CN111130046A - Ice melting loop of overhead contact system of electrified railway and control method thereof - Google Patents

Abstract

The invention provides an ice melting loop of an overhead contact system of an electrified railway and a control method thereof, and relates to the technical field of power supply of the electrified railway. The head end of a traction bus TB provided with a voltage transformer VT is connected in parallel between a switch K1 and a switch K2 in a primary side circuit of a matching transformer MT; a tap g of the MT secondary side of the matching transformer is connected with a terminal a of the SVG 1; a terminal b of the static var generator SVG1 is connected with the steel rail T; a power supply arm head end C1 is connected in series with a switch K3 and then connected in parallel between a g tap of the MT secondary side of the matching transformer and a connection line of an a terminal of the SVG1, a current transformer CT is arranged between the connection lines of the power supply arm head end C1 and the power supply arm K3, and a power supply arm head end C1 is connected in series with a switch K4 and a traction bus TB; the terminal C of the static var generator SVG2 is connected in series with the switch K5 and connected in parallel with the terminal C2 of the power supply arm, and the terminal d of the static var generator SVG2 is connected with the steel rail T.

Description

Ice melting loop of overhead contact system of electrified railway and control method thereof

Technical Field

The invention relates to the technical field of electrified railway power supply.

Background

China has wide breadth, electrified railways are all around the country, and due to the fact that climate conditions of the regions are complex, contact net icing conditions exist in both south and north.

The hazards of contact net icing include: (1) when the ice coating thickness of the contact net exceeds the ice coating limit, the problems of wire breakage, breakage and deformation of the supporting column and the supporting device and the like can occur. (2) The ice coating and ice shedding on the same wire are not uniform, so that the wire is waved, and accidents such as wire breakage or component failure can be caused in serious cases; (3) when the contact net is iced, part of conductive particles are iced on the surface of the insulator string, the conductivity of the surface of the insulator string is obviously improved when the ice layer is melted, and flashover accidents are easy to occur, so that the line is frequently tripped, and the insulator string is carbonized and damaged; (4) the contact line is coated with ice, so that the sliding plate and the contact line can not be directly contacted through the ice layer, and the contact plate and the contact line are burnt by electric arc. Therefore, the research on the catenary ice melting method has positive significance on the stable operation of the traction power supply system.

At present, there are many researches on anti-ice melting devices based on static Var generators (svg). The method takes the power transmission line as a load, outputs larger reactive current through reactive compensation equipment, and achieves the aim of ice prevention or ice melting by using Joule heat. Theoretically, the SVG has high regulation speed and wide operation range, can meet the ice-proof and ice-melting requirements under different meteorological conditions, but has larger ice-melting current and larger ice-melting device capacity, is limited to the voltage and current levels of the current full-control power electronic devices, is difficult to realize large-capacity compensation, has larger equipment investment and is not economical enough.

Disclosure of Invention

The invention aims to provide an ice melting loop of an electrified railway and a control method thereof, which can effectively solve the technical problem that the capacity of an ice melting device is reduced.

The purpose of the invention is realized by the following technical scheme: the utility model provides an electronic railway connecting net ice-melt return circuit, includes traction transformer TT, traction bus TB and static var generator, the concrete structure of connecting net ice-melt return circuit is:

the primary side of the traction transformer TT is connected with A, B, C of a three-phase power grid, one end of the secondary side is connected with a steel rail or grounded, and the other end of the secondary side is connected with a switch K1 in series, a switch K2 and an e tap of the primary side of the matching transformer MT in series; the head end of a traction bus TB provided with a voltage transformer VT is connected in parallel between a switch K1 and a switch K2 in a primary side circuit of a matching transformer MT; a tap g of the MT secondary side of the matching transformer is connected with a terminal a of the SVG 1; a terminal b of the static var generator SVG1 is connected with the steel rail T; the f tap of the primary side of the matching transformer MT is grounded with the h tap of the secondary side; a power supply arm head end C1 is connected in series with a switch K3 and then connected in parallel between a g tap of the MT secondary side of the matching transformer and a connection line of an a terminal of a static var generator SVG1, a current transformer CT is arranged between the power supply arm head end C1 and the connection line of the switch K3, and a power supply arm head end C1 is connected in series with a switch K4 and a traction bus TB; a terminal C of the static var generator SVG2 is connected in series with a switch K5 and then is connected in parallel with the terminal C2 of the power supply arm, and a terminal d of the static var generator SVG2 is connected with a steel rail T; the measuring end of the current transformer CT, the measuring end of the voltage transformer VT, the measuring end of the meteorological sensor MS and the measuring end of the ice thickness measuring device IM are all connected with the input interface of the measuring unit MU, the output interface of the measuring unit MU is connected with the input interface of the ice melting control unit CU, and the output interface of the ice melting control unit CU is respectively connected with the input port of the power control unit PU and the input port of the switch control unit SU; the output port of the switch control unit SU is respectively connected with the control ends of the switch K1, the switch K2, the switch K3, the switch K4 and the switch K5; the output port of the power control unit PU is respectively connected with the control ends of the static var generator SVG1 and the static var generator SVG 2;

control method for ice melting loop of overhead contact system of electrified railway

