Ground wire ice melting circuit for melting ice on power transmission line of power grid without power cut

Abstract

The invention discloses a ground wire ice melting circuit for melting ice on a power grid power transmission line without power outage, which is characterized in that an A-phase bus, a B-phase bus and a C-phase bus are respectively connected with an A-phase lead, a B-phase lead and a C-phase lead, and an induced voltage suppression circuit and an overvoltage protection circuit are respectively arranged on the A-phase bus, the B-phase bus and the C-phase bus; the induced voltage suppression circuit reduces the induced voltage of the power transmission line of the power grid and limits the induced voltage within the insulation level of the direct current side of the ice melting power supply, and the overvoltage protection circuit reduces the lightning invasion wave overvoltage of the power transmission line, the disconnection of an ice melting loop and the possible resonance overvoltage of the ice melting system. The technical problem that an existing power transmission line ice melting device is poor in induced voltage suppression and overvoltage protection performance in an ice melting loop is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of ice-melting circuits for power transmission lines of power grids, and in particular to a ground wire ice-melting circuit for non-stop ice-melting of power transmission lines of power grids. Background Art

[0002] Overhead transmission lines are the main transmission channels for long-distance power transmission and are important equipment for ensuring the safe operation of power grids. In rainy and snowy weather, the ground wires of transmission lines are prone to ice, causing the transmission lines to shut down or trip. When the ground wires of transmission lines are severely covered with ice, it will cause the transmission line towers to collapse and the lines to break, seriously threatening the safe operation of the power grid. Therefore, timely deicing of the ground wires of transmission lines is an important means to ensure the safe operation of the power grid.

[0003] Existing transmission line ice melting devices mainly include grid phase-commutated converter DC ice melting devices, full-bridge modular multi-level converter DC ice melting devices, fully controlled device current source converter DC ice melting devices, variable frequency current source low-frequency ice melting devices, and diode rectifier uncontrolled DC ice melting devices. The insulation level of the ice melting device is usually much lower than that of the ice melting line. The lightning intrusion wave overvoltage caused by lightning striking the ice melting line may endanger the safety of the ice melting device. The resonant overvoltage of the ice melting system and the operating overvoltage caused by the disconnection of the ice melting line also need to be protected. At the same time, the induced voltage and current in the ice melting circuit also need to be suppressed. The existing transmission line ice melting devices have poor performance in suppressing the induced voltage and overvoltage protection in the ice melting circuit. How to improve the induced voltage suppression and overvoltage protection performance in the transmission line ground wire ice melting circuit is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0004] The invention provides a ground wire de-icing circuit for power grid transmission lines to melt de-ices without power outages, and is used to solve the technical problem that the existing de-icing devices for transmission lines have poor performance in suppressing induced voltage in de-icing loops and protecting against overvoltage.

[0005] In view of this, the present invention provides a ground wire ice melting circuit for non-stop ice melting of power transmission lines of a power grid, comprising an ice melting power supply, an induction 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;

[0006] The ice-melting power supply is used to convert AC power into DC power. There is no grounding point on the DC side of the ice-melting power supply.

[0007] The induced voltage suppression circuit includes a first resistor, a second resistor and a capacitor, the second resistor is connected in series with the capacitor and then connected in parallel with the first resistor, one end of the first resistor is connected to one end of the second resistor, 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 to the ground end of the first resistor;

[0008] The overvoltage protection circuit includes a zinc oxide lightning arrester and a protection gap, wherein the zinc oxide lightning arrester and the protection gap are connected in parallel and one end of the zinc oxide lightning arrester and the protection gap are grounded;

[0009] A first isolating switch and a second isolating switch are connected in parallel to one DC output end of the ice-melting power supply, and a third isolating switch and a fourth isolating switch are connected in parallel to another DC output end of the ice-melting power supply;

[0010] The first isolating switch is connected to one end of the A-phase busbar, the other end of the A-phase busbar is connected to one end of the A-phase conductor, and the A-phase busbar is connected to an induced voltage suppression circuit and an overvoltage protection circuit;

[0011] The second isolating switch is connected to one end of the B-phase busbar, the other end of the B-phase busbar is connected to one end of the B-phase conductor, and the B-phase busbar is connected to an induced voltage suppression circuit and an overvoltage protection circuit;

