Conductor and ground wire de-icing circuit suitable for live-line ground wire de-icing of power grid transmission line

Abstract

A conductor and ground wire de-icing circuit suitable for live-line de-icing of a power grid transmission line, relating to the technical field of de-icing circuits for power grid transmission lines. A phase-A bus, a phase-B bus, and a phase-C bus are respectively connected to a phase-A conductor, a phase-B conductor, and a phase-C conductor, and respective induced voltage suppression circuits and respective overvoltage protection circuits are arranged on the phase-A bus, the phase-B bus, and the phase-C bus. The induced voltage suppression circuits reduce an induced voltage on the power grid transmission line and limit the induced voltage within an insulation level of a direct-current side of a de-icing power supply. The overvoltage protection circuits reduce a lightning surge intrusion-caused overvoltage on the transmission line, disconnection of a de-icing loop, and a resonance-caused overvoltage that may occur in a de-icing system. Hence, the technical problem that existing transmission line de-icing apparatuses have poor induced voltage suppression and overvoltage protection performance in de-icing loops is solved.

Description

De-icing circuit for ground wires suitable for uninterrupted de-icing of power transmission lines

[0001] This application claims priority to Chinese Patent Application No. 202510063656.6, filed on January 15, 2025, entitled "A Conductor-Ground Wire De-icing Circuit for Uninterrupted De-icing of Power Grid Transmission Lines", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to the field of de-icing circuit technology for power grid transmission lines, and more particularly to a conductor de-icing circuit suitable for de-icing the ground wire of power grid transmission lines without power interruption. Background Technology

[0003] Overhead transmission lines are the main transmission channels for long-distance power transmission and are crucial equipment for ensuring the safe operation of the power grid. During rainy or snowy weather, the conductors and ground wires of transmission lines are prone to icing, causing power outages or tripping. Severe icing of the conductors and ground wires can lead to tower collapse and line breakage, seriously threatening the safe operation of the power grid. Therefore, timely de-icing of the conductors and ground wires of transmission lines is an important means of ensuring the safe operation of the power grid.

[0004] Existing transmission line de-icing devices mainly include DC de-icing devices using grid-commutated converters, DC de-icing devices using full-bridge modular multilevel converters, DC de-icing devices using fully controlled current source converters, low-frequency de-icing devices using variable frequency current sources, and uncontrolled DC de-icing devices using diode rectification. The insulation level of the de-icing device is usually much lower than that of the de-icing line. Lightning surge overvoltages caused by lightning strikes on the de-icing line can endanger the safety of the de-icing device. Resonant overvoltages in the de-icing system and operational overvoltages caused by line breaks also require protection. Simultaneously, induced voltages and currents in the de-icing circuit also need to be suppressed. Existing transmission line de-icing devices have poor performance in suppressing induced voltages and protecting against overvoltages in the de-icing circuit. How to improve the performance of induced voltage suppression and overvoltage protection in the de-icing circuit of transmission line conductors and ground wires is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] This invention provides a ground wire de-icing circuit suitable for uninterrupted de-icing of ground wires in power grid transmission lines, which solves the technical problem that existing transmission line de-icing devices have poor performance in suppressing induced voltage and protecting against overvoltage in the de-icing circuit.

[0006] In view of this, the present invention provides a conductor-to-ground wire de-icing circuit suitable for uninterrupted de-icing of ground wires in power grid transmission lines, including a de-icing power supply, an induced voltage suppression circuit, an overvoltage protection circuit, an A-phase busbar, a B-phase busbar, a C-phase busbar, an A-phase conductor, a B-phase conductor, a C-phase conductor, and a ground wire;

[0007] The ice-melting power supply is used to convert AC power to DC power, and the DC side of the ice-melting power supply has no grounding point;

[0008] The induced voltage suppression circuit includes a first resistor, a second resistor, and a capacitor. The second resistor and the capacitor are connected in series and then in parallel with the first resistor. One end of the first resistor is connected to one end of the second resistor, and the other end of the first resistor is grounded. The other end of the second resistor is connected to one end of the capacitor, and the other end of the capacitor is grounded with the ground terminal of the first resistor.

[0009] The overvoltage protection circuit includes a zinc oxide surge arrester and a protective gap, which are connected in parallel and share a common ground at one end.

[0010] A first isolating switch and a second isolating switch are connected in parallel to one DC output terminal of the ice-melting power supply, and a third isolating switch and a fourth isolating switch are connected in parallel to the other DC output terminal of the ice-melting power supply.

