WO2021136286A1

WO2021136286A1 - System and method for melting ice on overhead line by using photovoltaic power generation

Info

Publication number: WO2021136286A1
Application number: PCT/CN2020/140967
Authority: WO
Inventors: 杨洋; 赵文超; 李铭志; 赵勇; 邓巍
Original assignee: 西安热工研究院有限公司
Priority date: 2019-12-30
Filing date: 2020-12-29
Publication date: 2021-07-08
Also published as: CN110932215A

Abstract

A system and method for melting ice on an overhead line by using photovoltaic power generation. The system comprises photovoltaic power generation units, a direct-current busbar for receiving power generated by the photovoltaic power generation units, a direct-current ice melting system connected to the direct-current busbar, and overhead power wires connected to the direct-current ice melting system; ice-melting short-circuit disconnectors mounted at the tail ends of the overhead power wires are further comprised; a photovoltaic power generation system generates power by means of solar energy, and conveys direct-current power onto the direct-current busbar; by being connected to the direct-current busbar, the direct-current ice melting system transmits the direct-current power on the direct-current busbar to the overhead power wires; the direct-current power passes through frozen overhead wires and flows into the ground by means of the ice-melting short-circuit disconnectors; and current flows through resistors on the overhead wires to generate heat, so that ice on the wires is slowly melted and falls off under the action of gravity, so as to achieve the purpose of melting ice. Under the condition that the overhead wires are not iced, the power generated by the photovoltaic power generation units is conveyed to a power grid by an inverter by means of the overhead line.

Description

System and method for melting ice on overhead lines using photovoltaic power generation

Technical field

The invention belongs to the technical field of new energy energy utilization, and specifically relates to a system and method for melting ice on overhead lines using photovoltaic power generation.

Background technique

Ice and snow disasters often pose a very big threat to the safety of power systems, and icing on overhead transmission lines is a common manifestation. Icing on overhead transmission lines is an important factor in dangerous events such as transmission line breaks and the collapse of transmission towers.

With the increasing awareness of the dangers of icing on transmission lines at home and abroad, various forms of ice melting methods have emerged. At present, there are more than 30 kinds of ice melting methods at home and abroad, which can be roughly divided into three categories: mechanical deicing method, natural deicing method and thermal ice melting method. It is agreed at home and abroad that the direct current method of ice melting in the wire thermal ice melting method is the most effective for the problem of icing on a large-scale transmission line.

DC current ice melting method: The principle of the DC ice melting technology is to use the ice-coating circuit as a load, apply a DC power supply, and use a lower voltage to provide a short-circuit current to heat the wire to melt the ice. Two solutions, generator power rectification and thyristor rectification using system power, can be used to convert high-voltage AC power into DC power. The short-circuit current heats the wire to make the wire heat to melt the ice on the transmission line, so as to prevent the line from being frozen due to ice. The inverted rod is broken.

Summary of the invention

The purpose of the present invention is to provide a system and method for melting ice on overhead lines using photovoltaic power generation. In the present invention, photovoltaic power generation components are used as power sources to connect the generated power to the DC bus bus, and the overhead wires are melted through the control of the DC ice melting system. , During the period when the overhead wires are not freezing, the photovoltaic modules generate electricity normally, and the electricity is input to the grid through the inverter.

In order to achieve the above objectives, the present invention adopts the following technical solutions to achieve:

A system for melting ice on overhead lines using photovoltaic power generation, including multiple photovoltaic power generation units, a DC bus connected to the multiple photovoltaic power generation units, a DC ice melting system connected to the DC bus bus, and a power overhead connected to the DC ice melting system Conductors are photovoltaic inverters that connect the DC bus and the power overhead wires when the power overhead wires are not frozen.