First, Ice melting Loop preparation

Monitoring meteorological conditions along the line, the icing thickness of a contact network, the head end current of a power supply arm and the head end voltage in real time through five sensing devices of a measuring unit MU; when the ice melting control unit CU judges that the overhead line system meets the ice melting condition, the switch control unit SU controls the switch K4 and the switch K1 to be opened in sequence, and the overhead line system is powered off; then controlling a switch K2 to be closed, accessing a matching transformer MT and a static var generator SVG1, closing a switch K3, connecting a head end C1 of a power supply arm to a secondary side of the matching transformer MT, closing a switch K5, and accessing a static var generator SVG 2; finally, a switch K1 is controlled to be switched on, and the ice melting loop is put into use;

second, melting ice

The power control unit PU controls the static var generator SVG2 to generate reactive current meeting ice melting requirements, and controls the static var generator SVG1 to generate reactive current which is equal to the static var generator SVG2 in size and opposite in property, so that the reactive current circulates in an ice melting loop of a contact network, and ice is melted by Joule heat;

thirdly, exiting the ice-melting state

When the ice melting control unit CU judges that the contact network does not meet the ice melting condition, the power control unit PU controls the SVG1 and the SVG2 to stop working, and the switch control unit SU controls the switch K1 to open; then controlling the switch K5, the switch K3 and the switch K2 to be opened in sequence, and stopping the ice melting device from running; and finally, the switch K1 and the switch K4 are controlled to be switched on in sequence, and the contact net recovers power supply.

The working principle of the invention is as follows: when the overhead line system meets the set ice melting condition, the head end C1 of the power supply arm is disconnected from the traction bus TB to the MT secondary side of the matching transformer, and the voltage of the overhead line system is reduced from 27.5kV to the voltage of the low-voltage side of the matching transformer. The static var generator SVG2 generates reactive current meeting ice melting requirements, and the static var generator SVG1 generates reactive current which is equal to the static var generator SVG2 in size and opposite in nature, so that the reactive current circulates in the built ice melting loop of the traction network, and ice is melted by Joule heat.

Compared with the prior art, the invention has the beneficial effects that:

the contact net is in a low-voltage state during ice melting, on one hand, the tail end SVG can be directly connected with the tail end of the power supply arm, and no matching transformer is needed, so that the number of matching transformers needed by the ice melting device is reduced; on the other hand, under the condition of a certain ice melting current, the capacity of the ice melting device can be effectively reduced along with the reduction of the voltage of the traction network, so that the technical difficulty and the cost investment of ice melting are reduced, and the ice melting efficiency and the practicability are improved.

Drawings

FIG. 1 is a schematic structural diagram of an embodiment of the present invention

FIG. 2 is a control flow diagram of the present invention

Detailed Description

The invention is further described with reference to the following figures and detailed description. The specific process for building the contact net ice melting loop comprises the following steps:

the primary side of the traction transformer TT is connected with A, B, C of a three-phase power grid, one end of the secondary side is connected with a steel rail or grounded, and the other end of the secondary side is connected with a switch K1 in series, a switch K2 and an e tap of the primary side of the matching transformer MT in series; the head end of a traction bus TB provided with a voltage transformer VT is connected in parallel between a switch K1 and a switch K2 in a primary side circuit of a matching transformer MT; a tap g of the MT secondary side of the matching transformer is connected with a terminal a of the SVG 1; a terminal b of the static var generator SVG1 is connected with the steel rail T; the f tap of the primary side of the matching transformer MT is grounded with the h tap of the secondary side; a power supply arm head end C1 is connected in series with a switch K3 and then connected in parallel between a g tap of the MT secondary side of the matching transformer and a connection line of an a terminal of a static var generator SVG1, a current transformer CT is arranged between the power supply arm head end C1 and the connection line of the switch K3, and a power supply arm head end C1 is connected in series with a switch K4 and a traction bus TB; the static var generator SVG2 can be arranged at the tail end of a power supply arm according to the ice melting requirement to melt ice coating on the power supply arm between a traction substation and a sub-area, or can be arranged at an adjacent traction substation to melt ice coating on a contact net between two traction substations, when the ice coating on the power supply arm is melted, a C terminal of the static var generator SVG2 is connected with a switch K5 in series and then connected with a C2 at the tail end of the power supply arm in parallel, and a d terminal of the static var generator SVG2 is connected with a steel rail T; the measuring end of the current transformer CT, the measuring end of the voltage transformer VT, the measuring end of the meteorological sensor MS and the measuring end of the ice thickness measuring device IM are all connected with the input interface of the measuring unit MU, the output interface of the measuring unit MU is connected with the input interface of the ice melting control unit CU, and the output interface of the ice melting control unit CU is respectively connected with the input port of the power control unit PU and the input port of the switch control unit SU; the output port of the switch control unit SU is respectively connected with the control ends of the switch K1, the switch K2, the switch K3, the switch K4 and the switch K5; the output port of the power control unit PU is respectively connected with the control ends of the static var generator SVG1 and the static var generator SVG 2;

2. control method for ice melting loop of overhead contact system of electrified railway

