Construction method and system for preventing cable heating and eddy current loss of dynamic compensation system

Abstract

The invention relates to the field of electrical protection devices, in particular to a construction method and system for preventing heating and eddy current loss of a dynamic compensation system cable, a high-voltage cabinet is used for providing an A, B and C three-phase alternating current power supply for an SVC dynamic reactive power compensation device, and the SVC dynamic reactive power compensation device is connected with the high-voltage cabinet through an A, B and C three-phase power cable. The power cable is laid through a cable bridge, and the method comprises the steps that the cable bridge is an aluminum alloy trapezoid bridge, a grounding wire is installed at the connecting position of the cable bridge, a high-voltage cabinet is grounded through a single-core cable, and the three-phase power cable is laid in a layered mode. The cable bridge has the advantages that the cable bridge is an aluminum alloy trapezoid bridge, when the SSVC dynamic reactive power compensation device is completely put into operation, eddy current heating is reduced, and due to the trapezoid bridge, the heat dissipation effect of the cable and the cable bridge is improved; the high-voltage cabinet adopts a mode that the single-core cable is grounded and the SVC dynamic reactive power compensation device does not need to be grounded, so that the induced voltage difference generated by a shielding layer of the single-core cable is reduced.

Description

Technical Field

[0001] The present invention relates to the field of electrical protection devices, and particularly to a construction method and system for preventing cable heating and eddy current loss in a dynamic compensation system. Background Art

[0002] In a certain hot rolling mill, the 10KV power supply SVC dynamic reactive power compensation device consists of TCR, secondary filter, tertiary filter, fifth filter, seventh filter, and eleventh filter. After the equipment is put into operation, the TCR current can reach up to 3000A. Since the cable tray is a semi-closed iron tray and the three-phase power cables are laid in the same layer of the cable tray, eddy currents are likely to be generated, and the "pin" arrangement of the cables affects the heat dissipation effect. It is measured that the highest temperature of the cable tray reaches 130 degrees, and the cable temperature is 110 degrees.

[0003] To ensure the stable operation of the SVC dynamic reactive power compensation device and prevent the three-phase power cables from heating up, the seventh filter and the eleventh filter are removed to reduce the TCR current. Since the SVC dynamic reactive power compensation device is not fully put into operation, the power factor of the 10KV power supply system is reduced; during steel rolling, the power factor COS￠≤0.5 (when the SVC dynamic reactive power compensation device is fully put into operation during steel rolling, the power factor is above 0.98, and the daily average power factor is about 0.9), which greatly reduces the utilization rate of electric energy.

[0004] The SVC dynamic reactive power compensation device is also used to stabilize the voltage of the 10KV system. When the SVC dynamic reactive power compensation device is fully put into operation, the voltage fluctuation during steel rolling and non-steel rolling is within 400V. If the seventh filter and the eleventh filter are removed, the voltage fluctuation during steel rolling and non-steel rolling is about 700V. The system voltage fluctuates greatly, which is likely to cause damage to the components of electrical equipment and affect production. Summary of the Invention

[0005] The purpose of the present invention is to provide a construction method and system for preventing cable heating and eddy current loss in a dynamic compensation system, which can reduce the temperature of the three-phase power cables, improve the power factor, reduce the voltage fluctuation amplitude of the high-voltage system, and ensure the stable operation of the equipment without removing the seventh filter and the eleventh filter in the SVC dynamic reactive power compensation device.

[0006] To achieve the above purpose, the present invention is realized through the following technical solutions:

[0007] A construction method for preventing cable heating and eddy current loss in a dynamic compensation system specifically includes:

[0008] S1. The cable tray adopts an aluminum alloy trapezoidal tray;

[0009] S2. Install a grounding wire at the connection of the cable tray;

[0010] S3. Ground the high-voltage switchgear using a single-core cable, and the SVC dynamic reactive power compensation device does not need to be grounded;

[0011] S4. Lay the three-phase power cables in layers.

[0012] In S4, the cable tray is set in layers, and the A, B, and C phase power cables are respectively laid in the cable trays of different layers.

[0013] A system for preventing the cables of the dynamic compensation system from heating and eddy current loss, including an SVC dynamic reactive power compensation device and a high-voltage switchgear. The high-voltage switchgear is used to provide three-phase AC power of A, B, and C to the SVC dynamic reactive power compensation device. The SVC dynamic reactive power compensation device and the high-voltage switchgear are connected by three-phase power cables of A, B, and C, and the power cables are laid through the cable tray.

[0014] Compared with the prior art, the beneficial effects of the present invention are:

[0015] 1. The cable tray adopts an aluminum alloy trapezoidal tray to avoid eddy current loss. When the SSVC dynamic reactive power compensation device is fully put into operation, the eddy current heating is reduced. At the same time, due to the trapezoidal tray, the heat dissipation effect of the cables and the cable tray is improved under the ventilation state;

[0016] 2. The high-voltage switchgear is grounded using a single-core cable while the SVC dynamic reactive power compensation device does not need to be grounded, which reduces the induced voltage difference generated by the shielding layer of the single-core cable and avoids the generation of circulating current in the cable shielding layer, thereby reducing the heating loss;

[0017] 3. Install a grounding wire on each section of the cable tray to improve the reliability of the cable tray grounding, reduce the induced current generated on the cable tray, and reduce the heating loss;

[0018] 4. The cable tray is set in layers, and the three-phase power cables are laid in layers on the cable tray, which reduces the induced current generated on the cable shielding layer. At the same time, after the cables are arranged in two layers, the gap between the cables becomes larger, and the heat dissipation effect is enhanced under the ventilation state;

[0019] 5. Avoid the generation of eddy current loss during the rolling process, improve the system power factor. During steel rolling, the power factor cos￠ is above 0.98, the daily average power factor cos￠ is about 0.9, and the voltage fluctuation of the 10KV system is within 400V, ensuring the power supply quality and the stable operation of production. Description of the Drawings

[0020] Figure 1 It is a schematic diagram of the construction method and system for preventing the cables of the dynamic compensation system from heating and eddy current loss. Detailed Implementation Modes

[0021] The present invention will be described in detail below in conjunction with the accompanying drawings of the specification. However, it should be noted that the implementation of the present invention is not limited to the following embodiments.

