CN201886113U - Pilot-frequency and high-current multifunctional grounding parameter testing system based on variable frequency power supply - Google Patents

Pilot-frequency and high-current multifunctional grounding parameter testing system based on variable frequency power supply Download PDF

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Publication number
CN201886113U
CN201886113U CN2010206583665U CN201020658366U CN201886113U CN 201886113 U CN201886113 U CN 201886113U CN 2010206583665 U CN2010206583665 U CN 2010206583665U CN 201020658366 U CN201020658366 U CN 201020658366U CN 201886113 U CN201886113 U CN 201886113U
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transformer
frequency
variable
frequency power
output
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CN2010206583665U
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Chinese (zh)
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许安
葛凯
崔涛
曾宏
濮峻嵩
吴驰
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四川电力试验研究院
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Abstract

The utility model relates to a pilot-frequency and high-current multifunctional grounding parameter testing system based on a variable frequency power supply, belonging to a testing device for the grounding parameters of a transformer substation ground screen. The pilot-frequency and high-current multifunctional grounding parameter testing system mainly consists of a variable frequency power supply unit and a step-up transformer unit. The variable frequency power supply unit consists of two pushoff amplification type variable frequency power supplies which are connected in parallel, the rating input voltage of each variable frequency power supply which is 50Hz three-phase alternating current is 380+/-10%, the output sine wave is 0-350V and is continuously adjustable, and the output frequency is 20-300Hz and is continuously adjustable. The step-up transformer unit consists of a step-up transformer, the primary coil of the step-up transformer is connected with two output ends of the variable power supply unit, the secondary coil of the step-up transformer is connected with the transformer substation ground screen, and for the step-up transformer, the frequency set capacity is 15kVA, the output voltage is 200V, 400V, 600V, 800V or 1000V, and the preset frequency is 20-300Hz. The pilot-frequency and high-current multifunctional grounding parameter testing system based on the variable frequency power supply has the characteristics of strong antijamming capacity and high measurement accuracy.

Description

The multifunctional grounded parameter test system of the big electric current of alien frequencies based on variable-frequency power sources

Technical field

The utility model relates to a kind of proving installation of earthed system ground connection parameter, particularly based on the multifunctional grounded parameter test system of the big electric current of alien frequencies of variable-frequency power sources technology in parallel, is applied to the parameter testing of the large-scale earth mat ground connection of electric system.

Background technology

The earth mat of electric power system power plant, transformer station has very important effect to the safe and stable operation of electric system.When system is short-circuited fault, the powerful short-circuit current earth mat of flowing through makes the earth mat earth potential raise, as have that the earth mat impedance ground is big, earth potential irrational distribution or have problem such as burn into broken string, earthy rising may jeopardize equipment and personnel's personal safety.

In the large-scale earth mat ground connection of electric system parameter measurement process, the power frequency interference signals influence that produces when preventing operation of power networks improves the accuracy of measuring, power industry standard rules regulation, and the test current of the big current method of power frequency must not be less than 30 amperes.Thereby problems such as testing equipment heaviness, test process complexity, testing crew working strength are big, the test period is long appear.

Though the instrument of alien frequencies method test ground connection parameter commonly used in the market has advantages such as antijamming capability is strong, test data stable, testing equipment is light, its measuring current is low can't accurately measure parameters such as place surface potential gradient, contact potential difference, step voltage difference again.

The utility model content

The purpose of this utility model is to overcome the deficiency that prior art exists, and provides the big electric current of the alien frequencies based on variable-frequency power sources that a kind of antijamming capability is strong, measuring accuracy is high multifunctional grounded parameter test system.

