Energy extraction shunt reactor loss measurement circuit and method thereof

Abstract

The invention provides an energy extraction paralleling reactor loss measurement circuit and method, which not only can effectively realize the load loss test of an energy extraction paralleling reactor, but also can accurately measure the loss of the reactor. The energy extraction shunt reactor loss measurement circuit comprises a voltage regulator, a primary intermediate transformer, a compensation capacitor bank, a secondary intermediate transformer, a high-voltage standard capacitor, a current comparator, a shunt reactor main coil, an energy extraction coil and a load shunt reactor which are connected in sequence, and the load shunt reactor comprises A, B and C three-phase windings. The A-phase winding and the B-phase winding are connected in parallel and then are connected in series with the C-phase winding, the output end of the energy extraction coil is connected with the C-phase winding, and the voltage transformer and the current transformer are both connected between the energy extraction coil and the load shunt reactor. A loss bridge is connected between the high-voltage standard capacitor and the current comparator, and a loss bridge is connected between the current transformer and the voltage transformer.

Description

Technical Field

[0001] The invention relates to the technical field of reactor testing, and in particular to a loss measurement circuit and method for an energy extraction shunt reactor. Background Art

[0002] Although my country has a vast territory, the matching degree between energy centers and load centers is relatively low. To solve this problem, the country has been committed to the construction and implementation of the "aorta" of energy transportation of "west-to-east power transmission, north-to-south power transmission, water-fire mutual assistance, wind-light complementarity", especially the large-scale construction and commercial operation of ultra-high voltage AC and DC transmission projects in recent years, which will be of great practical significance for the early realization of the grand goal of "carbon peak and carbon neutrality".

[0003] For ultra-high voltage and extra-high voltage AC and DC long-distance power transmission, as the line length increases, its stray capacitance to the ground also increases. Under light load conditions, a "capacitance rise" phenomenon will occur at the load end, thereby affecting the power supply quality and equipment operation reliability. To solve this problem, a switch station is usually required between the power source and the load end, that is, the capacitive current is balanced through the reactor to alleviate the voltage increase problem caused by long-distance power transmission.

[0004] Switch stations are sometimes located in remote areas or in the mountains. In this case, if we consider adding extra-high or ultra-high voltage station transformers or providing a separate distribution line, it is not only uneconomical but also increases some uncontrollable factors in the later operation and maintenance process. At the same time, the auxiliary equipment of the switch station requires power, so the single-phase shunt reactor with energy extraction coil came into being. This type of reactor not only realizes the inductive reactive power compensation of the power grid, but also provides the necessary station power for the switch station, playing the dual role of reactive power compensation and active power supply.

[0005] In order to measure the loss of equipment in the power grid, or to measure the transmission efficiency of the transmission line, etc., loss tests must be carried out on power equipment. The existing single-phase shunt reactor with an energy extraction coil, the reactor coil is usually mounted on a main column formed by the staggered stacking of air gaps and iron core cakes, the energy extraction coil is mounted on a side yoke, and the side yoke forms a closed ferromagnetic circuit with the upper and lower iron yokes, but there is an air gap between the main column of the reactor core and the upper and lower iron yokes, and the two windings are not on the same iron core column, there will be deviations in magnetic field coupling and other aspects, so the coupling degree between the energy extraction coil and the main coil of the reactor shunt reactor is not as high as that of a conventional transformer, and the capacity of the energy extraction coil is usually small, so it is impossible to obtain accurate loss results by referring to the test method of conventional transformers. Summary of the invention

[0006] In view of the above problems, the present invention provides a power extraction shunt reactor loss measurement circuit and method, which can not only effectively implement the power extraction shunt reactor load loss test, but also accurately measure the reactor loss.

[0007] The present invention adopts the following technical scheme, a power extraction shunt reactor loss measurement circuit, including a voltage regulator, a primary intermediate transformer, a compensation capacitor group, a secondary intermediate transformer, a high-voltage standard capacitor, a current comparator, a shunt reactor main coil, a power extraction coil, and a load shunt reactor connected in sequence, the load shunt reactor includes three-phase windings A, B, and C, the A-phase winding and the B-phase winding are connected in parallel and then connected in series with the C-phase winding, the output end of the power extraction coil is connected to the C-phase winding, a voltage transformer and a current transformer are both connected between the power extraction coil and the load shunt reactor, and a loss bridge is connected between the high-voltage standard capacitor and the current comparator, and between the current transformer and the voltage transformer.

