Disclosure of Invention
The invention aims to provide a structure of a traction substation with in-phase power supply, which can effectively solve the technical problem that traction power supply and compensation equipment share one transformer.
The invention also aims to provide a comprehensive compensation method for the in-phase power supply traction substation, which can effectively solve the technical problems of reducing the capacity of compensation equipment and simultaneously realizing real-time comprehensive compensation on reactive power and negative sequence generated by traction load of the electrified railway.
The purpose of the invention is realized by the following technical scheme: a structure of an in-phase power supply traction substation comprises a traction-compensation transformer TCT in a CSS of the in-phase power supply traction substation of an electrified railway, wherein the primary side of the traction-compensation transformer TCT is provided with two groups of windings which are marked as a first primary winding AB and a second primary winding BC, three terminals A, B, C are respectively led out and connected with a three-phase high-voltage bus HB, and the secondary side of the traction-compensation transformer TCT is provided with two groups of windings which are marked as a first secondary winding AB and a second secondary winding b' c; the relationship between the number of turns n of the first primary winding AB and the number of turns m of the second primary winding BC of the traction-compensating transformer TCT is: n is m; a first secondary winding ab of the traction-compensation transformer TCT is taken as a traction port, a tap d terminal is led out at the position of n ' of the number of turns of the winding by taking an a terminal of the first secondary winding ab as a reference, the tap d terminal is connected with a b ' terminal of a second secondary winding b ' c, and the number of turns of the second secondary winding b ' c is n '; wherein the values of n, m and n' are positive integers greater than 1; the first secondary winding ab and the second secondary winding b 'c respectively form an a terminal and a c terminal of a first compensation port, a c terminal and a b' terminal of a second compensation port and an a terminal and a d terminal of a third compensation port; the input end and the output end of a first high-power switch device SVG1 in the CCE are respectively connected with the terminal a and the terminal c of a first compensation port, the input end and the output end of a second high-power switch device SVG2 are respectively connected with the terminal c and the terminal b' of a second compensation port, and the input end and the output end of a third high-power switch device SVG3 are respectively connected with the terminal a and the terminal d of a third compensation port; the voltage transformer VT, the current transformer CT and the controller CD form a comprehensive compensation measurement and control system MCS, wherein the primary side of the voltage transformer VT is connected in parallel between the first secondary winding ab, the primary side of the current transformer CT is connected in series between the terminal a of the first secondary winding ab and the traction bus OCS, the signal input end of the controller CD is respectively connected with the measurement signal output ends of the voltage transformer VT and the current transformer CT, and the signal output end of the controller CD is connected with the control end of the comprehensive compensation equipment CCE.
If the power supply mode of the traction network is a direct power supply mode or a direct power supply mode with a return line, the terminal a of the first secondary winding ab of the traction-compensation transformer TCT is connected to the traction bus OCS, and the terminal b is connected with the steel rail R and the ground; and if the traction network power supply mode is an AT power supply mode, the terminal a of the first secondary winding ab of the traction-compensation transformer TCT is connected to the traction bus OCS, and the terminal b is connected with the negative feeder line F.
The other purpose of the invention is realized by the following technical scheme: a comprehensive compensation method for an in-phase power supply traction substation comprises the structure of the in-phase power supply traction substation, and comprises the following specific steps:
step one, taking the negative sequence allowance S of a three-phase high-voltage bus HBεAnd the power factor value mu is taken as a compensation target;
step two, calculating the voltage and current values measured by the voltage transformer VT and the current transformer CT through the controller CD of the comprehensive compensation measurement and control system MCS to obtain the traction load power S
LAnd power factor
And thus judging the negative sequence power of the traction load
With negative sequence allowance S
εThe relationship of (A), and the power factor
The relationship with the target power factor value μ is determined as follows:
(1) when in use
When, if
Then comprehensive compensation equipment CCE is put into to comprehensively compensate the negative sequence and the reactive power; if it is
The CCE only compensates the negative sequence;
(2) when in use
When, if
Then the CCE is put into the comprehensive compensation equipment to compensate the reactive power only; if it is
The CCE is in standby stateState.
The working time sequence of the power switch device when the CCE performs comprehensive compensation on the negative sequence and the reactive power is as follows: when in use
When the three-port compensation mode is adopted, a first high-power switching device SVG1, a second high-power switching device SVG2 and a third high-power switching device SVG3 are put into the three-port compensation mode; when in use
When, if
Only the third high-power switching device SVG3 is put into use, and the mode is simplified into a single-port compensation mode; if it is
The first high power switching device SVG1, the second high power switching device SVG2 and the third high power switching device SVG3 are all in standby state.
