CN102253257B - Integrated standard device for field calibration of extra/ultra high voltage capacitor voltage transformer (CVT) - Google Patents

Abstract

The invention provides an integrated standard device for field calibration of an extra/ultra high voltage capacitor voltage transformer (CVT). The device comprises a test power supply, a test lifting platform, a standard appliance, a measuring instrument and a vehicle platform, wherein the test power supply comprises cascade upper and lower level test transformers, a secondary compensating reactor and a voltage regulator; the standard appliance comprises cascade upper and lower level standard voltage transformers and a high voltage isolated transformer; the test lifting platform comprises a base, transmission mechanisms and insulating support members; the measuring instrument comprises a transformer calibrator and load boxes; all the equipment is fixedly installed on the vehicle platform;and the test lifting platform can lift in the vertical direction. The upper and lower level standard voltage transformers in the standard device can troubleshoot the standard device by way of mutual calibration in the field and complete field calibration of the extra/ultra high voltage CVT, without unloading.

Description

Integrated standard device for on-site verification of EHV/UHV CVT

technical field

The present invention relates to an integrated standard device for on-site verification of CVT, which belongs to the field of calibration, verification and detection of electric equipment, and in particular to an integrated standard device for on-site verification of super/ultra-high voltage CVT.

Background technique

With the rapid development of my country's power grid technology, the focus of my country's power grid construction will shift to large-scale, long-distance UHV backbone networks and smart grid construction based on this. Capacitor Voltage Transformer (CVT, Capacitor Voltage Transformer) is an important electrical equipment in the power grid. It is mainly composed of a capacitor voltage divider and a medium-voltage transformer. The transformer is composed of a transformer installed in a sealed oil tank, a compensation reactor and a damping device. The damping device is used to suppress resonance, and the damping device is composed of a resistor and a reactor. In recent years, with the continuous reform of the power industry, power generation and transmission and distribution companies operate separately, and the role of CVT in gateway measurement has become prominent. In order to ensure fairness, accuracy and regulation of electric energy measurement, the interests of power generation, transmission and power supply have been clarified And guarantee, in accordance with the relevant provisions of my country's metrology law ("GB/T4703-2001 Capacitive Voltage Transformer", "JJG1021-2007 Power Transformer Verification Regulations"), the transformer must be regularly calibrated on-site. At present, for the 220kV ~ 500kV CVT that has been installed or put into operation, the unloading on-site verification method is basically adopted, that is, the test power supply, standard appliances and measuring instruments are transported to the site, and then re-unloaded, assembled and then calibrated. However, because this method has to go through a series of cumbersome steps of unloading-assembly-checking-loading, it is easy to cause damage to the test equipment, and it also wastes huge manpower and material resources. The relative positions of the power supply, standard instruments and measuring instruments are not the same, which increases the uncertainty of the distribution parameters, thus causing the additional error introduced by the measurement system to be very unstable, sometimes seriously affecting the measurement results and even affecting the test results. Judgment of product performance. Moreover, the higher the CVT voltage level and the larger the volume and weight of the test equipment, the more difficult it is for this unmountable calibration method to meet the requirements for measurement accuracy and work efficiency in the field calibration of 500kV~1000kV CVT.

Contents of the invention

The purpose of the present invention is to improve the existing verification methods and verification systems for super/ultra-high voltage on-site CVT verification in terms of structure, transportation and measurement, and to provide super/ultra-high voltage CVT The integrated standard device for on-site verification can verify/calibrate the error of 750kV/1000kV CVT on site without loading and unloading.