A system that uses photovoltaic power generation to melt ice on overhead lines. When the overhead wires are not frozen, the DC power generated by the photovoltaic power generation unit is transmitted to the DC bus bar, converted into AC power by the photovoltaic inverter, and transmitted through the uniced power overhead wires To the grid; when the power overhead wires are icing, the DC power generated by the photovoltaic power generation unit is transmitted to the DC bus, which is connected to the power overhead wires through the DC ice melting system, and the electrical energy is controlled by the DC ice melting system to make the power The current flowing on the overhead wire generates heat through the resistance, which melts the ice on the power overhead wire and falls under the action of gravity to achieve the purpose of melting the ice.

The DC ice melting system includes an ice melting side device configured at the beginning of the power overhead wire and a short connection side device configured at the end of the power overhead wire; the DC ice melting system ice melting side device includes a positive terminal and a negative terminal connected to the DC busbar , Phase selection switch A+ connected to the positive connector, phase selection switch B+, phase selection switch C+ and phase selection switch A- connected to the negative connection, phase selection switch B-, phase selection switch C-; phase selection The other end of switch A+ and phase selection switch A- is connected to DC melting bus A; the other end of phase selection switch B+ and phase selection switch B- is connected to DC melting bus B; the other end of phase selection switch C+ and phase selection switch C-The other end is connected to the DC ice melting bus C; one end of the ice melting switch A is connected to the DC ice melting bus A, and the other end is connected to the phase A of the electric overhead wire; one end of the ice melting switch B is connected to the DC ice melting bus B and the other end is connected to the electric overhead wire Phase B; One end of the ice melting switch C is connected to the DC ice melting bus C, and the other end is connected to the power overhead wire C phase; the DC ice melting system short-circuit side equipment includes the ice melting short circuit connecting the end of the overhead wire A phase and the power overhead wire B phase end Knife switch AB, and the ice-melting short-circuit knife switch BC that connects the end of the power overhead wire B-phase and the power overhead wire C-phase end;

And phase selection knife switch A+, phase selection knife switch B+, phase selection knife switch C+, phase selection knife switch A-, phase selection knife switch B-, phase selection knife switch C-, ice melting switch A, ice melting switch B, The ice-melting switch C, the ice-melting short-circuit switch AB, and the ice-melting short-circuit switch BC can all be electrically controlled by the DC ice melting controller or directly controlled manually.

According to the working method of the system using photovoltaic power generation to melt ice on overhead lines, two-phase serial ice melting or two-phase parallel and one-phase serial ice melting are selected according to the thickness of icing;

In the two-phase series mode, there are three ways to choose the power overhead conductor AB two-phase, the power overhead conductor BC two-phase, and the power overhead conductor AC two-phase; if the power overhead conductor AB is connected in series, the operation process is as follows: Disconnect the photovoltaic inverter Close the ice melting short-circuit switch AB, close the phase selection switch A+ to charge the DC melting bus A, close the phase selection switch B- to charge the DC melting bus B, and close the ice melting switch A and melting ice after charging is completed Switch B melts ice for power overhead conductors A phase and B phase; the operation process of the other two series modes is the same;

In the mode of two-phase parallel and one-phase series ice melting, select the power overhead conductor AB and the two-phase parallel connection and then the series power overhead conductor C phase, or the power overhead conductor BC two-phase parallel connection and then the series power overhead conductor A phase; if the power overhead conductor AB is two-phase parallel After connecting the power overhead conductor C phase in series, the operation process is as follows: first disconnect the photovoltaic inverter, then close the ice melting short-circuit switch AB and melting short-circuit switch BC at the same time, close the phase selection switch A+ to charge the DC melting bus A , Close the phase selection switch B+ to charge the DC melting bus B, close the phase selection knife C- to charge the DC melting bus C, and close the ice melting switch A, melting switch B, and melting switch C respectively after charging Overhead conductors A phase, B phase, and C phase melt ice; after the power overhead conductor BC two phases are connected in parallel, the operation process of the series power overhead conductor A phase is the same.