The three-port compensation mode has the following specific scheme:
(1) when in use
When, if
The reactive power Q emitted by the first high-power switching device SVG1, the second high-power switching device SVG2 and the third high-power switching device SVG3
1、Q
2And Q
3The sizes of (A) and (B) are respectively as follows:
wherein K is reactive compensation coefficient, the value range is more than 0 and less than or equal to 1, and the compensated power factor
The determination is made as to whether the user has selected,
when the traction load is in the traction condition, Q
1Is inductive/capacitive, Q
2Is capacitive/inductive, Q
3For compatibility, Q is the time when the traction load is in the regenerative braking regime
1Is capacitive/inductive, Q
2Is inductive/capacitive, Q
3Is perceptual;
(2) when in use
When, if
The reactive power Q emitted by the first high-power switching device SVG1, the second high-power switching device SVG2 and the third high-power switching device SVG3
1、Q
2And Q
3The sizes of (A) and (B) are respectively as follows:
when the traction load is in the traction condition, Q
1、Q
2And Q
3Respectively inductive, capacitive and capacitive, Q being the value of the traction load when it is in the regenerative braking regime
1、Q
2And Q
3Capacitive, inductive and inductive, respectively;
(3) when in use
When, if
Then the first high-power switching device SVG1 and the second high-power switching device SVG2 are in standby state at this time, and the reactive power Q emitted by the third high-power switching device SVG3
3The size of (A) is as follows:
wherein K is the reactive compensation coefficientK is more than 0 and less than or equal to 1, and the compensated power factor
The determination is made as to whether the user has selected,
when the traction load is in the traction condition, Q
3For compatibility, Q is the time when the traction load is in the regenerative braking regime
3Is perceptual;
(4) when in use
When, if
Then, the first high-power switching device SVG1, the second high-power switching device SVG2 and the third high-power switching device SVG3 are all in a standby state at this time, and the negative sequence and the reactive power generated by the traction load both meet the compensation target without additional compensation.
Compared with the prior art, the invention has the beneficial effects that:
the traction-compensation transformer is provided with the traction port and the compensation port simultaneously, so that the common-box manufacturing of the traction transformer and the compensation transformer is realized, the traction port and the compensation port can be shared by windings, the functional integration level is high, the equipment floor area and the transformer manufacturing difficulty are effectively reduced, meanwhile, the traction port is single-phase-change in nature, the capacity utilization rate is high, the installation capacity of equipment can be effectively reduced, in addition, the in-phase power supply is implemented by canceling the electric phase splitting at the outlet of a traction substation, the regenerative braking energy of a train can be utilized to a higher degree, the power consumption is reduced, and the energy utilization rate is improved;
the invention can realize the comprehensive compensation of the reactive power and the negative sequence of the three-phase power system, and effectively solves the problem of the quality of the electric energy which is mainly generated by the electrified railway to the three-phase power system and takes the negative sequence as the main point;
the comprehensive compensation equipment realizes comprehensive compensation by essentially controlling reactive power flow without changing the active power flow of a system and transmitting positive-sequence active power, and has the advantage of capacity-free electricity charge;
the invention is suitable for reactive and negative sequence comprehensive treatment of various AC-DC and AC-DC-AC electric locomotives, the working condition of the comprehensive compensation equipment is reversible, and when the traction load is in a regenerative braking working condition, the comprehensive compensation equipment can still feed electric energy meeting the standard to the power grid.
Detailed Description
In order to better understand the inventive idea of the present invention, the working principle of the present invention is briefly explained here: with negative sequence allowance S of three-phase high-voltage busεAnd the power factor value mu is a compensation target, and reactive power with corresponding properties is sent out by controlling the SVG connected to the secondary side compensation port of the traction-compensation transformer, so that reactive power and a negative sequence generated by the electrified railway are comprehensively compensated, and the compensated reactive power and negative sequence meet the requirement of the compensation target, wherein the SVG only changes reactive power flow of a system and does not change active power flow of the system. The invention is further described with reference to the following figures and detailed description.
Example one
As shown in fig. 1, an embodiment of the present invention provides a structure of a traction substation with in-phase power supply, including a traction-compensation transformer TCT, an integrated compensation device CCE, and an integrated compensation measurement and control system MCS, where a primary terminal of the traction-compensation transformer TCT is connected to a three-phase high-voltage bus HB, a secondary side of the traction-compensation transformer TCT has a first secondary winding ab as a traction port, and forms an a terminal and a c terminal of the first compensation port with a second secondary winding b 'c, a c terminal and a b' terminal of the second compensation port, and an a terminal and a d terminal of the third compensation port; the input end and the output end of a first high-power switching device SVG1 in the CCE are respectively connected with the terminal a and the terminal c of a first compensation port, the input end and the output end of a second high-power switching device SVG2 are respectively connected with the terminal c and the terminal b' of a second compensation port, and the input end and the output end of a third high-power switching device SVG3 are respectively connected with the terminal a and the terminal d of a third compensation port; the first secondary winding ab of the traction-compensation transformer TCT is connected with a traction network, wherein the primary side of a voltage transformer VT is connected in parallel between the first secondary windings ab, the primary side of a current transformer CT is connected in series between the terminal a of the first secondary winding ab and a traction bus OCS, if the power supply mode of the traction network is a direct power supply mode or a direct power supply mode with a backflow line, the first secondary winding ab of the traction-compensation transformer TCT is connected with the traction bus OCS through the terminal a, and the terminal b is connected with a steel rail R and the ground, wherein LC is a certain electric locomotive running on a line; if the power supply mode of the traction network is an AT power supply mode, as shown in fig. 2, the a terminal of the first secondary winding ab of the traction-compensation transformer TCT is connected to the traction bus OCS, and the b terminal is connected to the negative feeder F, where AT (1), AT (2).. AT (i) respectively indicate each AT station set in the AT power supply mode, and LC is a certain electric locomotive running on the line.
