An electrified railway same-phase power supply comprehensive compensation device and comprehensive compensation method thereof

Abstract

The present invention discloses an electric railway co-phase power supply integrated compensation device and a compensation method thereof, and relates to the technical field of electric railway co-phase power supply. Topological structure one, the compensation windings ab and dc of the traction compensation transformer whose primary side is connected to the three phases of the three-phase high-voltage bus HB; the reactive compensation unit SVG1 is connected to the ac port of the compensation winding, and the reactive compensation unit SVG2 is connected to the ad port of the compensation winding; topological structure two, the compensation windings ab and dc of the traction compensation transformer whose primary side is connected to the three phases of the three-phase high-voltage bus HB; the reactive compensation unit SVG1 is connected to the ac port of the compensation winding, the reactive compensation unit SVG2 is connected to the ad port of the compensation winding, and the reactive compensation unit SVG3 is connected to the ab port of the compensation winding; the input end of the controller CD in the measurement and control system MCS is respectively connected to the measurement signal output ends of the voltage transformer VT and the current transformer CT.

Description

Technical Field

[0001] The invention relates to the technical field of AC electrified railway traction power supply. Background Art

[0002] The rapid development of China's high-speed railways has further demonstrated the superiority of China's existing AC electrified railway power supply system with industrial frequency single-phase. Single-phase industrial frequency power supply requires the installation of electrical phase separation at the phase separation and partition. In order to reduce the impact of traction load on the imbalance of the power system, a scheme of rotating phase sequence and phase separation and partition power supply is usually adopted. Practice and theory have shown that electrical phase separation is the weakest link in the traction power supply system. When a train passes through an electrical phase separation, operational overvoltage and train phase loss may occur. In order to improve transportation quality, ensure operational reliability, reduce train phase loss, and improve the utilization rate of train regenerative braking energy, the number of electrical phase separations should be minimized.

[0003] Existing over-phase technology is mainly divided into ground automatic over-phase technology and vehicle-mounted automatic over-phase technology. However, multiple overvoltage phenomena have occurred in actual operation, which has brought serious impacts and hidden dangers to the safe operation of electrified railways, and power supply breakpoints still exist. The fundamental measure to eliminate the adverse effects of phase separation is to reduce or eliminate phase separation. Professors of Southwest Jiaotong University first proposed the concept of co-phase power supply, and led the scientific research team to conduct a large number of fruitful research, forming a complete theory and engineering technology of co-phase power supply system. The use of co-phase power supply technology can cancel the phase separation at the outlet of the substation, and the use of new bilateral power supply technology can cancel the phase separation at the partition, realize the phase-free through power supply of the entire line, and eliminate the adverse effects of phase separation. Among them, bilateral power supply has been widely used by the Soviet Union. Bilateral power supply has problems such as through power (balanced current), protection coordination, and electricity billing. These problems can be solved technically at a lower cost, but the difficulty lies in whether the power department accepts it.

[0004] Compared with the combined co-phase power supply technology that uses active active power flow to achieve comprehensive compensation of negative sequence and reactive power, the present invention achieves comprehensive compensation of negative sequence and reactive power based on active reactive power flow, does not change the existing active power flow of the system, achieves co-phase power supply, and at the same time takes into account compensation for harmonic current problems that may be caused by the traction load at the three-phase high-voltage bus. Summary of the invention

[0005] The purpose of the present invention is to provide a comprehensive compensation device for the same-phase power supply of an electrified railway, which effectively solves the influence of the AC electrified railway on the three-phase voltage imbalance at the public connection point without causing new power quality problems.

[0006] Another object of the present invention is to provide a comprehensive compensation method for the same-phase power supply of an electrified railway, which effectively solves the impact of AC electrified railway on the unbalanced three-phase voltage at the common connection point without causing new power quality problems.

[0007] The objective of the present invention is achieved through the following technical solutions: an electrified railway co-phase power supply integrated compensation device, comprising a three-phase high-voltage busbar HB connected to a power grid substation and a traction-compensation transformer TT connected to the three-phase high-voltage busbar HB on the primary side, a negative-sequence compensation device NCD and a measurement and control system MCS to form a co-phase power supply traction substation CSS; the secondary winding a1b1 port of the traction-compensation transformer TT is connected in series with a current transformer CT and then connected to the contact network OCS, and the other side port is connected in parallel with a voltage transformer VT and then grounded; the negative-sequence compensation device NCD includes two topological structures including the traction-compensation transformer TT and its secondary compensation winding and reactive compensation unit; one of the topological structures: when described as a two-port compensation mode, the two terminals of the reactive compensation unit SVG1 are respectively connected to the a terminal of the compensation winding ab of the secondary side of the traction-compensation transformer TT and the c terminal of the compensation winding cd, and the two terminals of the reactive compensation unit SVG2 are respectively connected to the a terminal of the compensation winding ab of the secondary side of the traction-compensation transformer TT and the d terminal of the compensation winding cd; topological structure Second: When the three-port compensation mode is described, the two terminals of the reactive compensation unit SVG1 are respectively connected to the a terminal of the compensation winding ab and the c terminal of the compensation winding cd of the secondary side of the traction-compensation transformer TT, the two terminals of the reactive compensation unit SVG2 are respectively connected to the a terminal of the compensation winding ab and the d terminal of the compensation winding cd of the secondary side of the traction-compensation transformer TT, and the two terminals of the reactive compensation unit SVG3 are respectively connected to the a terminal and the b terminal of the compensation winding ab of the secondary side of the traction-compensation transformer TT; the measurement and control system MCS includes a voltage transformer VT, a current transformer CT and a controller CD, and the input end of the controller CD is respectively connected to the measurement signal output end of the voltage transformer VT and the current transformer CT; if it is a two-port compensation mode, the output end of the controller CD is respectively connected to the control end of the reactive compensation unit SVG1 and the reactive compensation unit SVG2, and if it is a three-port compensation mode, the output end of the controller CD is respectively connected to the control end of the reactive compensation unit SVG1, the reactive compensation unit SVG2 and the reactive compensation unit SVG3.