Compared with the existing technology, this solution uses photovoltaic power generation components as the power source for power generation. During normal operation, the photovoltaic components are normally connected to the grid through the inverter. In the case of severe icing on the transmission line, the photovoltaic components are connected to the power generation. The DC confluence bus bar melts ice through the control of the DC ice melting system. The present invention has the following advantages:

1. The present invention uses photovoltaic power generation as a power source for ice melting, and photovoltaic power generation is a renewable and clean energy source that does not pollute the environment.

2. The equipment of the existing DC ice melting system mainly includes transformers, rectifiers, AC filters, converter valves, etc. The investment is large, and the ice melting device has a short working time, and it is only used for ice melting, which will result in idle equipment resources. waste. However, the present invention uses photovoltaic power generation components as a DC power source, and the photovoltaic components generate electricity normally during normal operation to obtain electricity fee income, and when the line freezes, it is adjusted to the ice melting power source, which saves construction costs.

3. The photovoltaic power generation ice melting system converts solar energy into electric energy through photovoltaic modules, eliminating the need to purchase electricity from the grid, saving ice melting costs.

Description of the drawings

Figure 1 is a system block diagram of the present invention using photovoltaic power generation to melt ice on overhead lines.

Figure 2 is a schematic diagram of the DC ice melting system structure.

Detailed ways

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

As shown in Figure 1, a system for melting ice on overhead lines using photovoltaic power generation according to the present invention includes a plurality of photovoltaic power generation units 1, a DC bus 2 connected to the plurality of photovoltaic power generation units 1, and a DC bus connected to the DC bus 2 The ice melting system 3 is connected to the power overhead wire 5 of the DC ice melting system 3, and is connected to the DC busbar 2 and the photovoltaic inverter 4 of the power overhead wire 5 when the power overhead wire 5 is not frozen.

In a system that uses photovoltaic power generation to melt ice on overhead lines, when the overhead conductor 5 is not frozen, the DC power generated by the photovoltaic power generation unit 1 is transmitted to the DC bus bar 2, and is converted into AC power by the photovoltaic inverter 4, and passes through the uniced The power overhead wire 5 is transmitted to the power grid 6; when the power overhead wire 5 is icing, the DC power generated by the photovoltaic power generation unit 1 is transmitted to the DC busbar 2, which is connected to the power overhead wire 5 through the DC ice melting system 3. The electric energy is controlled by the DC ice melting system 4, so that the current flowing on the power overhead wire 5 generates heat through the resistance, so that the ice on the power overhead wire 5 melts and falls under the action of gravity to achieve the purpose of melting ice.

As shown in Figure 2, the DC ice melting system 3 includes ice-melting side equipment at the beginning of the power overhead conductor and a short-circuit side equipment at the end of the power overhead conductor; the DC ice melting system 3 includes the ice-melting side equipment and DC confluence The positive connector 31 and the negative connector 32 connected to the bus bar 2, the phase selection knife A+331 of the positive connector 31, the phase selection knife B+332, the phase selection knife C+333 and the phase selection knife connected to the negative connector 32 A-341, the phase selection switch B-342, the phase selection switch C-343; the other end of the phase selection switch A+331 and the phase selection switch A-341 are connected to the DC melting bus A 351; the phase selection switch B +332 and the other end of the phase selection switch B-342 are connected to the DC melting bus B 352; the other end of the phase selection switch C+333 and the phase selection switch C-343 are connected to the DC melting bus C 353; the ice melting switch A 361 One end is connected to the DC ice melting bus A 351, the other end is connected to the power overhead wire 5 phase A; one end of the ice melting switch B 362 is connected to the DC ice melting bus B 352, and the other end is connected to the power overhead wire 5 phase B; the ice melting switch C 363 is connected to one end DC ice melting bus C 353, the other end is connected to the power overhead wire 5 phase C; the DC ice melting system 3 short-circuit side equipment includes the connection of the overhead wire 5 A phase end and the power overhead wire 5 B phase end ice melting short circuit switch AB 37 , And the ice-melting short-circuit switch BC 38 that connects the end of the power overhead wire 5 phase B and the end of the power overhead wire 5 phase C;