In this embodiment, as shown in fig. 1 and fig. 2, the comprehensive compensation measurement and control system MCS includes a voltage transformer VT, a current transformer CT and a controller CD, a signal input end of the controller CD is connected to a measurement signal output end of the voltage transformer VT and a measurement signal output end of the current transformer CT, respectively, and a signal output end of the controller CD is connected to control ends of a first high-power switching device SVG1, a second high-power switching device SVG2 and a third high-power switching device SVG3 of the comprehensive compensation device CCE.
Example two
As shown in fig. 3, in the traction-compensation transformer TCT according to the embodiment of the present invention, the primary and secondary sides of the traction-compensation transformer TCT have two sets of windings, where the primary winding is a first primary winding AB and a second primary winding BC, and the secondary winding is a first secondary winding AB and a second secondary winding b' c; a, B, C three terminals are led out from the primary side of the traction-compensation transformer TCT, a fifth terminal of a, d, b 'and c is led out from the secondary side of the traction-compensation transformer TCT, and the a terminal and the c terminal of the first compensation port, the c terminal and the b' terminal of the second compensation port, the a terminal and the d terminal of the third compensation port and the traction port, namely the first secondary winding ab are respectively formed by the terminals; in fig. 3, the dotted terminals of the transformer winding are shown.
In this embodiment, the relationship between the number of turns n of the first primary winding AB and the number of turns m of the second primary winding BC is as follows: n is m; the first secondary winding ab takes the terminal a as a reference, a tap terminal d is led out at the position n ' of the number of turns of the winding, the tap terminal d is connected with the terminal b ' of the second secondary winding b ' c, and the number of turns of the second secondary winding b ' c is n '; wherein the values of n, m and n' are positive integers greater than 1; the first secondary winding ab and the second secondary winding b' c are independent windings, and the voltage levels are independent.
EXAMPLE III
As shown in fig. 4, an embodiment of the present invention provides a schematic flow chart of an integrated compensation method for an in-phase power supply traction substation, and takes a situation when an integrated compensation device CCE is in a three-port compensation mode as an example, the integrated compensation method for the in-phase power supply traction substation includes the above-mentioned structure of the in-phase power supply traction substation, and includes the specific steps of:
step one, taking the negative sequence allowance S of a three-phase high-voltage bus HBεAnd the power factor value mu is taken as a compensation target;
step two, calculating the voltage and current values measured by the voltage transformer VT and the current transformer CT through the controller CD of the comprehensive compensation measurement and control system MCS to obtain the traction load power S
LAnd power factor
And thus judging the negative sequence power of the traction load
With negative sequence allowance S
εThe relationship of (A), and the power factor
A relation to a target power factor value μ;
(1) when in use
When the three-port compensation mode is adopted, a first high-power switching device SVG1, a second high-power switching device SVG2 and a third high-power switching device SVG3 are put into the three-port compensation mode;
(2) if it is
Then, the negative sequence and the reactive power are comprehensively compensated at the same time, and the reactive power Q emitted by the first high-power switching device SVG1, the second high-power switching device SVG2 and the third high-power switching device SVG3 at the moment
1、Q
2And Q
3The sizes of (A) and (B) are respectively as follows:
wherein K is reactive compensation coefficient, the value range is more than 0 and less than or equal to 1, and the compensated power factor
The determination is made as to whether the user has selected,
when the traction load is in the traction condition, Q
1Is inductive/capacitive, Q
2Is capacitive/inductive, Q
3For compatibility, Q is the time when the traction load is in the regenerative braking regime
1Is capacitive/inductive, Q
2Is inductive/capacitive, Q
3Is perceptual;
(3) if it is
Only the negative sequence is compensated without changing the system reactive power, and the reactive power Q emitted by the first high-power switching device SVG1, the second high-power switching device SVG2 and the third high-power switching device SVG3 at the moment
1、Q
2And Q
3The sizes of (A) and (B) are respectively as follows:
when the traction load is in the traction condition, Q
1、Q
2And Q
3Respectively inductive, capacitive and capacitive, Q being the value of the traction load when it is in the regenerative braking regime
1、Q
2And Q
3Capacitive, inductive and inductive, respectively;
(4) when in use
When, if
Only the third high-power switching device SVG3 is put into operation, the operation is further simplified into a single-port compensation mode, and at the moment, the first high-power switching device SVG1 and the second high-power switching device SVG2 are in a standby state;
(5) when in use
When, if
Then, the first high-power switching device SVG1, the second high-power switching device SVG2 and the third high-power switching device SVG3 are all in a standby state at this time, and the negative sequence and the reactive power generated by the traction load both meet the compensation target without additional compensation.