[0011] The first disconnecting switch is connected to one end of the A-phase busbar, and the other end of the A-phase busbar is connected to one end of the A-phase conductor. The A-phase busbar is equipped with an induced voltage suppression circuit and an overvoltage protection circuit.

[0012] The second disconnecting switch is connected to one end of the B-phase busbar, and the other end of the B-phase busbar is connected to one end of the B-phase conductor. The B-phase busbar is equipped with an induced voltage suppression circuit and an overvoltage protection circuit.

[0013] The third disconnecting switch is connected to one end of the B-phase busbar;

[0014] The fourth disconnecting switch is connected to one end of the C-phase busbar, and the other end of the C-phase busbar is connected to one end of the C-phase conductor. The C-phase busbar is equipped with an induced voltage suppression circuit and an overvoltage protection circuit.

[0015] The other end of phase A conductor is connected to the other end of phase B conductor via the fifth disconnecting switch. The other end of phase B conductor is connected to the other end of phase C conductor via the sixth disconnecting switch. Phase A conductor is connected to ground via the seventh disconnecting switch. Phase C conductor is connected to ground via the eighth disconnecting switch.

[0016] Optionally, the other end of the A-phase busbar is connected to one end of the A-phase conductor through a first de-icing circuit disconnect switch, the other end of the B-phase busbar is connected to one end of the B-phase conductor through a second de-icing circuit disconnect switch, and the other end of the C-phase busbar is connected to one end of the C-phase conductor through a third de-icing circuit disconnect switch.

[0017] Optionally, the connection terminals of the first de-icing line disconnect switch and the A-phase busbar, the connection terminals of the second de-icing line disconnect switch and the B-phase busbar, and the connection terminals of the third de-icing line disconnect switch and the C-phase busbar are respectively grounded through de-icing busbar grounding switches.

[0018] Optionally, the two DC output terminals of the ice-melting power supply are grounded through DC pole bus grounding switches.

[0019] Optionally, the value of the second resistor in the induced voltage suppression circuit is:

[0020] Among them, R C is the resistance value of the second resistor, k is a coefficient, L is the equivalent inductance value of the AC side of the ice-melting power supply, and C is the capacitance value.

[0021] Optionally, the capacitance value is taken as 1.0 to 3.0 times the total capacitance to ground of the conductor and ground wire in the same tower section as the uninterrupted power supply section in the ice melting line where the capacitor is located, and the coefficient k ranges from 1.0 to 2.0.

[0022] Optionally, the value of the first resistor is: R H =U dc / I ds

[0023] Among them, R H U is the resistance value of the first resistor. dc I is the rated voltage of the busbar connected to the first resistor. ds This is the discharge current of the first resistor.

[0024] Optionally, the rated voltage of the zinc oxide surge arrester in the overvoltage protection circuit is 1.05 to 1.10 times the maximum continuous operating voltage at the installation location of the zinc oxide surge arrester.

[0025] Optionally, both ends of phase A conductor, both ends of phase B conductor, and both ends of phase C conductor are grounded through conductor grounding switches.

[0026] Optionally, the ground wire can be grounded through a grounding switch.

[0027] As can be seen from the above technical solutions, the embodiments of the present invention have the following advantages:

[0028] This invention provides a conductor-to-ground wire de-icing circuit suitable for uninterrupted de-icing of power grid transmission lines. Phase A, Phase B, and Phase C busbars are connected to Phase A conductors, Phase B conductors, and Phase C conductors, respectively. Induced voltage suppression circuits and overvoltage protection circuits are respectively installed on Phase A, Phase B, and Phase C busbars. The induced voltage suppression circuit reduces the induced voltage of the power grid transmission line, limiting it to the insulation level of the DC side of the de-icing power supply. The overvoltage protection circuit reduces overvoltage caused by lightning surges, de-icing circuit disconnection, and potential resonant overvoltage in the de-icing system. This invention solves the technical problem of poor induced voltage suppression and overvoltage protection performance in existing power grid transmission line de-icing devices.

[0029] Meanwhile, the ground wire de-icing circuit provided by this invention, which is suitable for de-icing the ground wire of power grid transmission lines without interrupting power supply, does not require the power grid transmission lines to be shut down before de-icing the ground wire can be carried out, thus solving the technical problem that existing de-icing devices require the power grid transmission lines to be shut down before de-icing the ground wire can be carried out. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 is a circuit diagram of a ground wire de-icing circuit suitable for uninterrupted de-icing of power grid transmission lines, provided in an embodiment of the present invention. Detailed Implementation

[0032] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] For ease of understanding, please refer to Figure 1. This invention provides an embodiment of a conductor-to-ground wire de-icing circuit suitable for uninterrupted de-icing of ground wires in power grid transmission lines, including a de-icing power supply 1, an induced voltage suppression circuit 2, an overvoltage protection circuit 3, an A-phase bus MA, a B-phase bus MB, a C-phase bus MC, an A-phase conductor DA, a B-phase conductor DB, a C-phase conductor DC, and a ground wire LD.