The purpose of this utility model is achieved through the following technical solutions: the multifunctional grounded parameter test system of the big electric current of a kind of alien frequencies based on variable-frequency power sources, comprise, from the treated frequency conversion meter that obtains the impedance ground value of electric current, the voltage signal of substation ground network collection, also have variable-frequency power sources unit and step-up transformer unit; Wherein, variable-frequency power sources unit: push off the amplifying type variable-frequency power sources by two 15kW and compose in parallel, the specified input voltage of this every variable-frequency power sources is 380V ± 10%, 50Hz three-phase alternating current, and sine wave output 0~350V is adjustable continuously, and output frequency is that 20~300Hz is adjustable continuously;

The step-up transformer unit: be made up of a step-up transformer, the primary coil of step-up transformer is connected with two output terminals of variable-frequency power sources unit, and the secondary coil of this step-up transformer is connected with substation ground network; The frequency constant volume of this step-up transformer is 15kVA, and output voltage is 200V, 400V, 600V, 800V or 1000V, and preset frequency is 20~300Hz.

Above-mentioned frequency conversion meter is connected communication and control module and display unit in turn by signals collecting and processing unit and forms, signals collecting and processing unit are made up of voltage transformer (VT), current transformer and amplification filtering treatment circuit again, and the two signal output part of voltage transformer (VT) summation current transformer connects the amplification filtering treatment circuit.

The beneficial effects of the utility model are:

This device can be realized large-scale earth mat place surface potential gradient, contact potential difference, poor, the isoparametric test of impedance ground of step voltage, avoids the influence of power frequency interference signals.What inject earth mat is non-power-frequency current signal (frequency near power frequency, but differ from power frequency), and antijamming capability is strong, measuring accuracy is high, and is high-current test.Frequency-selecting is measured and the advantage of big electric current owing to have both, and measurement data is reliable and stable, and test result more can help the optimal design of the large-scale earth mat of electric system, guarantees Operation of Electric Systems safety.

The utility model people utilize this cover system right respectively ± 500kV Deyang current conversion station, 110kV nationality field substation grounding device measure, on-the-spot test is the result show, this complete equipment can be finished earthing device accurately and quickly and measure, and can satisfy the measurement of power frequency parameters such as large-scale earth mat impedance ground and step voltage, contact electricity, surface potential gradient simultaneously, solved the difficult problem that large-scale earth mat is measured.

Description of drawings

Fig. 1 is the annexation synoptic diagram of the utility model system and substation ground network.

Fig. 2 is the utility model system hardware block diagram.

Fig. 3 is two shown in Figure 2 and pushes off the formula variable-frequency power sources and be connected in parallel and concern synoptic diagram.

Fig. 4 is frequency conversion meter (being that ammeter is measured in a frequency conversion) AC sampling The general frame.

Embodiment

The core of the multifunctional grounded impedance test system of the big electric current of the utility model alien frequencies comprises variable-frequency power sources, signals collecting and data processing two large divisions, as Fig. 1.

Wherein, the variable-frequency power sources part is recommended the amplifying type variable-frequency power sources by 2 15kW and is composed in parallel (referring to Fig. 3), can realize that sine wave output 0~350V is adjustable continuously, output frequency is that 20~300Hz is adjustable continuously, and be furnished with two step-up transformers, the variable-frequency power sources output voltage can be raised to suitable voltage and inject earth mat.

Signals collecting, data processing and Presentation Function are realized that by HVXP frequency-selecting voltage, reometer this table antijamming capability is strong, can measure voltage, the current signal of 40~65Hz.The hardware design of the multifunctional grounded impedance test system of the big electric current of alien frequencies as shown in Figure 2.

1) the HVFP type is recommended the technical parameter and the characteristic of amplifying type variable-frequency power sources:

The multifunctional grounded impedance test system of the big electric current of alien frequencies adopts two and recommends the parallel connection of amplifying type variable-frequency power sources as power source, and parallel circuit as shown in Figure 3.The output capacity that separate unit is recommended the amplifying type variable-frequency power sources is 15kW, and important technological parameters is as follows:

Specified input voltage: three-phase alternating current 380V ± 10%, 50Hz;

Rated output capacity: 30kW;

Output voltage: single-phase, sinusoidal wave 0~350V is adjustable continuously;