The technical solution of the present invention is: an integrated standard device for super/ultra-high voltage CVT on-site verification, the device includes a test power supply, a test lifting platform, a standard appliance, a measuring instrument and a vehicle-mounted platform, and is characterized in that: the test power supply It is composed of cascaded upper and lower test transformers, secondary compensation reactors and voltage regulators; the standard appliance is composed of series upper and lower standard voltage transformers and high-voltage isolation transformers; the test lifting platform consists of a base, a transmission mechanism and insulation The supporting parts; the measuring instruments include the transformer calibrator and the load box, and all the equipment are fixedly installed on the vehicle-mounted platform, and the test lifting platform can be raised and lowered in the vertical direction;

The lower-level standard voltage transformer and the high-voltage isolation transformer form the first SF6 closed combined electrical unit GIS1, and the upper-level standard voltage transformer and the upper-level test transformer form the second SF6 closed combined electrical unit GIS2, which is placed on the test lifting platform ; The GIS1 unit and the lower-level test transformer are respectively placed on both sides of the test lifting platform, and the GIS1 unit, the GIS2 unit, the lower-level test transformer, and the secondary compensation reactor are connected in sequence, followed by the voltage regulation measurement area, the voltage regulator and the measurement The instrument is placed in the pressure regulation measurement area.

The above-mentioned integrated standard device for super/ultra-high voltage CVT field verification is characterized in that: the low-voltage winding of the upper-level test transformer is connected in parallel with the excitation winding of the lower-level test transformer, and the low-voltage winding of the upper-level standard voltage transformer is connected with the high-voltage isolation transformer. The high voltage windings are connected in parallel.

The above-mentioned integrated standard device for super/ultra-high voltage CVT on-site verification is characterized in that: the low-voltage side of the test transformer is provided with a reactive power compensation winding, and the reactive power compensation winding supplies power to the secondary compensation reactor.

The above-mentioned integrated standard device for super/ultra-high voltage CVT field verification is characterized in that: the GIS1 unit and the GIS2 unit both include the same components: a pressure equalizing ring, a high voltage bushing and a tee connector.

The above-mentioned integrated standard device for super/ultra-high voltage CVT field verification is characterized in that: the high-voltage winding of the lower-level standard voltage transformer is wound outside the low-voltage winding, and is co-wound on the transformer core, and the horizontal semi-horizontal fixed.

The above-mentioned integrated standard device for super/ultra-high voltage CVT on-site verification is characterized in that the high voltage winding of the upper test transformer is wound outside the low voltage winding and co-wound on the transformer core.

The above-mentioned integrated standard device for super/ultra-high voltage CVT on-site verification is characterized in that: the high voltage of the standard voltage transformer, the high voltage isolation transformer and the test transformer are all drawn out through the high voltage conductor and the high voltage bushing.

The above-mentioned integrated standard device for super/ultra-high pressure CVT on-site verification is characterized in that: the GIS1 unit and the GIS2 unit adopt an airtight design, and the inside is filled with SF6 gas at a pressure of 0.35-0.4 MPa.

The beneficial effects of the present invention are: 1. The test transformer and the standard voltage transformer of the integrated series standard device are respectively designed as a cascade type and a series structure, and _SF6 gas insulation is adopted, which greatly reduces the difficulty of insulation design of a single device, And reduce its volume and weight, which provides convenience for vehicle transportation; 2. Design the upper-level standard voltage transformer and the upper-level test transformer into an integrated GIS unit, effectively reducing the number of bushings and reducing manufacturing costs; 3. Adjustable through adjustment The inductance of the reactor compensates the reactive power of the test transformer, reducing the output capacity of the voltage regulator and power supply; 4. After adopting the integrated design, the calibration work can be carried out without on-site loading and unloading, which greatly improves the work efficiency; 5. Measurement , the position of the test power supply, standard instruments and measuring instruments on the vehicle platform is relatively fixed, which reduces the additional error introduced by the calibration system itself during the measurement and reduces the measurement uncertainty.

Description of drawings

Fig. 1 is a schematic layout diagram of an integrated standard device for on-site verification of an EHV/UHV CVT in an embodiment of the present invention.

Fig. 2 is a schematic diagram of the equipment layout in the measurement area in Fig. 1 .

FIG. 3 is a schematic diagram of the structure of GIS1 in FIG. 1 .

FIG. 4 is a schematic diagram of the structure of GIS2 in FIG. 1 .

Fig. 5 is a schematic circuit diagram of an integrated standard device for super/ultra-high voltage CVT field verification in Fig. 1 .

Fig. 6 is a circuit diagram of an EH/UHV CVT on-site error checking circuit according to an embodiment of the present invention.