First, Ice melting Loop preparation

Monitoring meteorological conditions along the line, the icing thickness of a contact network, the head end current of a power supply arm and the head end voltage in real time through five sensing devices of a measuring unit MU; when the ice melting control unit CU judges that the overhead line system meets the ice melting condition, the switch control unit SU controls the switch K4 and the switch K1 to be opened in sequence, and the overhead line system is powered off; then controlling a switch K2 to be closed, accessing a matching transformer MT and a static var generator SVG1, closing a switch K3, connecting a head end C1 of a power supply arm to a secondary side of the matching transformer MT, closing a switch K5, and accessing a static var generator SVG 2; finally, a switch K1 is controlled to be switched on, and the ice melting loop is put into use;

second, melting ice

The power control unit PU controls the static var generator SVG2 to generate reactive current meeting ice melting requirements, and controls the static var generator SVG1 to generate reactive current which is equal to the static var generator SVG2 in size and opposite in property, so that the reactive current circulates in an ice melting loop of a contact network, and ice is melted by Joule heat;

thirdly, exiting the ice-melting state

When the ice melting control unit CU judges that the contact network does not meet the ice melting condition, the power control unit PU controls the SVG1 and the SVG2 to stop working, and the switch control unit SU controls the switch K1 to open; then controlling the switch K5, the switch K3 and the switch K2 to be opened in sequence, and stopping the ice melting device from running; and finally, the switch K1 and the switch K4 are controlled to be switched on in sequence, and the contact net recovers power supply.

Claims (2)

1. The utility model provides an electronic railway connecting net ice-melt return circuit, includes traction transformer TT, traction bus TB and static var generator, the concrete structure of connecting net ice-melt return circuit is:

the primary side of the traction transformer TT is connected with A, B, C of a three-phase power grid, one end of the secondary side is connected with a steel rail or grounded, and the other end of the secondary side is connected with a switch K1 in series, a switch K2 and an e tap of the primary side of the matching transformer MT in series; the head end of a traction bus TB provided with a voltage transformer VT is connected in parallel between a switch K1 and a switch K2 in a primary side circuit of a matching transformer MT; a tap g of the MT secondary side of the matching transformer is connected with a terminal a of the SVG 1; a terminal b of the static var generator SVG1 is connected with the steel rail T; the f tap of the primary side of the matching transformer MT is grounded with the h tap of the secondary side; a power supply arm head end C1 is connected in series with a switch K3 and then connected in parallel between a g tap of the MT secondary side of the matching transformer and a connection line of an a terminal of a static var generator SVG1, a current transformer CT is arranged between the power supply arm head end C1 and the connection line of the switch K3, and a power supply arm head end C1 is connected in series with a switch K4 and a traction bus TB; a terminal C of the static var generator SVG2 is connected in series with a switch K5 and then is connected in parallel with the terminal C2 of the power supply arm, and a terminal d of the static var generator SVG2 is connected with a steel rail T; the measuring end of the current transformer CT, the measuring end of the voltage transformer VT, the measuring end of the meteorological sensor MS and the measuring end of the ice thickness measuring device IM are all connected with the input interface of the measuring unit MU, the output interface of the measuring unit MU is connected with the input interface of the ice melting control unit CU, and the output interface of the ice melting control unit CU is respectively connected with the input port of the power control unit PU and the input port of the switch control unit SU; the output port of the switch control unit SU is respectively connected with the control ends of the switch K1, the switch K2, the switch K3, the switch K4 and the switch K5; the output port of the power control unit PU is connected with the control ends of the static var generator SVG1 and the static var generator SVG2 respectively.

2. Control method for ice melting loop of overhead contact system of electrified railway

First, Ice melting Loop preparation

Monitoring meteorological conditions along the line, the icing thickness of a contact network, the head end current of a power supply arm and the head end voltage in real time through five sensing devices of a measuring unit MU; when the ice melting control unit CU judges that the overhead line system meets the ice melting condition, the switch control unit SU controls the switch K4 and the switch K1 to be opened in sequence, and the overhead line system is powered off; then controlling a switch K2 to be closed, accessing a matching transformer MT and a static var generator SVG1, closing a switch K3, connecting a head end C1 of a power supply arm to a secondary side of the matching transformer MT, closing a switch K5, and accessing a static var generator SVG 2; finally, a switch K1 is controlled to be switched on, and the ice melting loop is put into use;

second, melting ice

The power control unit PU controls the static var generator SVG2 to generate reactive current meeting ice melting requirements, and controls the static var generator SVG1 to generate reactive current which is equal to the static var generator SVG2 in size and opposite in property, so that the reactive current circulates in an ice melting loop of a contact network, and ice is melted by Joule heat;

thirdly, exiting the ice-melting state

When the ice melting control unit CU judges that the contact network does not meet the ice melting condition, the power control unit PU controls the SVG1 and the SVG2 to stop working, and the switch control unit SU controls the switch K1 to open; then controlling the switch K5, the switch K3 and the switch K2 to be opened in sequence, and stopping the ice melting device from running; and finally, the switch K1 and the switch K4 are controlled to be switched on in sequence, and the contact net recovers power supply.

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