And phase selection knife switch A+331, phase selection knife switch B+332, phase selection knife switch C+333, phase selection knife switch A-341, phase selection knife switch B-342, phase selection knife switch C-343, Rong Ice switch A 361, ice melting switch B 362, ice melting switch C 363, ice melting short-circuit knife AB 37, ice melting short-circuit knife BC 38, all of which can accept DC ice melting controller 39 for electric control or direct operation Manual control.

As shown in Fig. 1 and Fig. 2, the working method of the present invention uses photovoltaic power generation for overhead line ice melting system, according to the icing thickness, select two-phase serial ice melting or two-phase parallel one-phase serial ice melting;

In the two-phase series mode, there are three ways to select power overhead conductors 5 AB two-phase, power overhead conductors 5 BC two-phase, and power overhead conductors 5 AC two-phase; if the power overhead conductors 5 AB are connected in series, the operation process is as follows: Turn on the photovoltaic inverter 4, close the ice melting short-circuit switch AB 37, close the phase selection switch A+331 to charge the DC melting bus A 351, and close the phase selection switch B-342 to charge the DC melting bus B 352. After the charging is completed, close the ice melting switch A 361 and the ice melting switch B 362 to melt the ice of the power overhead wires 5 phase A and phase B; the other two series mode operation processes are the same;

In the two-phase parallel and one-phase series ice melting mode, select the power overhead conductor 5 AB two phases in parallel and connect the power overhead conductor in series 5 C phase, or the power overhead conductor 5 BC two phases in parallel and connect the power overhead conductor in series 5 A phase; if the power overhead conductor 5 After the two phases AB are connected in parallel, the power overhead conductor 5 is connected in series. The operation process is as follows: first disconnect the photovoltaic inverter 4, then close the ice-melting short-circuit switch AB 37 and the ice-melting short-circuit switch BC 38 at the same time, and close the phase selection knife Gate A+331 charges the DC ice melting bus A 351, closes the phase selection switch B+332 to charge the DC ice melting bus B 352, closes the phase selection switch C-343 to charge the DC ice melting bus C 353, after charging is completed Close the ice melting switch A 361, the ice melting switch B 362, and the ice melting switch C 363 respectively to melt the ice on the overhead conductors 5 A phase, B phase, and C phase; the power overhead conductor 5 BC two phases are connected in parallel and then the power overhead conductor 5 is connected in series. The operation process is the same.