[0012] The third isolating switch is connected to one end of the B-phase busbar;

[0013] The fourth isolating switch is connected to one end of the C-phase busbar, the other end of the C-phase busbar is connected to one end of the C-phase conductor, and the C-phase busbar is connected to an induced voltage suppression circuit and an overvoltage protection circuit;

[0014] The other end of the A-phase wire is connected to the other end of the B-phase wire through the fifth isolating switch, the other end of the B-phase wire is connected to the other end of the C-phase wire through the sixth isolating switch, the A-phase wire is connected to the ground wire through the seventh isolating switch, and the C-phase wire is connected to the ground wire through the eighth isolating switch.

[0015] Optionally, the other end of the A-phase busbar is connected to one end of the A-phase conductor through a first ice-melting line isolating switch, the other end of the B-phase busbar is connected to one end of the B-phase conductor through a second ice-melting line isolating switch, and the other end of the C-phase busbar is connected to one end of the C-phase conductor through a third ice-melting line isolating switch.

[0016] Optionally, the connection end between the first ice-melting line disconnector and the A-phase bus, the connection end between the second ice-melting line disconnector and the B-phase bus, and the connection end between the third ice-melting line disconnector and the C-phase bus are grounded through the ice-melting bus grounding switch respectively.

[0017] Optionally, two DC output terminals of the ice-melting power supply are grounded through DC bus grounding switches respectively.

[0018] Optionally, the value of the second resistor in the induced voltage suppression circuit is:

[0019]

[0020] in, is the resistance of the second resistor, k is the coefficient, L is the equivalent inductance of the AC side of the ice-melting power supply, and C is the capacitance of the capacitor.

[0021] Optionally, the capacitance of the capacitor is 1.0 to 3.0 times the total capacitance of the conductor and ground wire to the ground in the same tower section as the non-stop power 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:

[0023]

[0024] in, is the resistance value of the first resistor, is the rated voltage of the busbar connected to the first resistor, is the discharge current of the first resistor.

[0025] Optionally, the rated voltage of the zinc oxide lightning arrester in the overvoltage protection circuit is 1.05 to 1.10 times the maximum continuous operating voltage of the installation location of the zinc oxide lightning arrester.

[0026] Optionally, both ends of the A-phase wire, both ends of the B-phase wire and both ends of the C-phase wire are grounded through wire grounding switches respectively.

[0027] Optionally, the ground wire is grounded via a ground wire grounding switch.

[0028] It can be seen from the above technical solutions that the embodiments of the present invention have the following advantages:

[0029] The present invention provides a ground wire de-icing circuit for non-stop de-icing of power grid transmission lines. An A-phase bus, a B-phase bus and a C-phase bus are respectively connected to an A-phase conductor, a B-phase conductor and a C-phase conductor. An induced voltage suppression circuit and an overvoltage protection circuit are respectively arranged on the A-phase bus, the B-phase bus and the C-phase bus. The induced voltage suppression circuit reduces the induced voltage of the power grid transmission line and limits the induced voltage within the insulation level of the DC side of the de-icing power supply. The overvoltage protection circuit reduces the overvoltage of the lightning intrusion wave of the transmission line, the disconnection of the de-icing circuit and the resonant overvoltage that may occur in the de-icing system, thereby solving the technical problem that the existing de-icing device for the transmission line has poor performance in suppressing the induced voltage and protecting against overvoltage in the de-icing circuit.

[0030] At the same time, the ground wire de-icing circuit provided by the present invention for non-stop de-icing of power grid transmission lines does not require the power grid transmission lines to be shut down to de-ice the ground wires, thus solving the technical problem that the existing de-icing devices require the transmission lines to be shut down to de-ice the ground wires. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 The present invention provides a circuit schematic diagram of a ground wire de-icing circuit for non-stop de-icing of power transmission lines in a power grid, provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] For easier understanding, see Figure 1 The present invention provides an embodiment of a ground wire de-icing circuit for non-stop de-icing of power transmission lines of a power grid, comprising a de-icing power supply 1, an induced voltage suppression circuit 2, an overvoltage protection circuit 3, an A-phase busbar MA, a B-phase busbar MB, a C-phase busbar MC, an A-phase conductor DA, a B-phase conductor DB, a C-phase conductor DC and a ground wire LD.

