CN104698265A - High-voltage direct current transmission line corona loss measurement system - Google Patents

Abstract

The invention provides a corona loss measurement system for a high-voltage direct current transmission line, which includes a corona current measurement unit, a high voltage measurement unit, and a corona loss comprehensive processing unit; and the corona loss comprehensive processing unit receives and calculates the corona current The corona current value measured by the measurement system and the voltage value measured by the high voltage measurement system are used to complete the calculation of the corona loss data. Compared with the prior art, the corona loss measurement system of the high-voltage direct current transmission line provided by the present invention, the corona current measurement unit in the measurement system is a split structure, which is easy to install and maintain on site; it is suitable for super/ultra-high voltage direct current Line, the measurement result of the measurement system is accurate, has strong resistance to electrical breakdown and is efficient and easy to use; and can operate stably for a long time in UHV DC environment and various harsh natural environmental conditions; for in-depth research on high-voltage DC line corona loss Effective and reliable technical means are provided.

Description

A Corona Loss Measurement System for HVDC Transmission Lines

technical field

The invention relates to a corona loss measurement system, in particular to a corona loss measurement system for a high-voltage direct current transmission line.

Background technique

In order to implement the national energy policy and ensure the comprehensive, coordinated, sustainable and healthy development of the power industry, the State Grid Corporation of China has proposed a major strategic measure to accelerate the development of AC and DC UHV power grids according to my country's national conditions. UHV transmission is developed on the basis of ultra-high voltage transmission, which can realize long-distance and large-capacity transmission of electric energy, and is suitable for the interconnection of large-scale power grids. Unlike UHV AC transmission, UHV DC transmission lines have lower cost and lower power loss, and are more suitable for ultra-long-distance large-capacity power transmission.

Among them, the research on corona loss of transmission lines is one of the key technologies of UHV DC power transmission and transformation projects, and the research on corona loss of transmission lines is of great significance to the economical operation of transmission lines. The research on corona loss measurement methods and measurement systems of EHV/UHV DC transmission lines is of great significance for the design and planning of UHV transmission lines, and for the study of the relationship between corona loss and electromagnetic environment, meteorological conditions, and circuit parameters.

At present, there are various methods such as bridge circuit method, coupled antenna method, and power meter method for the measurement of corona loss in HVDC transmission lines in China. It is difficult to achieve long-term online measurement, it is difficult to realize multi-point synchronous measurement, and it is impossible to measure the transient waveform of corona current.

At present, foreign studies on the corona effect of UHV DC lines are all done through corona cages and related tests on test line sections. The geographical and weather conditions of each country are different. Many countries have carried out mathematical statistics on a large number of test data and proposed empirical formulas suitable for the relevant parameters of the corona effect in their respective countries. However, due to the late start of UHV in my country, there is no effective corona effect test method. , the previous research work mainly focused on the simulation calculation of the corona effect, and in the wire selection, the wire splitting form was only selected according to the results calculated by foreign formulas, and a large number of corona effect tests were not carried out on various wires to verify . It is inappropriate to only rely on foreign empirical formulas to calculate the parameters related to the corona effect of conductors to guide the selection of UHV line conductors in my country. The reasons are: (1) The calculation results of corona effect-related calculation formulas in various countries are quite different and not uniform; (2) The structure and production process of transmission line conductors in different countries are not the same, and the prediction formulas of different countries are based on their respective countries. It is impossible to be applicable to all countries obtained from the test of transmission wires; (3) The climates of various countries are quite different, and the climate has a great influence on the corona loss of DC transmission lines, and the calculation of corona loss must indicate the climatic conditions.

Based on the above issues, my country has gradually established its own UHV test base in the field of UHV. In 2007, China built UHV DC corona cages and UHV AC corona cages and corresponding UHV test lines in Beijing UHV DC Test Base and Wuhan UHV AC Test Base respectively. On the UHV AC test line section of the State Grid Corporation of China, North China Electric Power University designed and developed an AC corona loss detection system; Measurement: the voltage is measured by the capacitive voltage transformer (CVT) in the UHV test base, and the high-precision small voltage transformer is used for secondary voltage division, which realizes the accurate and reliable measurement of the line voltage; the current and voltage signals are transmitted by optical fiber; Based on virtual instrument technology, high-precision multi-channel high-speed synchronous data acquisition card is used to synchronously collect corona current and voltage signals of UHV line segments, and the sine wave parameter method is used to calculate the power factor angle of voltage and current, and then calculate the corona loss value. However, on the one hand, the system is only used in UHV AC systems, not suitable for UHV DC transmission lines; on the other hand, due to the low sampling rate of the measurement system, the audible noise and radio interference caused by corona are caused by pulse current Generated, basically in the high-frequency band, so the system has little significance for the research of the source effect caused by the corona pulse current.