Claims

A system for melting ice on overhead lines using photovoltaic power generation, which is characterized in that it includes a plurality of photovoltaic power generation units (1), a DC busbar (2) connected to the plurality of photovoltaic power generation units (1), and a DC busbar ( 2) DC ice melting system (3), connected to the power overhead wire (5) of the DC ice melting system (3), when the power overhead wire (5) is not frozen, connect the DC bus (2) and the power overhead wire (5) Photovoltaic inverter (4).
The system for melting ice on overhead lines using photovoltaic power generation according to claim 1, characterized in that: when the overhead wires (5) are not frozen, the DC power generated by the photovoltaic power generation unit (1) is transmitted to the DC bus (2) ), converted into alternating current by the photovoltaic inverter (4), and transmitted to the power grid (6) through the uniced power overhead wire (5); when the power overhead wire (5) is icing, the photovoltaic power generation unit (1) The generated DC power is transmitted to the DC bus (2), the DC bus (2) is connected to the power overhead conductor (5) through the DC ice melting system (3), and the electrical energy is controlled by the DC ice melting system (4) to make the power The current flowing on the overhead wire (5) generates heat through the resistance, so that the ice on the power overhead wire (5) is melted and falls under the action of gravity to achieve the purpose of melting ice.
The system for melting ice on overhead lines using photovoltaic power generation according to claim 1, characterized in that: the DC ice melting system (3) includes ice melting side equipment arranged at the beginning of the power overhead wire and a device configured at the end of the power overhead wire Short-circuit side equipment; DC ice melting system (3) The ice melting side equipment includes a positive connector (31) and a negative connector (32) connected to the DC busbar (2), and a phase selection switch A+ connected to the positive connector (31) (331), phase selection switch B+ (332), phase selection switch C+ (333) and phase selection switch A-(341) connected to the negative connector (32), phase selection switch B-(342), selection Phase switch C-(343); Phase selection switch A+ (331) and phase selection switch A-(341) The other end is connected to DC melting bus A (351); Phase selection switch B+ (332) and phase selection The other end of the switch B-(342) is connected to the DC melting bus B (352); the other end of the phase selection switch C+ (333) and the other end of the phase selection switch C-(343) are connected to the DC melting bus C (353); One end of ice switch A (361) is connected to DC ice melting bus A (351), and the other end is connected to power overhead wire (5) phase A; one end of ice switch B (362) is connected to DC ice melting bus B (352) and the other end is connected Power overhead wire (5) B phase; one end of ice melting switch C (363) is connected to DC ice melting bus C (353), and the other end is connected to power overhead wire (5) C phase; DC ice melting system (3) short-circuit side equipment Including the ice melting short-circuit switch AB (37) connecting the overhead wire (5) A phase end and the power overhead wire (5) B phase end, and connecting the power overhead wire (5) B phase end and the power overhead wire (5) C The melting short circuit knife BC(38) at the end of the phase;

And select the phase switch A+(331), select the phase switch B+(332), select the phase switch C+(333), select the phase switch A-(341), select the phase switch B-(342), select the phase switch Knife switch C-(343), ice melting switch A(361), ice melting switch B(362), ice melting switch C(363), ice melting short-circuit knife switch AB(37), ice melting short-circuit knife BC(38) ), can accept DC ice melting controller (39) for electric control or direct manual control.
The working method of the system for melting ice on overhead lines using photovoltaic power generation according to any one of claims 1 to 3, characterized in that: two-phase series ice melting or two-phase parallel and one-phase series ice melting are selected according to the thickness of icing;

In the two-phase series mode, there are three ways to select power overhead conductor (5) AB two-phase, power overhead conductor (5) BC two-phase, and power overhead conductor (5) AC two-phase; if power overhead conductor (5) AB two The operation process is as follows: disconnect the photovoltaic inverter (4), close the melting short circuit switch AB (37), close the phase selection switch A+ (331) to charge the DC melting bus A (351), close the selection Phase switch B-(342) charges the DC ice-melting bus B(352), after the charging is completed, close the ice-melting switch A(361) and the ice-melting switch B(362) to the power overhead conductor (5) A-phase, B-phase Melting ice

In two-phase parallel and one-phase series ice melting mode, select the power overhead conductor (5) AB two-phase parallel and connect the power overhead conductor in series (5) C phase, or the electric power overhead conductor (5) BC two-phase parallel and connect the power overhead conductor in series (5) ) Phase A; if the power overhead conductor (5) AB is connected in parallel and then the power overhead conductor (5) C phase is connected in series, the operation process is as follows: first disconnect the photovoltaic inverter (4), and then close the melting short-circuit switch AB at the same time (37) Short-circuit the ice-melting switch BC (38), close the phase selection switch A+ (331) to charge the DC melting bus A (351), and close the phase selection switch B+ (332) to the DC melting bus B( 352) Charge, close the phase selection switch C-(343) to charge the DC melting bus C (353), and close the ice melting switch A(361), melting ice switch B(362), and melting ice switch C after charging is completed. (363) Melt ice for overhead conductors (5) Phase A, Phase B and Phase C.