[0022] The following embodiments are implemented on the premise of the technical solution of the present invention, and detailed implementation manners and specific operation processes are given. However, the protection scope of the present invention is not limited to the following embodiments. The methods used in the following embodiments are all conventional methods unless otherwise specified.

[0023]

Embodiment 1

[0024] See Figure 1 , a system for preventing cable heating and eddy current loss in a dynamic compensation system, including an SVC dynamic reactive power compensation device and a high-voltage cabinet. The high-voltage cabinet is used to provide three-phase AC power of A, B, and C for the SVC dynamic reactive power compensation device. The SVC dynamic reactive power compensation device and the high-voltage cabinet are connected by three-phase power cables of A, B, and C, and the power cables are laid through a cable tray.

[0025] The construction method for preventing cable heating and eddy current loss in a dynamic compensation system includes:

[0026] S1. Replace the original semi-closed iron bridge with an aluminum alloy trapezoidal bridge. Since aluminum metal is non-ferromagnetic, when the SVC dynamic reactive power compensation device is fully put into operation, eddy current heating is reduced. Since the replaced bridge is a trapezoidal bridge, the heat dissipation effect is improved under the ventilation state.

[0027] S2. Change the grounding of the original high-voltage cabinet end and the SVC dynamic reactive power compensation device end of the single-core cable to grounding at only the high-voltage cabinet end, reducing the induced voltage difference generated by the shielding layer of the single-core cable and avoiding the generation of circulating current in the cable shielding layer, thereby reducing the heating loss.

[0028] S3. After replacing the cable tray, install a grounding wire on each section of the cable tray to improve the reliability of the cable tray grounding, reduce the induced current generated on the cable tray, and reduce the heating loss.

[0029] S4. Change the placement method of the cables. Change the original random placement of the cables on the same layer of the cable tray to a layered setting of the cable tray, including upper, middle, and lower layers. The three-phase power cables of A, B, and C are respectively laid in the cable trays of the upper, middle, and lower layers, increasing the heat dissipation area and reducing the induced current generated on the cable shielding layer. After the three-phase power cables of A, B, and C are changed to be placed in three layers, the gap between the cables becomes larger, and the heat dissipation effect is enhanced under the ventilation state.

[0030] The cable tray of the present invention adopts an aluminum alloy trapezoidal tray to avoid eddy current loss. When the SSVC dynamic reactive power compensation device is fully put into operation, it reduces eddy current heating. At the same time, due to the trapezoidal tray, the heat dissipation effect of the cable and the cable tray is improved under the ventilation condition; the high-voltage cabinet adopts a method of grounding with a single-core cable while the SVC dynamic reactive power compensation device does not need to be grounded, which reduces the induced voltage difference generated by the shielding layer of the single-core cable and avoids the generation of circulating current in the cable shielding layer, thereby reducing the heating loss; a grounding wire is installed on each section of the cable tray to improve the grounding reliability of the cable tray, reduce the induced current generated on the cable tray, and reduce the heating loss; the cable tray is arranged in layers, and the three-phase power cables are laid in layers on the cable tray, which reduces the induced current generated on the cable shielding layer. At the same time, after the cables are arranged in two layers, the gap between the cables becomes larger, and the heat dissipation effect is enhanced under the ventilation condition; it avoids the generation of eddy current loss during the rolling process, improves the system power factor, the power factor cos￠ is above 0.98 during rolling, the daily average power factor cos￠ is about 0.9, and the voltage fluctuation of the 10KV system is within 400V, ensuring the power supply quality and the stable operation of production.

Claims

1. A construction method for preventing heating and eddy current loss of cables in a dynamic compensation system, characterized in that: Specifically include: S1. The cable tray adopts aluminum alloy ladder-shaped tray; S2. Install ground wire at the cable tray connection; S3. Use a single-core cable to ground the high-voltage cabinet, and the SVC dynamic reactive power compensation device does not need to be grounded; S4. Three-phase power cables shall be laid in layers.

2. A construction method for preventing heating and eddy current loss of cables in a dynamic compensation system according to claim 1, characterized in that: In S4, the cable trays are arranged in layers, and the A, B, and C three-phase power cables are laid in the cable trays on different layers.

3. A system for preventing heating and eddy current loss of cables in a dynamic compensation system for implementing the construction method described in claim 1 or 2, characterized in that: It includes an SVC dynamic reactive power compensation device and a high-voltage cabinet. The high-voltage cabinet is used to provide the SVC dynamic reactive power compensation device with A, B, C three-phase AC power supply. The SVC dynamic reactive power compensation device and the high-voltage cabinet are connected by A, B, C three-phase power cables.

4. According to the system for preventing heating and eddy current loss of the dynamic compensation system cable as described in claim 3, the three-phase power cables A, B, and C are laid by a cable tray.

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