As EHV/UHV DC transmission lines are more and more widely used, how to design a corona loss measurement method with accurate measurement results, strong resistance to electrical breakdown, high efficiency and ease of use that is suitable for EH/UHV DC transmission lines system is a problem to be solved urgently by those skilled in the art.

Contents of the invention

In view of this, the present invention provides a corona loss measurement system for high-voltage direct current transmission lines. The corona current measurement unit in the measurement system is a split structure, which is easy to install and maintain on site; it is suitable for super/ultra-high voltage direct current lines, The measurement results of the measurement system are accurate, have strong anti-corona discharge performance, and are efficient and easy to use; and can operate stably for a long time in the UHV DC environment and various harsh natural environmental conditions; it provides a basis for in-depth research on the corona loss of high-voltage DC lines Effective and reliable technical means.

A high-voltage direct current transmission line corona loss measurement system, the measurement system includes a corona current measurement unit, a high voltage measurement unit and a corona loss comprehensive processing unit;

The corona current measurement unit adopts a distributed structure, and the input side of the corona current measurement unit is arranged on the high-voltage direct current transmission line;

The input side of the high voltage measurement unit is connected to the high voltage direct current transmission line;

Both the output sides of the corona current measurement unit and the high voltage measurement unit are connected to the corona loss comprehensive processing unit;

The corona loss comprehensive processing unit receives and calculates and processes the corona current value measured by the corona current measurement system and the voltage value measured by the high voltage measurement system.

Preferably, the corona current measurement unit includes a corona current signal sampling module, a corona current data measurement module and a power supply module connected in sequence;

The corona current signal sampling module is arranged on the high voltage direct current transmission line.

Preferably, the corona current signal sampling module includes a wave trap and a sampling resistance sensor sequentially connected in series on the high-voltage direct current transmission line;

The corona current data measurement module includes a filter, an AD converter 1 and a central control unit 1 connected in series in sequence;

The power supply module is provided with an energy control panel and a storage battery;

The sampling resistance sensor is connected in series with the filter;

The corona current signal collected by the corona current signal sampling module is converted into a digital signal by the AD converter 1, and the central control unit 1 performs preliminary data processing on the digital signal in a window average mode to obtain the current average value.

Preferably, the power supply module and the corona current data measurement module are respectively placed in different metal cylinders.

Preferably, the high voltage measurement unit includes a high voltage generator and a high voltage measurement module respectively connected to the high voltage direct current transmission line.

Preferably, the high voltage measurement module includes a DC voltage divider, an AD converter 2 and a central control unit 2 connected in series in sequence;

The input side of the DC voltage divider is connected to the high voltage DC transmission line;

The output side of the DC voltage divider is connected to the AD converter 2;

The AD converter 2 directly converts the voltage analog signal collected by the DC voltage divider into a digital signal, and the central control unit 2 performs window-average processing on the digital signal to obtain a voltage value.

Preferably, a protection circuit 1 is connected between the sampling resistance sensor and the filter;

A protection circuit 2 is connected to the DC voltage divider.

Preferably, the central control unit 1 and the central control unit 2 are equipped with USB modules, and the central control unit 1 and the central control unit 2 communicate with the photoelectric transmission device 1 and the photoelectric transmission device 1 respectively through the USB modules on themselves. Transmission device two interacts.

Preferably, the corona loss comprehensive processing unit includes a host computer and a software comprehensive processing module;

The software comprehensive processing module is provided with a man-machine interface and a database;

Both the photoelectric transmission device 1 and the photoelectric transmission device 2 are connected to the corona loss comprehensive processing unit through an optical fiber;

The corona loss comprehensive processing unit completes the calculation of corona loss data according to the received corona current average value and voltage value, displays the result on the man-machine interface, and saves the data to the database.