[0034] The ice-melting power supply 1 is used to convert AC power to DC power. The DC side of the ice-melting power supply has no grounding point.

[0035] Induced voltage suppression circuit 2 includes a first resistor R H Second resistor R C With capacitor C, second resistor R C After being connected in series with capacitor C, it is connected to the first resistor R. H Parallel connection, first resistor R H One end is connected to the second resistor R C One end is connected to the first resistor R. H The other end is grounded, and the second resistor R C The other end is connected to one end of capacitor C, and the other end of capacitor C is connected to the first resistor R. H The grounding terminal is common to the ground.

[0036] The overvoltage protection circuit 3 includes a zinc oxide surge arrester F and a protective gap G, which are connected in parallel and share a common ground at one end.

[0037] A first isolating switch S1 and a second isolating switch S2 are connected in parallel to one DC output terminal of the ice-melting power supply 1, and a third isolating switch S3 and a fourth isolating switch S4 are connected in parallel to the other DC output terminal of the ice-melting power supply 1.

[0038] The first disconnecting switch S1 is connected to one end of the A-phase busbar MA, and the other end of the A-phase busbar MA is connected to one end of the A-phase conductor DA. The A-phase busbar MA is equipped with an induced voltage suppression circuit 2 and an overvoltage protection circuit 3.

[0039] The second disconnecting switch S2 is connected to one end of the B-phase busbar MB, and the other end of the B-phase busbar MB is connected to one end of the B-phase conductor DB. The B-phase busbar DB is connected to an induced voltage suppression circuit 2 and an overvoltage protection circuit 3.

[0040] The third disconnector switch S3 is connected to one end of the B-phase busbar MB.

[0041] The fourth disconnecting switch S4 is connected to one end of the C-phase busbar MC, and the other end of the C-phase busbar MC is connected to one end of the C-phase conductor DC. The C-phase busbar MC is equipped with an induced voltage suppression circuit 2 and an overvoltage protection circuit 3.

[0042] The other end of phase A conductor DA is connected to the other end of phase B conductor DB through the fifth disconnecting switch S5. The other end of phase B conductor DB is connected to the other end of phase C conductor DC through the sixth disconnecting switch S6. Phase A conductor DA is connected to ground wire LD through the seventh disconnecting switch S7. Phase C conductor DC is connected to ground wire LD through the eighth disconnecting switch S8.

[0043] It should be noted that, as shown in Figure 1, the induced voltage suppression circuit 2 includes a first resistor R. H Second resistor R C With capacitor C, second resistor R C The capacitor C is connected in series with the first resistor R in parallel. H One end is connected to the second resistor R C One end is connected to the first resistor R. H The other end is grounded, and the second resistor R C The other end is connected to one end of capacitor C, and the other end of capacitor is connected to the first resistor R. H The grounding terminals are common to the ground. Phase A bus MA, Phase B bus MB, and Phase C bus MC are respectively connected through the first resistor R of the induced voltage suppression circuit 2. H Second resistor R CThe common terminal is connected to the induced voltage suppression circuit 2. The induced voltage suppression circuit 2 is used to reduce the induced voltage of the power grid transmission line to limit the induced voltage within the insulation level of the DC side of the de-icing power supply. The first resistor R of the induced voltage suppression circuit 2... H Used to discharge induced charge in DC lines. When the DC line melts ice, there is an ion flow field where charge accumulates, which is discharged through the first resistor R. H Discharge, clamp voltage.

[0044] In one embodiment, the second resistor R in the induced voltage suppression circuit C The value can be:

[0045] Among them, R C is the resistance value of the second resistor, k is a coefficient, L is the equivalent inductance value of the AC side of the ice-melting power supply, and C is the capacitance value.

[0046] The capacitance value of capacitor C is taken as 1.0 to 3.0 times the total capacitance to ground of the conductor and ground wire in the same tower section as the uninterrupted power supply section in the ice melting line where capacitor C is located, and the coefficient k ranges from 1.0 to 2.0.