Output current: 0~85A;

Output voltage instability :≤1%;

Output frequency: 20~300Hz is adjustable continuously;

Output frequency is regulated fineness: 0.1Hz;

Output frequency instability :≤0.1%;

Output waveform is a standard sine wave: irregularity of wave form≤1%;

Local interference discharge capacity:<10pc;

The test duration setting range: 0~99 minute, precision 0.1 second;

Dielectric level: the input, lead-out terminal over the ground 〉=3kV/AC/1min;

Variable-frequency power sources allows working time: output rating allows operation 60min down;

Allow temperature rise: under nominal load, continuous working 60min, air outlet temperature rise≤45K;

The type of cooling: forced air cooling;

Separate unit weight: 48kg.

Recommending the amplifying type frequency conversion for 2 only need connect output terminal is corresponding when in parallel, power supply capacity can be improved 2 times, do not need complicated wiring just can realize super high power output, and can realize that sine wave output 0~350V is adjustable continuously, output frequency is that 20~300Hz is adjustable continuously.In use, the signal of the frequency changing power device unit that only each need be connected in parallel connects with long-range control box by optical fiber, just can easily test, and is easy and simple to handle.The parallel connection of employing frequency changing power device makes things convenient for the maintenance of equipment, does not need to safeguard the equipment of a ultra-large volume, carries out but equipment is divided into two separate units, has solved the difficult problem in the super high power frequency changing power device production run, improves reliability.In addition, each frequency changing power device in parallel unit can independently become a variable-frequency power sources, is equivalent to two and overlaps independently power supply, and each frequency changing power device in parallel unit all keeps the independent protective device, can protect test specimen and equipment personal security fast and accurately.

2) technical parameter of HVJDB step-up transformer and characteristic:

Frequency conversion voltage is exported by bridge amplification circuit, and continuous by the low pressure end of step-up transformer, the high-pressure side of step-up transformer links to each other with the test loop, selects suitable output voltage to inject earth mat.

The step-up transformer structure is that single-phase dry type is self cooling.Be equipped with the electrostatic screening layer between high and low pressure winding and iron core, have only the contact of magnetic between the high-low pressure winding, do not have the contact of electricity,, can be used as isolating transformer again both as step-up transformer; Built-in over-voltage protective prevents to puncture counterattack.Exciting transformer has the carrying handle that bears its general assembly (TW), the connection copper busbar when providing the high pressure winding to be used in combination mutually.The single transformer rated capacity is 15kVA, and at present, this cover earth mat test macro is furnished with two, two transformers can in parallel be exported, the variable-frequency power sources output voltage can be raised to suitable voltage, inject earth mat, as the power source of ground network ground resistance test, step voltage test, the test of shunting situation.The single transformer technical parameter is as follows:

Rated capacity: 15kVA;

The number of phases: single-phase;

Specified input voltage: double winding, 2 * 350V, but connection in series-parallel is used;

Output voltage: 200V, 400V, 600V, 800V, 1000V (each winding is full capacity output);

Outlet method: input, output winding are all drawn at the transformer top;

Rated frequency: 20~300Hz;

Dielectric level: winding is 2kV/1min over the ground;

Partial discharge quantity :≤10pC;

Noise level :≤55dB;

The type of cooling: ONAN;

Temperature rise behind the continuous operation 60min under the rated capacity: less than 65 ℃;

Allow working time: output-current rating allows operation 60min down;

Weight: 180kg/ platform;

3) development of frequency conversion meter:

Compare with traditional metering system, frequency variation method is measured earthing device tangible advantage, and the good reproducibility of measurement has been eliminated the influence of accidentalia, can effectively eliminate undesired signal.If undesired signal is analyzed, be not difficult to find that the main concentration of energy of undesired signal is at power frequency and odd number frequency multiplication place thereof that the interfering energy of other frequency bands is less.As if stray current in the ground that can effectively avoid power frequency and odd harmonic frequencies place thereof, on other frequency, carry out the measurement of stake resistance, interference components will reduce greatly.