Preferably, the AD converter 1 and the AD converter 2 are integral high-precision AD converters.

It can be seen from the above technical scheme that a corona loss measurement system for HVDC transmission lines provided by the present invention includes a corona current measurement unit, a high voltage measurement unit and a corona loss comprehensive processing unit; and the corona loss comprehensive processing unit The unit receives and calculates and processes the corona current value measured by the corona current measurement system and the voltage value measured by the high voltage measurement system, and completes the calculation of corona loss data. Compared with the prior art, the corona loss measurement system of the high-voltage direct current transmission line provided by the present invention, the corona current measurement unit in the measurement system is a split structure, which is easy to install and maintain on site; it is suitable for super/ultra-high voltage direct current Line, the measurement result of the measurement system is accurate, has strong resistance to electrical breakdown and is efficient and easy to use; and it can operate stably for a long time in UHV DC environment and various harsh natural environmental conditions; for in-depth research on high-voltage DC line corona loss Effective and reliable technical means are provided.

Compared with the closest prior art, the technical solution provided by the present invention has the following excellent effects:

1. In the technical solution provided by the present invention, the corona current measurement unit, the corona loss comprehensive processing unit and the high voltage measurement unit are placed separately in the current measurement system, and the corona current measurement unit adopts a split design, which is easy to install on site And maintenance, simplifies the installation and maintenance process of the measuring device, saving time and money costs.

2. In the technical solution provided by the present invention, the measurement system includes a corona current measurement unit, a high voltage measurement unit, and a corona loss comprehensive processing unit; and the corona loss comprehensive processing unit receives and calculates and processes the corona current measurement system The measured corona current value and the voltage value measured by the high-voltage measurement system; make the measurement system suitable for super/ultra-high voltage DC lines with accurate measurement results, strong resistance to electrical breakdown, and high efficiency and ease of use; and It can operate stably for a long time in the UHV DC environment and various harsh natural environmental conditions; it provides an effective and reliable technical means for in-depth research on the corona loss of high-voltage DC lines.

3. In the technical solution provided by the present invention, the power supply module and the corona current measurement module are both inside the metal cylinder, so that the power supply system and the measurement system will not be subject to electromagnetic interference in the UHV environment, and there is no corona discharge itself ; Ensure the accuracy of the measurement, while improving the reliability of the measurement system.

4. In the technical solution provided by the present invention, the system adopts an integral AD converter, which has a simple structure and is not easily affected by the UHV DC electromagnetic environment; the reliability and effectiveness of the measurement process are improved.

5. In the technical solution provided by the present invention, the setting of the central control unit makes the data of the collected voltage value and corona current value undergo preliminary processing, so the demand for data transmission is low, that is, higher stability and low speed can be used. The transmission system is not easily affected by the external complex electromagnetic environment, which improves the reliability and effectiveness of the measurement process.

6. In the technical solution provided by the present invention, the use of man-machine interface and database in the corona loss comprehensive processing system can display data and save the data in the database for further processing and analysis, so that the measurement results can be preserved. Improves the efficiency of further processing of data afterwards.

7. The technical solution provided by the present invention is widely used and has significant social and economic benefits.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is a structural schematic diagram of a corona loss measurement system for HVDC transmission lines according to the present invention.

Fig. 2 is a structural schematic diagram of the corona current measuring unit of the measuring system of the present invention.

Fig. 3 is a schematic structural diagram of the high voltage measurement unit of the measurement system of the present invention.

Fig. 4 is a schematic structural view of the corona loss comprehensive processing unit of the measurement system of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts fall within the protection scope of the present invention.

As shown in Figure 1, the present invention provides a corona loss measurement system for HVDC transmission lines, including a corona current measurement unit, a high voltage measurement unit and a corona loss comprehensive processing unit;

The corona current measurement unit adopts a distributed structure, and the input side of the corona current measurement unit is set on the high-voltage direct current transmission line;

The input side of the high voltage measurement unit is connected to the high voltage direct current transmission line;

The output sides of the corona current measurement unit and the high voltage measurement unit are connected to the corona loss comprehensive processing unit;

The corona loss comprehensive processing unit receives and calculates and processes the corona current value measured by the corona current measurement system and the voltage value measured by the high voltage measurement system.