[0047] First resistor R H The value of is: R H =U dc / I ds

[0048] Among them, R H U is the resistance value of the first resistor. dc I is the rated voltage of the busbar connected to the first resistor. ds The discharge current of the first resistor is 10mA-50mA, and the first resistor R is... H It is less than the equivalent resistance of the ion flow field of the conductor section on the same tower as the live-line in the de-icing circuit, and less than the total resistance of the insulators on the ground wire section on the same tower as the live-line in the de-icing circuit. R H Values ​​are taken in the range of 50kΩ-1000kΩ.

[0049] The overvoltage protection circuit 3 includes a zinc oxide surge arrester F and a protective gap G. The A-phase bus MA, B-phase bus MB, and C-phase bus MC are connected to the overvoltage protection circuit 3 via the common terminal of the zinc oxide surge arrester F and the protective gap G in the overvoltage protection circuit 2. The overvoltage protection circuit 3 is used to reduce overvoltages caused by lightning surges, line breaks in the de-icing circuit, and resonant overvoltages that may occur in the de-icing system. The protective gap G is primarily used to prevent resonance and protect the zinc oxide surge arrester F, avoiding damage to it. In one embodiment, the rated voltage of the zinc oxide surge arrester F in the overvoltage protection circuit 3 is 1.05 to 1.10 times the maximum continuous operating voltage at the installation location of the zinc oxide surge arrester F. The length of the protective gap G should preferably be selected according to the gap corresponding to the 90% operating impulse protection level and the 90% lightning impulse protection level of the surge arrester.

[0050] In one embodiment, the other end of phase A busbar MA is connected to one end of phase A conductor DA via a first de-icing line isolating switch S9; the other end of phase B busbar MB is connected to one end of phase B conductor DB via a second de-icing line isolating switch S10; and the other end of phase C busbar MC is connected to one end of phase C conductor DC via a third de-icing line isolating switch S11. The connection terminals of the first de-icing line isolating switch S9 and phase A busbar MA, the second de-icing line isolating switch S10 and phase B busbar MB, and the third de-icing line isolating switch S11 and phase C busbar MC are respectively grounded via a de-icing busbar grounding switch S12. When phase A busbar MA, phase B busbar MB, and phase C busbar MC require inspection and maintenance, the de-icing busbar grounding switch S12 is closed to ensure personnel safety. The two DC output terminals of the de-icing power supply 1 are grounded through DC bus grounding switch S13. DC bus grounding switch S13 is closed when isolating switches S1, S2, S3, and S4 are open. DC bus grounding switch S13 is closed when the de-icing power supply 1 needs inspection or maintenance to ensure personnel safety. The two ends of phase A conductor DA, the two ends of phase B conductor DB, and the two ends of phase C conductor DC are grounded through conductor grounding switch S14. Conductor grounding switch S14 is closed when phase A conductor DA, phase B conductor DB, and phase C conductor need inspection or maintenance to ensure personnel safety. The ground wire LD is grounded through grounding switch S15. Grounding switch S15 is closed when the ground wire is not de-icing to ensure that the operation of the transmission line is not affected.

[0051] This invention provides a conductor-to-ground wire de-icing circuit suitable for uninterrupted de-icing of power grid transmission lines. Phase A, Phase B, and Phase C busbars are connected to Phase A conductors, Phase B conductors, and Phase C conductors, respectively. Induced voltage suppression circuits and overvoltage protection circuits are respectively installed on Phase A, Phase B, and Phase C busbars. The induced voltage suppression circuit reduces the induced voltage of the power grid transmission line, limiting it to the insulation level of the DC side of the de-icing power supply. The overvoltage protection circuit reduces overvoltage caused by lightning surges, de-icing circuit disconnection, and potential resonant overvoltage in the de-icing system. This invention solves the technical problem of poor induced voltage suppression and overvoltage protection performance in existing power grid transmission line de-icing devices.

[0052] Meanwhile, the ground wire de-icing circuit provided by this invention, which is suitable for de-icing the ground wire of power grid transmission lines without interrupting power supply, does not require the power grid transmission lines to be shut down before de-icing the ground wire can be carried out, thus solving the technical problem that existing de-icing devices require the power grid transmission lines to be shut down before de-icing the ground wire can be carried out.