[0008] Furthermore, the loss bridge is divided into a first loss bridge and a second loss bridge, and the first loss bridge and the second loss bridge both adopt the Havley model 2877 loss bridge;

[0009] Further, one end of the high-voltage standard capacitor is connected between one end of the high-voltage side of the secondary intermediate transformer and one end of the main coil of the shunt reactor, the current comparator is connected between the other end of the high-voltage side of the secondary intermediate transformer and the other end of the main coil of the shunt reactor, the other end of the high-voltage standard capacitor is connected to the first loss bridge, and the current comparator is connected to the first loss bridge;

[0010] Further, one terminal of the A-phase winding and the B-phase winding connected in parallel is connected to one end of the C-phase winding, the other end of the C-phase winding is connected to one end of the output side of the energy extraction coil, the other terminal of the A-phase winding and the B-phase winding connected in parallel is connected to one end of the voltage transformer and the current transformer, the other end of the voltage transformer is connected to one end of the output side of the energy extraction coil, the other end of the current transformer is connected to the other end of the output side of the energy extraction coil, and the second loss bridge is connected between the voltage transformer and the current transformer;

[0011] Furthermore, the primary intermediate transformer adopts a 220kV intermediate transformer; the secondary intermediate transformer adopts a 2000kV single-phase intermediate transformer; the current comparator adopts a 0.001-level current comparator; the current transformer adopts a 0.05-level current transformer;

[0012] A method for measuring the loss of an energy extraction shunt reactor comprises the following steps:

[0013] S1. Obtain the rated load according to the rated output voltage and output current of the energy extraction coil;

[0014] S2. Obtain the equivalent impedance of the load shunt reactor according to the connection mode of the three-phase windings A, B, and C in the load shunt reactor;

[0015] S3. If the equivalent impedance of the load shunt reactor does not meet the rated load, adjust the C-phase winding coil so that the equivalent impedance of the load shunt reactor just reaches the rated load;

[0016] S4. Apply voltage to the energy-extracting shunt reactor. When the voltage measured by the high-voltage standard capacitor is equal to the rated voltage of the main coil line end of the shunt reactor, the first loss bridge and the second loss bridge record readings, and make an algebraic difference between the values ​​recorded by the first loss bridge and the second loss bridge, and convert the difference into a loss value corresponding to the reference temperature, which is the total loss of the energy-extracting shunt reactor.

[0017] Further, in step S3, if the equivalent impedance of the load shunt reactor is less than the rated load, a corresponding cable is wound around the outer side of the C-phase winding; if the equivalent impedance of the load shunt reactor is greater than the rated load, the C-phase winding is used as the equivalent impedance of the load shunt reactor;

[0018] Furthermore, the calculation formula for the rated load is:

[0019] Wherein, Z is the rated load of the energy extraction coil;

[0020] U N is the rated output voltage of the energy extraction coil;

[0021] I is the output current of the energy extraction coil;

[0022] Furthermore, in step S2, the equivalent impedance calculation formula of the load shunt reactor is:

[0023]

[0024] Where R is the equivalent impedance of the load shunt reactor;

[0025] R A is the resistance of phase A winding;

[0026] R B is the resistance of the B-phase winding;

[0027] R C is the resistance of the C-phase winding;

[0028] Furthermore, the total loss of the energy extraction shunt reactor is calculated as follows:

[0029]

[0030] Among them, K t is the temperature conversion factor;

[0031] t is the average temperature of the coil wire during measurement;

[0032] I1 is the current flowing through the main coil of the shunt reactor, r1 is the winding resistance of the main coil of the shunt reactor;

[0033] I2 is the current flowing through the energy extraction coil, and r2 is the resistance of the energy extraction coil winding;

[0034] P Kt is the difference between the values ​​recorded by the first loss bridge and the second loss bridge at temperature t.