[0035] The ice-melting power supply 1 is used to convert alternating current into direct current, and the direct current side of the ice-melting power supply has no grounding point.

[0036] The induced voltage suppression circuit 2 includes a first resistor , the second resistor and capacitor C, the second resistor After being connected in series with capacitor C and the first resistor Parallel, first resistor One end of the second resistor One end of the first resistor is connected The other end of the second resistor is grounded. The other end of the capacitor C is connected to one end of the first resistor The ground terminals are connected to the common ground.

[0037] The overvoltage protection circuit 3 includes a zinc oxide lightning arrester F and a protection gap G. The zinc oxide lightning arrester F and the protection gap G are connected in parallel and have one end connected to a common ground.

[0038] A first isolating switch S1 and a second isolating switch S2 are connected in parallel to one DC output end 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 end of the ice-melting power supply 1 .

[0039] The first isolating switch S1 is connected to one end of the A-phase busbar MA, the other end of the A-phase busbar MA is connected to one end of the A-phase conductor DA, and the A-phase busbar MA is connected to an induced voltage suppression circuit 2 and an overvoltage protection circuit 3.

[0040] The second isolating switch S2 is connected to one end of the B-phase busbar MB, the other end of the B-phase busbar MB is connected to one end of the B-phase conductor DB, and the B-phase busbar DB is connected to an induced voltage suppression circuit 2 and an overvoltage protection circuit 3.

[0041] The third isolating switch S3 is connected to one end of the B-phase busbar MB.

[0042] The fourth isolating switch S4 is connected to one end of the C-phase bus MC, the other end of the C-phase bus MC is connected to one end of the C-phase conductor DC, and the C-phase bus MC is connected to an induced voltage suppression circuit 2 and an overvoltage protection circuit 3 .

[0043] The other end of the A-phase conductor DA is connected to the other end of the B-phase conductor DB through the fifth isolating switch S5, the other end of the B-phase conductor DB is connected to the other end of the C-phase conductor DC through the sixth isolating switch S6, the A-phase conductor DA is connected to the ground wire LD through the seventh isolating switch S7, and the C-phase conductor DC is connected to the ground wire LD through the eighth isolating switch S8.

[0044] It should be noted that if Figure 1 As shown, the induced voltage suppression circuit 2 includes a first resistor , the second resistor and capacitor C, the second resistor After being connected in series with the capacitor C, it is connected in parallel with the first resistor. One end of the second resistor One end of the first resistor is connected The other end of the second resistor is grounded. The other end of the capacitor is connected to one end of the capacitor C, and the other end of the capacitor is connected to the first resistor The A-phase busbar MA, the B-phase busbar MB and the C-phase busbar MC are respectively connected through the first resistor of the induction voltage suppression circuit 2 and the second resistor The common end of the induction voltage suppression circuit 2 is connected to the induction voltage suppression circuit 2. The induction voltage suppression circuit 2 is used to reduce the induction voltage of the power transmission line of the power grid to limit the induction voltage to the insulation level of the DC side of the ice melting power supply. Used to discharge the induced charge of the DC line. When the DC line melts, there is an ion flow field charge accumulation, which passes through the first resistor Discharge, clamp voltage.

[0045] In one embodiment, the second resistor in the inductive voltage suppression circuit The value of is:

[0046]

[0047] in, is the resistance of the second resistor, k is the coefficient, L is the equivalent inductance of the AC side of the ice-melting power supply, and C is the capacitance of the capacitor.

[0048] The capacitance value of capacitor C is 1.0~3.0 times the total capacitance of the conductor and ground wire to the ground in the same tower section as the non-stop power section in the ice-melting line where capacitor C is located, and the coefficient k ranges from 1.0~2.0.

[0049] First resistor The value of is:

[0050]

[0051] in, is the resistance value of the first resistor, is the rated voltage of the busbar connected to the first resistor, is the discharge current of the first resistor, the range of the discharge current is 10mA-50mA, the first resistor It is smaller than the equivalent resistance of the ion flow field of the conductor section on the same tower as the non-stop power line in the ice melting circuit, and is smaller than the total resistance of the insulators on the ground wire section on the same tower as the non-stop power line in the ice melting circuit. The value is in the range of 50kΩ-1000kΩ.