[0053] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A conductor-to-ground wire de-icing circuit suitable for uninterrupted de-icing of ground wires in power grid transmission lines, characterized in that, This includes a de-icing power supply, an induced voltage suppression circuit, an overvoltage protection circuit, an A-phase busbar, a B-phase busbar, a C-phase busbar, an A-phase conductor, a B-phase conductor, a C-phase conductor, and a ground wire; The ice-melting power supply is used to convert AC power to DC power, and the DC side of the ice-melting power supply has no grounding point; The induced voltage suppression circuit includes a first resistor, a second resistor, and a capacitor. The second resistor and the capacitor are connected in series and then in parallel with the first resistor. One end of the first resistor is connected to one end of the second resistor, and the other end of the first resistor is grounded. The other end of the second resistor is connected to one end of the capacitor, and the other end of the capacitor is grounded with the ground terminal of the first resistor. The overvoltage protection circuit includes a zinc oxide surge arrester and a protective gap, which are connected in parallel and share a common ground at one end. A first isolating switch and a second isolating switch are connected in parallel to one DC output terminal of the ice-melting power supply, and a third isolating switch and a fourth isolating switch are connected in parallel to the other DC output terminal of the ice-melting power supply. The first disconnecting switch is connected to one end of the A-phase busbar, and the other end of the A-phase busbar is connected to one end of the A-phase conductor. The A-phase busbar is equipped with an induced voltage suppression circuit and an overvoltage protection circuit. The second disconnecting switch is connected to one end of the B-phase busbar, and the other end of the B-phase busbar is connected to one end of the B-phase conductor. The B-phase busbar is equipped with an induced voltage suppression circuit and an overvoltage protection circuit. The third disconnecting switch is connected to one end of the B-phase busbar; The fourth disconnecting switch is connected to one end of the C-phase busbar, and the other end of the C-phase busbar is connected to one end of the C-phase conductor. The C-phase busbar is equipped with an induced voltage suppression circuit and an overvoltage protection circuit. The other end of phase A conductor is connected to the other end of phase B conductor via the fifth disconnecting switch. The other end of phase B conductor is connected to the other end of phase C conductor via the sixth disconnecting switch. Phase A conductor is connected to ground via the seventh disconnecting switch. Phase C conductor is connected to ground via the eighth disconnecting switch.

2. The conductor-to-ground wire de-icing circuit for uninterrupted de-icing of power transmission lines according to claim 1, characterized in that, The other end of phase A busbar is connected to one end of phase A conductor via the first de-icing circuit disconnect switch; the other end of phase B busbar is connected to one end of phase B conductor via the second de-icing circuit disconnect switch; and the other end of phase C busbar is connected to one end of phase C conductor via the third de-icing circuit disconnect switch.

3. The conductor-to-ground wire de-icing circuit for uninterrupted de-icing of power transmission lines according to claim 2, characterized in that, The connection terminals of the first de-icing line isolating switch and the A-phase busbar, the second de-icing line isolating switch and the B-phase busbar, and the third de-icing line isolating switch and the C-phase busbar are respectively grounded through the de-icing busbar grounding switch.

4. The conductor-to-ground wire de-icing circuit for uninterrupted de-icing of power transmission lines according to claim 1, characterized in that, The two DC output terminals of the ice-melting power supply are grounded through DC pole bus grounding switches.

5. The conductor-to-ground wire de-icing circuit according to any one of claims 1-4, applicable to uninterrupted de-icing of ground wires in power grid transmission lines, characterized in that, The value of the second resistor in the induced voltage suppression circuit is: Among them, R C is the resistance value of the second resistor, k is a coefficient, L is the equivalent inductance value of the AC side of the ice-melting power supply, and C is the capacitance value.

6. The conductor-to-ground wire de-icing circuit for uninterrupted de-icing of power transmission lines according to claim 5, characterized in that, The capacitance value is taken as 1.0 to 3.0 times the total capacitance to ground of the conductors and ground wires in the same tower section of the de-icing line where the capacitor is located and the uninterrupted power supply section. The coefficient k ranges from 1.0 to 2.

0.

7. The conductor-to-ground wire de-icing circuit for uninterrupted de-icing of power transmission lines according to claim 5, characterized in that, The value of the first resistor is: R H =U dc / I ds Among them, R H U is the resistance value of the first resistor. dc I is the rated voltage of the busbar connected to the first resistor. ds This is the discharge current of the first resistor.

8. The conductor-to-ground wire de-icing circuit for uninterrupted de-icing of power transmission lines according to claim 1, characterized in that, The rated voltage of the zinc oxide surge arrester in the overvoltage protection circuit is 1.05 to 1.10 times the maximum continuous operating voltage of the zinc oxide surge arrester at the installation location.

9. The conductor-to-ground wire de-icing circuit for uninterrupted de-icing of power transmission lines according to claim 1, characterized in that, Both ends of phase A conductor, both ends of phase B conductor, and both ends of phase C conductor are grounded through conductor grounding switches.

10. The conductor-to-ground wire de-icing circuit according to claim 1, applicable to uninterrupted de-icing of ground wires in power grid transmission lines, characterized in that, The ground wire is grounded through a grounding switch.

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