[0035] The beneficial effect of the present invention is that the output power of the voltage regulator is gradually boosted through two intermediate transformers to finally meet the requirements of the test voltage of the reactor line end, and by adjusting the connection method of the three-phase winding in the load shunt reactor, the equivalent impedance can be flexibly adjusted, so that the total loss of the reactor under the rated full load state can be directly measured, and the accuracy of the loss measurement of the energy extraction shunt reactor can be ensured, which has good economic use value. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a circuit schematic diagram of the present invention. DETAILED DESCRIPTION

[0037] like Figure 1 As shown, a loss measurement circuit of an energy extraction shunt reactor of the present invention comprises a voltage regulator 1 (an industrial frequency generator set may also be used), a primary intermediate transformer 2, a compensation capacitor group 3, a secondary intermediate transformer 4, a high-voltage standard capacitor 5, a current comparator 6, a shunt reactor main coil 8, an energy extraction coil 9 and a load shunt reactor 12 acting as a load, which are connected in sequence. The load shunt reactor 12 comprises three-phase windings A, B and C. The A-phase winding and the B-phase winding are connected in parallel and then connected in series with the C-phase winding. The output end of the energy extraction coil 9 is connected to the C-phase winding. A voltage transformer 11 and a current transformer 10 are both connected between the energy extraction coil 9 and the load shunt reactor 12. Loss bridges are connected between the high-voltage standard capacitor 5 and the current comparator 6, and between the current transformer 10 and the voltage transformer 11.

[0038] The loss bridge is divided into a first loss bridge 7 and a second loss bridge 13, and both the first loss bridge 7 and the second loss bridge 13 adopt the Havley model 2877 loss bridge; one end of the high-voltage standard capacitor 5 is connected between one end of the high-voltage side of the secondary intermediate transformer 4 and one end of the main coil 8 of the shunt reactor, the current comparator 6 is connected between the other end of the high-voltage side of the secondary intermediate transformer 4 and the other end of the main coil 8 of the shunt reactor, the other end of the high-voltage standard capacitor 5 is connected to the first loss bridge 7, and the current comparator 6 is connected to a loss bridge.

[0039] One terminal of the A-phase winding and the B-phase winding connected in parallel is connected to one end of the C-phase winding, and the other end of the C-phase winding is connected to one end of the output side of the energy extraction coil 9. The other terminal of the A-phase winding and the B-phase winding connected in parallel is connected to one end of the voltage transformer 11 and the current transformer 10. The other end of the voltage transformer 11 is connected to one end of the output side of the energy extraction coil 9, and the other end of the current transformer 10 is connected to the other end of the output side of the energy extraction coil 9. The second loss bridge 13 is connected between the voltage transformer 11 and the current transformer 10.

[0040] The primary intermediate transformer 2 adopts a 220kV intermediate transformer; the secondary intermediate transformer 4 adopts a 2000kV single-phase intermediate transformer; the current comparator 6 adopts a 0.001-level current comparator; and the current transformer 10 adopts a 0.05-level current transformer.

[0041] A method for measuring the loss of an energy extraction shunt reactor comprises the following steps:

[0042] S1, obtaining a rated load according to the rated output voltage and output current of the energy extraction coil 9;

[0043] Specifically, the calculation formula for the rated load is:

[0044] Wherein, Z is the rated load of the energy extraction coil 9;

[0045] U N is the rated output voltage of the energy extraction coil 9;

[0046] I is the output current of the energy extraction coil 9;

[0047] S2. Obtain the equivalent impedance of the load shunt reactor 12 according to the connection mode of the three-phase windings A, B, and C in the load shunt reactor 12;

[0048] Specifically, the equivalent impedance calculation formula of the load shunt reactor 12 is:

[0049]

[0050] Wherein, R is the equivalent impedance of the load shunt reactor 12;

[0051] R A is the resistance of phase A winding;

[0052] R B is the resistance of the B-phase winding;

[0053] R C is the resistance of the C-phase winding;

[0054] S3. If the equivalent impedance of the load shunt reactor 12 does not meet the rated load, the C-phase winding coil is adjusted so that the equivalent impedance of the load shunt reactor 12 just reaches the rated load;

[0055] Specifically, if the equivalent impedance of the load shunt reactor 12 is less than the rated load, the corresponding cable is wound around the outside of the C-phase winding;

[0056] The embodiments of the present invention are illustrated by using specific numerical values:

[0057]

[0058] Since 51.3Ω is 3Ω smaller than the required value 54.3Ω, a 70 square cable is selected based on existing experience and existing resources, that is, 14 turns of 70 square cables are wound around the outside of the C-phase winding, that is, the temporarily wound cable is connected in series with the C-phase winding coil. After this transformation, the equivalent impedance of the load shunt reactor 12 just meets the requirements of the rated load size;

[0059] If the equivalent impedance of the load shunt reactor is greater than the rated load, the C-phase winding is used as the equivalent impedance of the load shunt reactor. At this time, the A-phase winding and the B-phase winding are not connected;