In this project, the researchist has successfully developed high power frequency conversion power supply, can inject frequency conversion voltage, current signal to substation ground network, therefore, research and develop out the measurement instrument that a cover receives frequency variation signal and can accurately measure its amplitude and phase place, become the technical matters that this project must solve.

The technical parameter of A, frequency conversion meter and test result:

The impedance ground frequency conversion meter of this project research and development has frequency-selecting voltage measurement function, can measure the voltage signal of 45~55Hz; Adopt the frequency conversion Anti-Jamming Technique, based on Fourier transform and spectrum analysis technique, measuring the frequency-selecting bandwidth can be narrow to 0.1Hz, can guarantee the pure property of survey frequency, effectively shielding power frequency and harmonic interference signal have very strong antijamming capability, simultaneously the external impressed current sensor, can realize the frequency-selecting current measurement, important technological parameters is as follows:

Voltage measurement scope: 1mV~50V;

Ultimate resolution: 0.01mV;

Accuracy of measurement: general mode ± (5%+2 word of reading *);

Degree of depth immunity mode ± (5%+2 word of reading *);

Survey frequency: general mode 45~55Hz, 0.1Hz step pitch;

Measure bandwidth: the narrowest 0.1Hz has 0.1,0.25,0.5Hz measures bandwidth for three kinds;

Jam-to-signal: general mode: 10: 1;

Degree of depth immunity mode: 100: 1, anti-jam frequency 50Hz;

Battery working time: about 8 hours;

Charge power supply: AC220V ± 10%, 50Hz;

Instruments weight: 3kg

For the precision to the frequency conversion meter developed detects, adopted standard signal generation source to calibrate inspection, this measurement result is shown in following table 1~table 3:

Table 1 measuring voltage accuracy detection:

Table 2 is measured current precision and is detected:

Table 3 measuring voltage, current phase angle accuracy detection:

Above detection data show, the frequency conversion meter of this project research and development in its range ability to the measuring accuracy error control of electric current and voltage and phase place in 5%, the relative error that has reached the measurement instrument of national relevant rules regulation will be 5% with interior standard.

The principle of work of B frequency conversion meter:

The frequency conversion meter is connected communication and control module and display unit in turn by signals collecting and processing unit and forms, signals collecting and processing unit are made up of voltage transformer (VT), current transformer and amplification filtering treatment circuit again, and the two signal output part of voltage transformer (VT) summation current transformer connects the amplification filtering treatment circuit.As shown in Figure 4, its principle of work is as follows:

Variable-frequency power sources is by injecting the sine ac power supply of 45~55Hz frequency range to earth mat, the electric current that the frequency conversion meter obtains from earthed system to be measured by signal acquisition module, voltage signal, through voltage transformer (VT) (PT), current transformer (CT) become 1-2mA current signal ,-voltage signal of 5-+5V, because the frequency of variable-frequency power sources can change arbitrarily, so the frequency conversion meter also need be realized manual ringing frequency smooth change.The same with numerous intelligent measure equipment, processing module is the hinge of the commander and the maincenter of processing, processing module will collect electric current, voltage signal amplifies (amplifying as adopting integrated operational amplifier) back and carrying out active power filtering, suppressing the power frequency of measure field disturbs, again filtered signal is adjusted, to reach the manageable range of signal of A/D module, after treating that power supply signal is stable, start A/D, carry out quick sampling, the amplitude and the phase place of signal are analyzed, extract resistive and perceptual weight, and remove the influence of mutual inductance, obtain the impedance ground value.

Communication and control module finish host computer and slave computer ask communicate by letter, data and duty that slave computer is collected are sent to host computer, the steering order of host computer is reached slave computer, control module by the TMS320VC5509A chip as primary processor, interior band 16 RAM of 128K and 16 ROM of 32K, realize the control of frequency conversion meter, finish functions such as warning and man-machine communication, and the final data output that obtains is presented on the liquid crystal display by communication and control module.By collaborative work, just can be grounded the automatic measurement of impedance with top.

