

Figure 8. Corona loss monitoring results.

Detailed ways

Instructions marked in Figure 1: 1.1-UHV transformer; 1.2-UHV line; 1.3-Electronic current transformer; 1.4-Capacitive current transformer; 1.5-Wind speed sensor; 1.6-Temperature and humidity sensor; 1.7-Instantaneous rainfall 1.8-industrial computer.

Instructions marked in Figure 2: 2.1-resistance sampling unit; 2.2-remote module; 2.3-high voltage side A/D conversion module; 2.4-high voltage side digital signal; 2.5-electric/optical conversion module; 2.6-photoelectric energy conversion module; 2.7-optical fiber insulator; 2.8-local module; 2.9-signal processing circuit and D/A module; 2.10-optical/electrical conversion; 2.11-laser; 2.12-power supply; 2.13-drive circuit; 2.14-output port.

Instructions marked in Figure 3: 3.1-conductive copper rod; 3.2-copper foil; 3.3-circuit board; 3.4-precision non-inductive resistor; 3.5-screw; 3.6-epoxy resin board.

Instructions marked in Figure 4: 3.4-precision non-inductive resistor; 4.1-copper clad; 4.3-transient voltage suppressor; 4.4-varistor; 4.5-serial input end of precision resistor; 4.7 - Measurement terminals.

Explanation of marks in Fig. 5: 5.1-sub-conductor; 5.2-insulation connecting plate; 5.3-wave trap; 3.4-precision non-inductive resistor.

Instructions marked in Figure 6: 6.1-high voltage capacitor; 6.2-medium voltage capacitor; 6.3-compensation reactor; 6.4-damping device; 6.5-protection device; 6.6-carrier communication terminal; 6.9-Primary voltage terminal of electromagnetic device; 6.10-Secondary winding terminal; 6.11-Residual voltage winding terminal and damper winding terminal; 6.12-Low voltage terminal of compensation reactor.

The present invention will be described in further detail below in conjunction with the accompanying drawings.

The invention is suitable for the long-term monitoring of the corona loss of the 1000kV voltage level transmission line, and also suitable for the measurement and evaluation of the power loss of the 1000kV voltage level transmission line.

As shown in Figure 1, the basic structure of the embodiment of the present invention is mainly composed of the current signal extraction part, the voltage signal extraction part, and the corona loss calculation. 1.7 and other devices to obtain the corresponding meteorological parameters.

As shown in Figure 2, Figure 3, and Figure 4, the circuit board 3.3 is designed by using the resistance sampling unit 2.1 of the electronic current transformer 1.3, and the customized precision non-inductive resistance 3.4 is connected in series to the resistance sampling unit 2.1, and the resistance sampling unit 2.1 metal fittings are shielded, and a transient voltage suppressor (Transient Voltage Suppressor, TVS) 4.3 and varistor 4.4 are installed at the same time to protect the corona loss measurement device of the UHV transmission line. Combining the advantages of high insulation and anti-electromagnetic interference of the optical fiber transmission system, the current signal is extracted at the high-voltage side, modulated into a digital electrical signal by the A/D conversion module 2.3 on the high-voltage side, and then converted into a digital optical signal by the electrical/optical conversion module 2.5 , transmitted to the low-voltage end through the optical fiber in the fiber composite insulator 2.7, converted into a digital electrical signal by the optical/electrical conversion module 2.10, and then demodulated by the signal processing circuit and the D/A module 2.9 to restore a weak electrical signal proportional to the current to be measured , and obtain current magnitude and phase information. The signal is transmitted to the main control room and collected by the data acquisition card installed in the industrial control computer. DAQ-2006 high-precision multi-channel high-speed synchronous data acquisition card is adopted, and its performance parameters are as follows: 4-channel analog input (AI) synchronous acquisition, sampling resolution 16 bits, adjustable gain, sampling range of ±1.25V, ±2.5V, ±5V, ±10V, the highest sampling rate is 250KS/s,

The resistance sampling unit 2.1 and the remote module 2.2 of the electronic current transformer 1.3 of the side phase are suspended in the squirrel cage jumper through the processed mechanical fasteners, and the resistance sampling unit 2.1 and the resistance sampling unit 2.1 of the electronic current transformer 1.3 of the middle phase are The distal module 2.2 is suspended in the pressure equalizing ring through machined mechanical fasteners. The conductive copper rod 3.1 of the resistance sampling unit 2.1 is connected in series with the phase conductor 5.1 through the wave trap 5.3 (see accompanying drawing 5).