[0060] S4, based on the modified winding circuit in step S3, apply voltage to the energy extraction shunt reactor, when the voltage measured by the high-voltage standard capacitor 5 is equal to the rated voltage of the line end of the main coil 8 of the shunt reactor, start recording the readings of the first loss bridge 7 connected to the 0.001-level current comparator 6 and the second loss bridge 13 connected to the 0.05-level current transformer 10, and finally make an algebraic difference between the values ​​recorded by the first loss bridge 7 and the second loss bridge 13, and convert the difference into a loss value corresponding to the reference temperature of 75°C, which is the total loss of the energy extraction shunt reactor;

[0061] For transformer equipment, the standards and specifications stipulate that their losses are converted to the reference temperature (75℃ is calculated based on the annual average temperature of 20℃ in the Central Plains of my country, plus the average temperature rise of 55K of the coil to oil in the equipment) for easy comparison;

[0062] The total loss calculation formula of the energy extraction shunt reactor is:

[0063]

[0064] Among them, K t is the temperature conversion factor; for copper conductor

[0065] t is the average temperature of the coil wire during measurement;

[0066] I1 is the current flowing through the main coil 8 of the shunt reactor, r1 is the winding resistance of the main coil 8 of the shunt reactor;

[0067] I2 is the current flowing through the energy extraction coil 9, r2 is the winding resistance of the energy extraction coil 9;

[0068] P Kt is the difference between the values ​​recorded by the first loss bridge and the second loss bridge at temperature t.

[0069] The measuring principle of the present invention is:

[0070] The voltage required for the test line end of the energy extraction shunt reactor is output through the voltage regulator 1, and is output to the energy extraction shunt reactor after two-stage boosting through the 220kV intermediate transformer and the 2000kV single-phase intermediate transformer, meeting the requirements of the reactor line end test voltage; then the rated load Z is calculated according to the rated voltage and current of the energy extraction coil 9, and a suitable load is selected, such as a transformer, a capacitor, a reactor, a pure resistor, etc. The embodiment of the present invention uses a dry load shunt reactor product, and through the modification of the wiring method of the dry load shunt reactor 12, a temporary wire turn is wound around the outside of the C-phase coil and connected in series to the C-phase coil line end, so as to achieve the requirement that its equivalent impedance is equal to the load value of the energy extraction coil, and finally accurately achieves the requirements of the energy extraction winding on the load value, and finally enables the energy extraction shunt reactor loss measurement to be carried out smoothly under all rated operating conditions, and its test data is accurate, which will have very important engineering value for the inspection of product quality and the further optimization and improvement of subsequent products.

[0071] In summary, the beneficial effects of the present invention are:

[0072] 1. Through the above measurement method, the total loss of the energy extraction shunt reactor under rated full load operation conditions can be directly measured;

[0073] 2. It can ensure that the main coil and energy extraction coil of the shunt reactor can reach their rated working current and rated voltage at the same time;

[0074] 3. Select load shunt reactor as the test load of the energy extraction coil, and its equivalent impedance value can be adjusted flexibly and easily guaranteed;

[0075] The above measures can ensure the accuracy of loss measurement of energy-extracting shunt reactors, help analyze the quality status of the reactor and carry out further optimization, etc., and have the characteristics of small investment, simple wiring, convenient operation, strong practicality, etc.; and the present invention is suitable for loss measurement of all shunt reactors with energy extraction coils of 220kV and above.

[0076] In the figure, A1, B1, and C1 serve as the high-voltage side output terminals of the primary intermediate transformer 2, and a1, b1, and c1 serve as the low-voltage side input terminals of the primary intermediate transformer 2;

[0077] A2 and X2 serve as high-voltage side output terminals of the secondary intermediate transformer 4 , and a2 and x2 serve as low-voltage side input terminals of the secondary intermediate transformer 4 .

[0078] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0079] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A loss measurement circuit for an energy extraction shunt reactor, characterized in that: It includes a voltage regulator, a primary intermediate transformer, a compensation capacitor group, a secondary intermediate transformer, a high-voltage standard capacitor, a current comparator, a shunt reactor main coil, an energy extraction coil, and a load shunt reactor, which are connected in sequence. The load shunt reactor includes three-phase windings A, B, and C. The A-phase winding and the B-phase winding are connected in parallel and then connected in series with the C-phase winding. The output end of the energy extraction coil is connected to the C-phase winding. A voltage transformer and a current transformer are both connected between the energy extraction coil and the load shunt reactor. A lossy bridge is connected between the high-voltage standard capacitor and the current comparator, and between the current transformer and the voltage transformer.