[0052] The overvoltage protection circuit 3 includes a zinc oxide arrester F and a protection gap G. The A-phase busbar MA, the B-phase busbar MB and the C-phase busbar MC are respectively connected to the overvoltage protection circuit 3 through the common end of the zinc oxide arrester F and the protection gap G of the overvoltage protection circuit 2. The overvoltage protection circuit 3 is used to reduce the overvoltage of the lightning intrusion wave of the transmission line, the disconnection of the ice melting circuit and the resonant overvoltage that may occur in the ice melting system. Among them, the protection gap G is mainly used to prevent resonance and protect the zinc oxide arrester F to avoid damage to the zinc oxide arrester F. In one embodiment, the rated voltage of the zinc oxide arrester F in the overvoltage protection circuit 3 is 1.05 to 1.10 times the maximum continuous operating voltage of the zinc oxide arrester F installation position. The protection gap length of the protection gap G should be selected according to the gap corresponding to the 90% operating impulse protection level and the 90% lightning impulse protection level of the arrester.

[0053] In one embodiment, the other end of the A-phase busbar MA is connected to one end of the A-phase conductor DA through the first ice-melting line disconnector S9, the other end of the B-phase busbar MB is connected to one end of the B-phase conductor DB through the second ice-melting line disconnector S10, and the other end of the C-phase busbar MC is connected to one end of the C-phase conductor DC through the third ice-melting line disconnector S11. The connection end of the first ice-melting line disconnector S9 and the A-phase busbar MA, the connection end of the second ice-melting line disconnector S10 and the B-phase busbar MB, and the connection end of the third ice-melting line disconnector S11 and the C-phase busbar MC are grounded through the ice-melting busbar grounding switch S12 respectively. When the A-phase busbar MA, the B-phase busbar MB and the C-phase busbar MC need to be inspected and repaired, the ice-melting busbar grounding switch S12 is closed to ensure the safety of personnel. The two DC output terminals of the ice-melting power supply 1 are grounded through the DC bus grounding switch S13. When the isolating switches S1, S2, S3 and S4 are open, the DC bus grounding switch S13 is closed. When the ice-melting power supply 1 needs to be inspected and repaired, the DC bus grounding switch S13 is closed to ensure the safety of personnel. The two ends of the A-phase conductor DA, the two ends of the B-phase conductor DB and the two ends of the C-phase conductor DC are grounded through the conductor grounding switch S14 respectively. When the A-phase conductor DA, the B-phase conductor DB and the C-phase conductor need to be inspected and repaired, the conductor grounding switch S14 is closed to ensure the safety of personnel. The ground wire LD is grounded through the grounding switch S15. When the ground wire is not melting, the grounding switch S15 is closed to ensure that the operation of the transmission line is not affected.

[0054] The present invention provides a ground wire de-icing circuit for non-stop de-icing of power grid transmission lines. An A-phase bus, a B-phase bus and a C-phase bus are respectively connected to an A-phase conductor, a B-phase conductor and a C-phase conductor. An induced voltage suppression circuit and an overvoltage protection circuit are respectively arranged on the A-phase bus, the B-phase bus and the C-phase bus. The induced voltage suppression circuit reduces the induced voltage of the power grid transmission line and limits the induced voltage within the insulation level of the DC side of the de-icing power supply. The overvoltage protection circuit reduces the overvoltage of the lightning intrusion wave of the transmission line, the disconnection of the de-icing circuit and the resonant overvoltage that may occur in the de-icing system, thereby solving the technical problem that the existing de-icing device for the transmission line has poor performance in suppressing the induced voltage and protecting against overvoltage in the de-icing circuit.

[0055] At the same time, the ground wire de-icing circuit provided by the present invention for non-stop de-icing of power grid transmission lines does not require the power grid transmission lines to be shut down to de-ice the ground wires, thus solving the technical problem that the existing de-icing devices require the transmission lines to be shut down to de-ice the ground wires.