As shown in Figure 1, a 1000kV capacitor voltage transformer (CVT) is used to measure the phase voltage of UHV transmission lines.

The software flow is shown in Figure 7. The measured voltage signal and current signal are transmitted to the main control room by optical cable, and demodulated by the electronic current transformer local module 2.8 integrated in the industrial control computer cabinet. Based on the idea of "software is equipment" on the industrial control computer, virtual instrument technology and DAQ-2006 high-precision synchronous data acquisition card are used to realize accurate and synchronous measurement of voltage signals and current signals. Using the UHV transmission line corona loss monitoring system developed by LabVIEW software, the inherent error of the system is compensated by the software method, and the measurement accuracy of the UHV transmission line corona loss is improved. Extract the power frequency components of the voltage signal and current signal, and use the sine wave algorithm to accurately obtain the initial phase of the voltage signal and current signal through the quadrant judgment and phase correction of the initial phase of the voltage signal and current signal, so as to obtain the voltage signal And the power factor angle of the power frequency component of the current signal, and then calculate the corona loss value.

The working process of the embodiment of the present invention is: the precision non-inductive resistor 3.4 is connected in series to the conductor of the UHV transmission line, the current in the conductor flows through the precise non-inductive resistor 3.4, and a voltage signal is generated at both ends of the precise non-inductive resistor 3.4, here The voltage signal is an analog signal, which is transmitted to the A/D conversion module 2.3 on the high-voltage side through the signal wire, converted into a digital electrical signal, and then converted into a digital optical signal through the electrical/optical conversion module 2.5. The resistance sampling unit 2.1 and the high-voltage side A/D conversion module 2.3, electric/optical conversion module 2.5 and photoelectric energy conversion module 2.6 of the remote module located on the high-voltage side are all installed in the shielding fitting. The digital optical signal of the digital current signal is transmitted to the local module 2.8 in the main control room on the low-voltage side through the signal optical fiber, converted into a digital electrical signal through the optical/electrical conversion module 2.10, and then passed through the signal processing circuit and the D/A conversion module 2.9 Reverted to the analog signal of UHV transmission line current, the signal is collected by the DAQ-2006 data acquisition card of the industrial computer.

The high-power precision non-inductive resistor 3.4 is used as a current sensor, which can ensure that the resistor itself will not be damaged by transient voltage and current. The precision non-inductive resistor is connected in series to the wire of the UHV transmission line. Inductance, so the generated voltage signal is in the same phase as the wire current signal, which ensures that the waveform will not undergo secondary distortion, so that the current information can be accurately reflected. The energy optical fiber transmits electrical energy to the photoelectric energy conversion module 2.6, and then the photoelectric energy conversion module 2.6 converts light energy into electrical energy to supply energy for the high-voltage side A/D conversion module 2.3 and the electrical/optical conversion module 2.5.