Detailed ways

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

Marking description in Figure 1: 1-lower standard voltage transformer, 2-high voltage isolation transformer, 3-transmission mechanism, 4-insulation support, 5-superior standard voltage transformer, 6-superior test transformer, 7-lower Test transformer, 8-secondary compensation reactor, 9-base, 10-vehicle platform.

Explanation of marks in Fig. 2: 11 - voltage regulator T _m , 12 - transformer calibrator HE, 13 - load box Y1, 14 - load box Y2.

Marking description in Figure 3: 15-voltage equalizing ring, 16-high voltage bushing, 17-tee connection body, 18-standard transformer high-voltage winding, 19-standard transformer low-voltage winding, 20-high voltage conductor, 21-mutual inductance Iron core, 22-HVIT high-voltage winding, 23-HVIT low-voltage winding, 24-HVIT iron core, d-insulation distance between coaxial electrodes.

Notes in Figure 4: 25 - low-voltage winding of the test transformer, 26 - high-voltage winding of the test transformer, 27 - iron core of the transformer.

Explanation of the marks in Figure 5: 28 - compensation winding, 29 - test transformer excitation winding;

Notes in Fig. 6: CVT-capacitive voltage transformer under test, C1, C2-dividing capacitance of CVT under test, L _k -compensation reactor in CVT.

The equipment layout diagram of the integrated standard device for super/ultra-high voltage CVT on-site verification of the embodiment of the present invention is shown in Figure 1. The device includes a test power supply, a test lifting platform, standard appliances and measuring instruments. Among them, the test power supply is composed of the upper-level test transformer 6, the lower-level test transformer 7, the secondary compensation reactor 8 and the voltage regulator 11; the standard equipment is composed of the upper-level standard voltage transformer 5, the lower-level standard voltage transformer 1 and the high-voltage isolation transformer 2 Composition; the test lifting platform is composed of a base 12, a transmission mechanism 6 and an insulating support 7; the measuring instrument includes a transformer calibrator 15, a load box 16 and a load box 17. Before the test, use the lifting transmission mechanism to raise the test lifting platform to the upper end surface of the insulating support 7, and the insulation level with the ground potential is half of the test voltage, and then lower the platform to its original position after the test. During the test, the inductance of the secondary compensation reactor 8 can be adjusted within a certain range, and is used for reactive power compensation of the test line, and reduces the output capacity of the voltage regulator 11 and the power supply.

As shown in Figure 2, a voltage regulator 11, a transformer calibrator 12 and two load boxes 13, 14 are sequentially placed in the voltage regulation measurement area.

As shown in Figure 3 and Figure 4, GIS1 is mainly composed of a lower-level standard voltage transformer 1 and a high-voltage isolation transformer (HVIT) 2. The high-voltage winding 18 of the lower-level standard voltage transformer is wound outside the low-voltage winding 19 and co-wound on the mutual On the iron core 21 of the device, it is fixed horizontally and semi-horizontally; the high-voltage winding 22 and low-voltage winding 23 of the HVIT are reliably shielded with coaxial electrodes, and the insulation distance between the coaxial electrodes is d. GIS2 is mainly composed of upper-level standard voltage transformer 5 and upper-level test transformer 6 . In addition, GIS1 and GIS2 also include components such as voltage equalizing ring 15 , high-voltage bushing 16 and tee connector 17 . The structure of the upper-level standard voltage transformer is the same as that of the lower-level standard voltage transformer 1; the high-voltage winding 26 of the upper-level test transformer 6 is wound outside the low-voltage winding 25 and co-wound on the transformer core 27 . The high voltages of the standard voltage transformer, HVIT and test transformer are all drawn out through the high voltage conductor 20 and the high voltage bushing 16 . GIS1 and GIS2 adopt airtight design, and the inside is filled with SF ₆ gas with a pressure of 0.35-0.4MPa.

In the schematic circuit diagram of the integrated standard device for super/ultra-high voltage CVT field verification shown in Fig. 5, the voltage regulator 11 has an output voltage of 380V/420V and a capacity of 150kVA. The capacity of the lower test transformer 7 is 1000kVA, the rated voltage of the compensation winding 28 is 10kV, and the output rated voltage of the high voltage winding 26 is 320kV. The upper test transformer 6 has a capacity of 500kVA, and the high voltage winding 26 outputs a rated voltage of 320kV. The inductance of the secondary compensation reactor 8 is adjustable within the range of 0.3H~0.6H.