The frequency conversion meter is connected communication and control module and display unit respectively by signals collecting and processing unit and forms.

Claims (2)

1. multifunctional grounded parameter test system of the big electric current of the alien frequencies based on variable-frequency power sources, comprise, from the treated frequency conversion meter that obtains the impedance ground value of electric current, the voltage signal of substation ground network collection, it is characterized in that: also have variable-frequency power sources unit and step-up transformer unit; Wherein, variable-frequency power sources unit: push off the amplifying type variable-frequency power sources by two 15kW and compose in parallel, the specified input voltage of this every variable-frequency power sources is 380V ± 10%, 50Hz three-phase alternating current, and sine wave output 0~350V is adjustable continuously, and output frequency is that 20~300Hz is adjustable continuously;
The step-up transformer unit: be made up of a step-up transformer, the primary coil of step-up transformer is connected with two output terminals of variable-frequency power sources unit, and the secondary coil of this step-up transformer is connected with substation ground network; The frequency constant volume of this step-up transformer is 15kVA, and output voltage is 200V, 400V, 600V, 800V or 1000V, and preset frequency is 20~300Hz.
2. the multifunctional grounded parameter test system of the big electric current of the alien frequencies of opportunity variable-frequency power sources according to claim 1, feature is: described frequency conversion meter is connected communication and control module and display unit in turn by signals collecting and processing unit and forms, signals collecting and processing unit are made up of voltage transformer (VT), current transformer and amplification filtering treatment circuit again, and the two signal output part of voltage transformer (VT) summation current transformer connects the amplification filtering treatment circuit.
CN2010206583665U 2010-12-14 2010-12-14 Pilot-frequency and high-current multifunctional grounding parameter testing system based on variable frequency power supply CN201886113U (en)

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102087331A (en) * 2010-12-14 2011-06-08 四川电力试验研究院 Pilot frequency heavy-current multifunctional grounding parameter testing system based on variable frequency power supply
CN102540013A (en) * 2011-12-27 2012-07-04 广东电网公司韶关供电局 Transformer substation grounding network frequency response test device
CN102628890A (en) * 2012-04-19 2012-08-08 李景禄 Intelligent grounding safety parameter monitoring method and device
CN103197133A (en) * 2013-03-26 2013-07-10 广东电网公司电力科学研究院 Large earth screen shunt vector quantity measurement method based on wireless transmission
CN103837775A (en) * 2014-03-17 2014-06-04 国家电网公司 Grounding grid corrosion diagnostic method and device
CN104777390A (en) * 2015-05-04 2015-07-15 山东达顺电子科技有限公司 Pilot frequency testing device for power-frequency parameters of line

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102087331A (en) * 2010-12-14 2011-06-08 四川电力试验研究院 Pilot frequency heavy-current multifunctional grounding parameter testing system based on variable frequency power supply
CN102540013A (en) * 2011-12-27 2012-07-04 广东电网公司韶关供电局 Transformer substation grounding network frequency response test device
CN102628890A (en) * 2012-04-19 2012-08-08 李景禄 Intelligent grounding safety parameter monitoring method and device
CN102628890B (en) * 2012-04-19 2014-12-03 李景禄 Intelligent grounding safety parameter monitoring method and device
CN103197133A (en) * 2013-03-26 2013-07-10 广东电网公司电力科学研究院 Large earth screen shunt vector quantity measurement method based on wireless transmission
CN103197133B (en) * 2013-03-26 2015-09-16 广东电网公司电力科学研究院 A kind of shunting of the large ground network based on wireless transmission vector quantity measurement method
CN103837775A (en) * 2014-03-17 2014-06-04 国家电网公司 Grounding grid corrosion diagnostic method and device
CN104777390A (en) * 2015-05-04 2015-07-15 山东达顺电子科技有限公司 Pilot frequency testing device for power-frequency parameters of line

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