The UHV capacitive voltage transformer 1.4 is installed at the outlet end of the bushing of the UHV transformer 1.1, the secondary winding terminal of the UHV capacitive voltage transformer 1.4 intermediate transformer is connected with the iron core coil 1.9 for secondary voltage division, and the voltage signal passes through After the second voltage division, the modulation, transmission and demodulation of the signal are the same as the principle of the current signal extraction part. After the voltage signal on the high-voltage side is divided twice, it is transmitted to the A/D conversion module 2.3 on the high-voltage side through the signal wire, converted into a digital electrical signal, and then converted into a digital optical signal through the electrical/optical conversion module 2.5. During the process of A/D conversion and electrical/optical conversion, the high-voltage side A/D conversion module 2.3 and the electrical/optical conversion module 2.5 both need electric energy, and the energy optical fiber transmits the electric energy to the photoelectric energy conversion module 2.6, and then the photoelectric energy conversion The module 2.6 converts light energy into electrical energy, and supplies energy for the high-voltage side A/D conversion module 2.3 and the electrical/optical conversion module 2.5. The iron core coil 1.9 for the secondary voltage division, the A/D conversion module 2.3 on the high voltage side, the electrical/optical conversion module 2.5, and the photoelectric energy conversion module 2.6 are all located on the high voltage side and installed in an aluminum alloy transfer box. The digital optical signal of the digital voltage signal is transmitted to the local module 2.8 in the main control room on the low-voltage side through the signal optical fiber, converted into a digital electrical signal through the optical/electrical conversion module 2.10, and then passed through the signal processing circuit and the D/A conversion module 2.9 Restored to the analog signal of the phase voltage, the voltage signal is collected by the DAQ-2006 data acquisition card to the industrial computer.

The current signal and phase voltage signal of the UHV transmission line are collected to the industrial computer by the DAQ-2006 data acquisition card located in the main control room of the low voltage side. The DAQ-2006 data acquisition card is installed in the PCI slot of the industrial computer, and the industrial computer, UPS uninterruptible power supply, and two local modules 2.8 for demodulating the current signal and voltage signal are all installed in the standard industrial control cabinet. The industrial computer is equipped with corona loss monitoring software developed based on virtual instrument technology. Using the sine wave algorithm, the corona loss results can be calculated in real time for the collected voltage and current signals, and the monitored results can be automatically saved.

The measurement example of the present invention is as follows:

At present, this system has been applied to monitor the corona loss of the side phase and middle phase test line sections of the single-circuit test line section of the UHV AC test base of the State Grid Wuhan High Voltage Research Institute for a period of time. In the main control room, open the industrial control cabinet, turn on the power switch, the electronic current transformer and optical fiber transmission channel start to run, start the industrial control computer, run the software, enter the account name and password, log in and run the corona loss monitoring system. The voltage signal and current signal are photoelectrically converted by the remote module 2.2 on the high-voltage side, and converted into optical signals, which are transmitted to the main control room on the low-voltage side through optical cables, and demodulated and restored to analog signals of voltage signals and current signals by the local module 2.8. Collected by the DAQ-2006 synchronous data acquisition card, the system starts to monitor the voltage waveform and current waveform. The background program extracts the fundamental wave components of the voltage signal and current signal through digital filtering, moves the sampling point of the fundamental wave of the current signal, and digitally shifts the fundamental wave components of the current signal, thereby minimizing the inherent error of the system and improving the measurement accuracy of the system. For the fundamental wave components of the voltage signal and current signal, the corona loss value is calculated in real time by using the sine wave parameter method. The calculation method of the sine wave parameter method is as follows:

Suppose corona current i(t)=I _m sin(ωt+φ _i ), phase voltage u(t)=U _m sin(ωt+φ _i ), then current i(t) and voltage u(t) can be developed for

i(t)＝D ₀ sinωt+D ₁ cosωt (1)

u(t)＝C ₀ sinωt+C ₁ cosωt (2)

In the formula, D ₀ =I _m cosφ _i , D ₁ =I _m sinφ _i , C ₀ =U _m cosφu, C ₁ =U _m cosφ _u .

According to the orthogonality of trigonometric functions, the formulas for computing D ₀ , D ₁ , C ₀ , and C ₁ can be derived:

${\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}\underset{\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; T</span>}}{<span\; class="notranslate">\; \&Integral;</span>}}\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&omega;</span>}{\mathrm{<span\; class="notranslate">\; td</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

${\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}\underset{\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; T</span>}}{<span\; class="notranslate">\; \&Integral;</span>}}\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&omega;td</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

${\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}\underset{\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; T</span>}}{<span\; class="notranslate">\; \&Integral;</span>}}\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&omega;</span>}{\mathrm{<span\; class="notranslate">\; td</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

${\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}\underset{\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; T</span>}}{<span\; class="notranslate">\; \&Integral;</span>}}\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&omega;td</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>$

Therefore:

φ _i =tan ^-1 (D ₁ /D ₀ ), φ _u =tan ^-1 (C ₁ /C ₀ ) (7)

can be calculated

就可以实时计算出特高压输电线路电晕损失的结果。自动保存电晕损失监测结果，以便今后对特高压输电线路的电晕损失的规律作进一步的深入研究和分析。The effective value of the phase voltage and phase conductor current of the transmission line has been measured in real time by the program, and then according to the corona loss formula

The result of the corona loss of the UHV transmission line can be calculated in real time. Automatically save the corona loss monitoring results for further in-depth research and analysis on the law of corona loss of UHV transmission lines in the future.

From January 13 to January 15, 2008, the test base experienced two snowfalls, and the corona loss monitoring results at that time are shown in Figure 8.

Claims (3)

1. An electronic current transformer for UHV transmission lines, characterized in that: it includes a resistance sampling unit (2.1), a remote module (2.2), an optical fiber composite insulator (2.7) and a local module (2.8), and the resistance sampling unit (2.1) The remote module (2.2) is electrically connected, and the remote module (2.2) is optically connected to the local module (2.8) through an optical fiber composite insulator (2.7); The resistance sampling unit (2.1) comprises a front conductive copper rod (3.1), a copper foil (3.2), a circuit board (3.3), a precision non-inductive resistor (3.4) and a rear conductive copper rod (3.1) electrically connected in sequence; The remote module (2.2) includes an electrically connected high-voltage side A/D conversion module (2.3) and an electrical/optical conversion module (2.5), and the photoelectric energy conversion module (2.6) is connected to the high-voltage side A/D conversion module (2.3) respectively. ) is electrically connected to the electrical/optical conversion module (2.5); The local module (2.8) includes a signal processing circuit and a D/A conversion module (2.9), an optical/electrical conversion module (2.10), a laser (2.11), a power supply (2.12), and a driving circuit (2.13); the optical/electrical The conversion module (2.10) is electrically connected to the signal processing circuit and the D/A conversion module (2.9), the drive circuit (2.13) is electrically connected to the laser (2.11), and the power supply (2.12) is supplied to the signal processing circuit and the D/A conversion module (2.9 ), an optical/electrical conversion module (2.10), a drive circuit (2.13) and a laser (2.11) to provide electric energy; Both ends of the precision non-inductive resistor (3.4) in the resistance sampling unit (2.1) output voltage signals to the high-voltage-side A/D conversion module (2.3) in the remote module (2.2). 2. A UHV transmission line corona loss measurement device using the electronic current transformer for UHV transmission lines according to claim 1, characterized in that: it includes an electronic current transformer (1.3), a UHV capacitive Voltage transformer (1.4), iron core coil (1.9) for secondary voltage division and industrial computer; The electronic current transformer (1.3) includes a resistance sampling unit (2.1), a remote module (2.2), an optical fiber composite insulator (2.7) and a local module (2.8), and the resistance sampling unit (2.1) is electrically connected to the remote module (2.2). , the remote module (2.2) is optically connected to the local module (2.8) through an optical fiber composite insulator (2.7); the output of the local module (2.8) is connected to the DAQ-2006 data acquisition card of the industrial computer; The resistance sampling unit (2.1) and the remote module (2.2) of the electronic current transformer (1.3) are suspended at the beginning of the phase wire; The UHV capacitive voltage transformer (1.4) is installed at the outlet end of the bushing of the UHV transformer (1.1), the secondary winding terminal of the UHV capacitive voltage transformer (1.4) intermediate transformer and the iron core coil for secondary voltage division (1.9) Electrically connected, the output signal of the iron core coil (1.9) for secondary voltage division is used for electrical/optical conversion, and is transmitted to the local module (2.8) for voltage measurement with an optical cable, and then is used by the DAQ-2006 data acquisition card of the industrial computer collection. 3. The device for measuring corona loss of UHV transmission lines according to claim 2, characterized in that: the industrial computer is electrically connected to the wind speed sensor (1.5), the temperature and humidity sensor (1.6) and the instantaneous rain gauge (1.7).

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