[0056] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A ground wire de-icing circuit for de-icing power transmission lines without power outages, characterized in that: It includes an ice melting power supply, an induction 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 into DC power. There is no grounding point on the DC side of the ice-melting power supply. The induced voltage suppression circuit includes a first resistor, a second resistor and a capacitor, the second resistor is connected in series with the capacitor and then connected in parallel with the first resistor, one end of the first resistor is connected to one end of the second resistor, 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 to the ground end of the first resistor; The overvoltage protection circuit includes a zinc oxide lightning arrester and a protection gap, the zinc oxide lightning arrester and the protection gap are connected in parallel and one end of the zinc oxide lightning arrester and the protection gap are grounded; A first isolating switch and a second isolating switch are connected in parallel to one DC output end 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 end of the ice-melting power supply; The first isolating switch is connected to one end of the A-phase busbar, the other end of the A-phase busbar is connected to one end of the A-phase conductor, and the A-phase busbar is connected to an induced voltage suppression circuit and an overvoltage protection circuit; The second isolating switch is connected to one end of the B-phase busbar, the other end of the B-phase busbar is connected to one end of the B-phase conductor, and the B-phase busbar is connected to an induced voltage suppression circuit and an overvoltage protection circuit; The third isolating switch is connected to one end of the B-phase busbar; The fourth isolating switch is connected to one end of the C-phase busbar, the other end of the C-phase busbar is connected to one end of the C-phase conductor, and the C-phase busbar is connected to an induced voltage suppression circuit and an overvoltage protection circuit; The other end of the A-phase wire is connected to the other end of the B-phase wire through the fifth isolating switch, the other end of the B-phase wire is connected to the other end of the C-phase wire through the sixth isolating switch, the A-phase wire is connected to the ground wire through the seventh isolating switch, and the C-phase wire is connected to the ground wire through the eighth isolating switch.

2. The ground wire de-icing circuit for de-icing power transmission lines without power outage according to claim 1, characterized in that: The other end of the A-phase busbar is connected to one end of the A-phase conductor through the first ice-melting line disconnector, the other end of the B-phase busbar is connected to one end of the B-phase conductor through the second ice-melting line disconnector, and the other end of the C-phase busbar is connected to one end of the C-phase conductor through the third ice-melting line disconnector.

3. The ground wire de-icing circuit for de-icing power transmission lines without power outage according to claim 2, characterized in that: The connection end of the first ice-melting line disconnector and the A-phase bus, the connection end of the second ice-melting line disconnector and the B-phase bus, and the connection end of the third ice-melting line disconnector and the C-phase bus are grounded through the ice-melting bus grounding switches respectively.

4. The ground wire de-icing circuit for de-icing power transmission lines without power outage according to claim 1, characterized in that: The two DC output terminals of the ice-melting power supply are grounded through DC bus grounding switches respectively.

5. The ground wire de-icing circuit for de-icing power transmission lines without power outage according to any one of claims 1 to 4, characterized in that: The value of the second resistor in the induced voltage suppression circuit is: in, is the resistance of the second resistor, k is the coefficient, L is the equivalent inductance of the AC side of the ice-melting power supply, and C is the capacitance of the capacitor.

6. The ground wire de-icing circuit for de-icing power transmission lines without power outage according to claim 5, characterized in that: The capacitance value of the capacitor is 1.0~3.0 times the total capacitance of the conductor and ground wire to the ground in the same tower section as the non-stop power section in the ice-melting line where the capacitor is located, and the coefficient k ranges from 1.0~2.

0.

7. The ground wire de-icing circuit for de-icing power transmission lines without power outage according to claim 5, characterized in that: The value of the first resistor is: in, is the resistance value of the first resistor, is the rated voltage of the busbar connected to the first resistor, is the discharge current of the first resistor.

8. The ground wire de-icing circuit for de-icing power transmission lines without power outage according to claim 1, characterized in that: The rated voltage of the zinc oxide lightning arrester in the overvoltage protection circuit is 1.05~1.10 times the maximum continuous operating voltage of the zinc oxide lightning arrester installation location.

9. The ground wire de-icing circuit for de-icing power transmission lines without power outage according to claim 1, characterized in that: Both ends of the A-phase conductor, both ends of the B-phase conductor, and both ends of the C-phase conductor are grounded through conductor grounding switches, respectively.

10. The ground wire de-icing circuit for de-icing power transmission lines without power outage according to claim 1, characterized in that: The ground wire is grounded through the ground wire grounding switch.

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