，高压对地电容与回路电容之和约为5000pF~8000pF。试验时，先在20%额定电压下调节二次补偿电抗器8的电感量，使调压器11的输入电流达到最小，此时试验线路工作在谐振状态，然后将电压依次升至各校验点，按图6所示测量线路，并根据《JJG1021-2007电力互感器检定规程》中的相关规定，即可对CVT的误差进行现场校验。 In the embodiment of the super/ultra-high voltage CVT field error calibration circuit shown in Fig. 6, the rated voltage U _N of the CVT =

, The sum of the high-voltage ground capacitance and the loop capacitance is about 5000pF~8000pF. During the test, first adjust the inductance of the secondary compensation reactor 8 at 20% of the rated voltage to minimize the input current of the voltage regulator 11. At this time, the test line works in a resonant state, and then raise the voltage to each calibration level in turn. Point, according to the measurement line shown in Figure 6, and according to the relevant regulations in the "JJG1021-2007 Power Transformer Verification Regulations", the error of the CVT can be verified on site.

Claims (7)

1. integrated standard set-up of ultra-high/extra-high voltage CVT field-checking, this device comprises experiment power supply, test hoistable platform, standard utensil, surveying instrument and vehicular platform, it is characterized in that: described experiment power supply is made up of the upper and lower level of tandem formula testing transformer, second compensation reactor and pressure regulator; The standard utensil is made up of the upper and lower grade standard voltage transformer (VT) of tandem and high pressure isolation transformer; The test hoistable platform is made up of base, gear train and insulated support; Surveying instrument comprises mutual-inductor tester and Burden box, and all devices all is fixedly mounted on the vehicular platform, and wherein testing hoistable platform in vertical direction can lifting;

Subordinate's standard potential transformer and high pressure isolation transformer are formed first SF6 gas insulated metal enclosed swit chgear unit GIS1, higher level's standard potential transformer and higher level's testing transformer are formed second SF6 gas insulated metal enclosed swit chgear unit GIS2, and place on the test hoistable platform; Described GIS1 unit and subordinate's testing transformer place the both sides of test hoistable platform respectively, GIS1 unit, GIS2 unit, subordinate's testing transformer, second compensation reactor connect successively, thereafter be the pressure regulation measurement zone, pressure regulator and surveying instrument place the pressure regulation measurement zone.

2. the integrated standard set-up of ultra-high/extra-high voltage CVT field-checking according to claim 1, it is characterized in that: the low pressure winding of higher level's testing transformer is in parallel with the field copper of subordinate's testing transformer, and the low pressure winding of higher level's standard potential transformer is in parallel with the high pressure winding of high pressure isolation transformer.

3. the integrated standard set-up of ultra-high/extra-high voltage CVT field-checking according to claim 1, it is characterized in that: the low-pressure side of subordinate's testing transformer arranges the reactive-load compensation winding, and this reactive-load compensation winding is the power supply of second compensation reactor.

4. the integrated standard set-up of ultra-high/extra-high voltage CVT field-checking according to claim 1, it is characterized in that: described GIS1 unit and GIS2 unit include identical assembly: grading ring, bushing and threeway connector.

5. the integrated standard set-up of ultra-high/extra-high voltage CVT field-checking according to claim 1 is characterized in that: the high pressure winding of subordinate's standard potential transformer is around the low pressure winding outside, and altogether on transformer iron core, horizontal reclining posture is fixed.

6. the integrated standard set-up of ultra-high/extra-high voltage CVT field-checking according to claim 1 is characterized in that: the high pressure winding of higher level's testing transformer is around the low pressure winding outside, and altogether on transformer core.

7. the integrated standard set-up of ultra-high/extra-high voltage CVT field-checking according to claim 1 is characterized in that: GIS1 unit and GIS2 unit adopt gas-tight design, and the SF with 0.35～0.4MPa pressure is filled in inside ₆Gas.

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