Wherein, the corona current measurement unit is used to measure the corona current value in the ultra/ultra-high voltage transmission line, and adopts a split design; the high voltage measurement unit is used to measure the conductor voltage of the ultra/ultra high voltage line; the corona loss comprehensive The processing unit is used for synthesizing the corona current value measured by the corona current measuring unit and the voltage value measured by the high voltage measuring unit, so as to perform calculation processing and complete the measurement of the line corona loss.

As shown in Figure 2, the corona current measurement unit includes a corona current signal sampling module, a corona current data measurement module and a power supply module connected in sequence;

The corona current signal sampling module is set on the high voltage direct current transmission line.

Among them, the corona current signal sampling module includes a wave trap and a sampling resistance sensor connected in series on the high-voltage direct current transmission line;

The corona current data measurement module includes a filter connected in series, an AD converter 1 and a central control unit 1;

The power supply module is equipped with an energy control board and a battery; the high-voltage side power supply module uses a large-capacity battery; the design adopts a split design with the high-voltage side corona current signal sampling module and the high-voltage side corona current data measurement module, which is easy to Installation and replacement, the modular design is easier to commercialize. The high-voltage side corona current signal sampling module is connected to the signal input connector of the high-voltage side corona current data measurement module through a shielded twisted pair; the power output of the high-voltage side power supply module is connected to the power input connector of the high-voltage side corona current data measurement module; The optical fiber connector of the corona current data measurement module on the high-voltage side is connected to the outdoor optical fiber, and is connected to the corona loss comprehensive processing unit through the outdoor optical fiber.

The sampling resistance sensor is connected in series with the filter; the sampling resistance sensor is connected in series to the transmission line to collect the corona current signal; the wave trap is connected in series at the front end of the sampling resistance sensor, and the filter circuit is connected in series behind the sampling resistance sensor to jointly complete the filtering work of unnecessary interference ; The protection circuit can protect the system from being damaged by instantaneous high voltage.

The corona current signal collected by the corona current signal sampling module is converted into a digital signal by the AD converter 1, and the central control unit 1 performs preliminary data processing on the digital signal in a window average mode to obtain the current average value.

The power supply module and the corona current data measurement module are respectively placed in different metal cylinders.

As shown in Fig. 3, the high-voltage measurement unit includes a high-voltage generator and a high-voltage measurement module respectively connected to the high-voltage direct current transmission line. The high-voltage measurement unit can be powered by mains, which is easy to use.

The high voltage measurement module includes a DC voltage divider, an AD converter 2 and a central control unit 2 connected in series in sequence;

The high voltage measurement unit adopts a DC voltage divider mode, the input of the DC voltage divider is the voltage level input on the line, the output of the DC voltage divider is connected to the sampling circuit, and the protection circuit ensures that the sampling circuit will not be damaged due to sudden high voltage pulses. while damaged,

The input side of the DC voltage divider is connected to the high-voltage DC transmission line;

The output side of the DC voltage divider is connected to the second AD converter;

The AD converter 2 directly converts the voltage analog signal collected by the DC voltage divider into a digital signal, and the central control unit 2 performs window-average processing on the digital signal to obtain a voltage value.

Wherein, a protection circuit 1 is connected between the sampling resistance sensor and the filter;

A protection circuit 2 is connected to the DC voltage divider.

The central control unit 1 and the central control unit 2 are both provided with USB modules, and the central control unit 1 and the central control unit 2 interact with the photoelectric transmission device 1 and the photoelectric transmission device 2 respectively through their own USB modules.

Among them, the data transmitted by the photoelectric transmission device is the averaged data of the window, and the amount of data is much smaller than the original data collected by the AD converter, and the initial high sampling rate can also ensure the data accuracy. And the average length of the window can be modified according to the accuracy requirements and the design of the corona loss system, and the accuracy and the amount of transmitted data can be adjusted.

As shown in Figure 4, the corona loss comprehensive processing unit includes a host computer and a software comprehensive processing module;

The software comprehensive processing module has a man-machine interface and a database;

Both the photoelectric transmission device 1 and the photoelectric transmission device 2 are connected to the corona loss comprehensive processing unit through an optical fiber;

The corona loss comprehensive processing unit completes the calculation of corona loss data according to the received corona current average value and voltage value, displays the result on the man-machine interface, and saves the data to the database.