2. The energy extraction shunt reactor loss measurement circuit according to claim 1, characterized in that: The loss bridge is divided into a first loss bridge and a second loss bridge, and the first loss bridge and the second loss bridge both adopt the Havley model 2877 loss bridge.

3. The energy extraction shunt reactor loss measurement circuit according to claim 2, characterized in that: One end of the high-voltage standard capacitor is connected between one end of the high-voltage side of the secondary intermediate transformer and one end of the main coil of the shunt reactor, the current comparator is connected between the other end of the high-voltage side of the secondary intermediate transformer and the other end of the main coil of the shunt reactor, the other end of the high-voltage standard capacitor is connected to the first loss bridge, and the current comparator is connected to the loss bridge.

4. The energy extraction shunt reactor loss measurement circuit according to claim 2, characterized in that: One terminal of the A-phase winding and the B-phase winding connected in parallel is connected to one end of the C-phase winding, and the other end of the C-phase winding is connected to one end of the output side of the energy extraction coil. The other terminal of the A-phase winding and the B-phase winding connected in parallel is connected to one end of the voltage transformer and the current transformer, the other end of the voltage transformer is connected to one end of the output side of the energy extraction coil, and the other end of the current transformer is connected to the other end of the output side of the energy extraction coil. The second loss bridge is connected between the voltage transformer and the current transformer.

5. The energy extraction shunt reactor loss measurement circuit according to claim 1, characterized in that: The first-level intermediate transformer adopts a 220kV intermediate transformer; the second-level intermediate transformer adopts a 2000kV single-phase intermediate transformer; the current comparator adopts a 0.001-level current comparator; and the current transformer adopts a 0.05-level current transformer.

6. A method for measuring the loss of an energy extraction shunt reactor, characterized in that: A power extraction shunt reactor loss measurement circuit as claimed in any one of claims 1 to 5 is used; the method comprises the following steps: S1. Obtain the rated load according to the rated output voltage and output current of the energy extraction coil; S2. Obtain the equivalent impedance of the load shunt reactor according to the connection mode of the three-phase windings A, B, and C in the load shunt reactor; S3. If the equivalent impedance of the load shunt reactor does not meet the rated load, adjust the C-phase winding coil so that the equivalent impedance of the load shunt reactor just reaches the rated load; S4. Apply voltage to the energy-extracting shunt reactor. When the voltage measured by the high-voltage standard capacitor is equal to the rated voltage of the main coil line end of the shunt reactor, the first loss bridge and the second loss bridge record readings, and make an algebraic difference between the values ​​recorded by the first loss bridge and the second loss bridge, and convert the difference into a loss value corresponding to the reference temperature, which is the total loss of the energy-extracting shunt reactor.

7. A method for measuring loss of an energy extraction shunt reactor according to claim 6, characterized in that: In step S3, if the equivalent impedance of the load shunt reactor is less than the rated load, the corresponding cable is wound on the outside of the C-phase winding; if the equivalent impedance of the load shunt reactor is greater than the rated load, the C-phase winding is used as the equivalent impedance of the load shunt reactor.

8. A method for measuring loss of an energy extraction shunt reactor according to claim 6, characterized in that: The formula for calculating the rated load is: Wherein, Z is the rated load of the energy extraction coil; U N is the rated output voltage of the energy extraction coil; I is the output current of the energy extraction coil.

9. A method for measuring loss of an energy extraction shunt reactor according to claim 6, characterized in that: In step S2, the equivalent impedance calculation formula of the load shunt reactor is: Where R is the equivalent impedance of the load shunt reactor; R A is the resistance of phase A winding; R B is the resistance of the B-phase winding; R C is the resistance of the C-phase winding.

10. A method for measuring loss of an energy extraction shunt reactor according to claim 6, characterized in that: The calculation formula of the total loss of the energy extraction shunt reactor is: Among them, K t is the temperature conversion factor; t is the average temperature of the coil wire during measurement; I1 is the current flowing through the main coil of the shunt reactor, r1 is the winding resistance of the main coil of the shunt reactor; I2 is the current flowing through the energy extraction coil, and r2 is the resistance of the energy extraction coil winding; P Kt is the difference between the values ​​recorded by the first loss bridge and the second loss bridge at temperature t.

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