The upper computer is connected with the photoelectric transmission device 2 of the high voltage measurement unit and the photoelectric transmission device 1 of the corona current measurement unit through the USB module, mainly for receiving digital quantities, receiving high voltage measurement data and corona current average data. The software comprehensive processing system is mainly to further process the received voltage data and current data, complete the calculation of corona loss data, and has a friendly man-machine interface, which can display the data and save the data in the database for further processing and analysis .

Among them, the AD converter 1 and the AD converter 2 are integral high-precision AD converters.

The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art can still modify or equivalently replace the specific embodiments of the present invention. , and any modifications or equivalent replacements that do not deviate from the spirit and scope of the present invention are all within the protection scope of the claims of the pending application of the present invention.

Claims (10)

1. a HVDC (High Voltage Direct Current) transmission line corona loss measuring system, is characterized in that, described measuring system comprises corona current measuring unit, high voltage measuring unit and corona loss overall treatment unit;

Described corona current measuring unit adopts distributed frame, and the input side of described corona current measuring unit is arranged in described HVDC (High Voltage Direct Current) transmission line;

The input side of described high voltage measuring unit is connected with HVDC (High Voltage Direct Current) transmission line;

Described corona current measuring unit is all connected with described corona loss overall treatment unit with the outgoing side of described high voltage measuring unit;

Described corona loss overall treatment unit receives and the corona current value that described in computing, corona current measuring unit records and the magnitude of voltage that described high voltage measuring unit records.

2. measuring system as claimed in claim 1, it is characterized in that, described corona current measuring unit comprises the corona current signal sampling module, corona current data measurement module and the supply module that connect successively;

Described corona current signal sampling module installation is in described HVDC (High Voltage Direct Current) transmission line.

3. measuring system as claimed in claim 2, is characterized in that, described corona current signal sampling module comprises and is connected on trap in described HVDC (High Voltage Direct Current) transmission line and sampling resistor sensor successively;

Described corona current data measurement module comprises wave filter, AD converter one and the central control unit one of connecting successively;

Energy control plate and accumulator is provided with in described supply module;

Described sampling resistor sensor and described filters in series;

Described corona current signal sampling module acquires to corona current signal be converted into digital signal by described AD converter one, central control unit one carries out preliminary data process with forms average mode to this digital signal, obtain current average.

4. measuring system as claimed in claim 3, it is characterized in that, described supply module and described corona current data measurement module are placed in different metallic cylinder respectively.

5. the measuring system as described in claim 3 or 4, is characterized in that, described high voltage measuring unit comprises the high pressure generator and high voltage measuring module that are connected with described HVDC (High Voltage Direct Current) transmission line respectively.

6. measuring system as claimed in claim 5, it is characterized in that, described high voltage measuring module comprises divider, AD converter two and the central control unit two of connecting successively;

The input side of described divider is connected with described HVDC (High Voltage Direct Current) transmission line;

The outgoing side of described divider is connected with described AD converter two;

The voltage analog signal that described divider collects is converted into digital signal by described AD converter two, and described central control unit two carries out forms average treatment to this digital signal, obtains magnitude of voltage.

7. measuring system as claimed in claim 6, is characterized in that,

Protection circuit one is connected with between described sampling resistor sensor and described wave filter;

Described divider is connected with protection circuit two.

8. measuring system as claimed in claims 6 or 7, is characterized in that,

Described central control unit one and described central control unit two are equipped with USB module, described central control unit one and described central control unit two by the USB module on self respectively with opto-electrical transmitting device one and opto-electrical transmitting device two mutual.

9. measuring system as claimed in claim 8, is characterized in that,

Described corona loss overall treatment unit comprises host computer and software synthesis processing module;

Described software synthesis processing module is provided with man-machine interface and database;

Described opto-electrical transmitting device one and described opto-electrical transmitting device two are all connected with described corona loss overall treatment unit by optical fiber;

Described corona loss overall treatment unit completes the calculating of corona loss data according to the corona current mean value received and magnitude of voltage, result be presented in described man-machine interface, and data are saved in described database.

10. the measuring system as described in any one of claim 6 to 9, is characterized in that, described AD converter one and AD converter two are integral form high-precision AD converter.