[0008] If the traction network power supply mode is direct supply mode or direct supply mode with return line, one terminal of the traction winding a1b1 on the secondary side of the traction-compensating transformer TT is grounded, and the other terminal is connected to the contact network OCS. If the traction network power supply mode is AT power supply mode, one terminal of the traction winding a1b1 on the secondary side of the traction-compensating transformer TT is connected to the contact network OCS, and the other terminal is connected to the negative feeder.

[0009] The secondary winding a1b1 and the compensating winding ab of the traction-compensating transformer TT are two independent windings or a composite winding a1b is formed by the a1 tap of the secondary winding a1b1 of the traction-compensating transformer TT and the b tap of the compensating winding ab, and the terminal b1 and the terminal a of the composite winding a1b are led out from the same tap.

[0010] The relationship between the number of turns m of the primary winding AB of the traction-compensation transformer TT and the number of turns n of the primary winding CD is: The relationship between the number of turns m′ of the compensation winding ab on the secondary side of the traction-compensation transformer TT and the number of turns n′ of the compensation winding cd is: n′=2m′.

[0011] Another object of the present invention is to achieve the following technical solution: a method for comprehensive compensation of co-phase power supply for electrified railways, comprising the following specific steps:

[0012] (1) The load process of the traction substation is determined through computer simulation technology. According to the load process of the traction substation, the topology of the negative sequence compensation device (NCD) is selected and the form of the final topology is determined.

[0013] (2) The negative sequence allowable value S at the common connection point corresponding to the three-phase high-voltage bus HB ε As its negative sequence power allowable value;

[0014] (3) The controller CD calculates the load S through the voltage and current measured by the voltage transformer VT and the current transformer CT. L , determine the load S L Negative sequence power The negative sequence allowable power S of the three-phase high-voltage bus ε Relationship: If At this time, there is no need to compensate for the negative sequence; if At this time, negative sequence needs to be managed.

[0015] (4) If The negative sequence compensation device NCD is put into operation, and the controller CD controls the corresponding reactive power compensation unit to generate reactive power to achieve negative sequence control.

[0016] When the two-port compensation mode is adopted, the comprehensive compensation method only compensates the negative sequence current generated by the fundamental active current component of the load; by controlling the reactive power Q generated by the reactive power compensation unit SVG1 1 And the reactive power Q generated by the reactive power compensation unit SVG2 2 The size and type of can realize the comprehensive compensation of negative sequence and reactive power; if the power factor at the three-phase high-voltage bus remains unchanged after compensation, the sizes of reactive power compensation unit SVG1 and reactive power compensation unit SVG2 are: When the feeder load is in traction mode, Q1 and Q 2 are inductive and capacitive respectively; when the feeder load is in regenerative condition, Q 1 and Q 2 They are capacitive and inductive respectively.

[0017] When the three-port compensation mode is adopted, the comprehensive compensation method controls the reactive power Q generated by the reactive power compensation unit SVG1. 1 And the reactive power Q generated by the reactive power compensation unit SVG2 2 And the reactive power Q generated by the reactive power compensation unit SVG3 3 The size and type of the reactive power compensation unit SVG1, reactive power compensation unit SVG2 and reactive power compensation unit SVG3 are respectively: When the feeder load is in traction mode, Q 1 , Q 2 and Q 3 are inductive, capacitive, and capacitive respectively; when the feeder load is in regenerative condition, Q 1 , Q 2 and Q 3 They are capacitive, perceptual, and sensible respectively.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. This technical solution is applicable to negative sequence control in various power factor locomotive situations;

[0020] Second, this technical solution can achieve comprehensive compensation of negative sequence and reactive power;

[0021] 3. The traction transformer and the compensation transformer can be manufactured in the same box, saving floor space;

[0022] Fourth, the present invention has simple results, reliable technology, superior performance and is easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the structure of the two-port compensation mode of the present invention.

[0024] Figure 2 It is a structural schematic diagram of the relationship between the two-port compensation mode measurement and control system of the present invention and the reactive power compensation unit and traction load signal acquisition.

[0025] Figure 3 It is a schematic diagram of the structure of the three-port compensation mode of the present invention.

[0026] Figure 4It is a structural schematic diagram of the relationship between the three-port compensation mode measurement and control system of the present invention and the reactive power compensation unit and traction load signal acquisition.

[0027] Figure 5 It is a flow chart of the comprehensive compensation method of the present invention.

[0028] Figure 6 The present invention is a traction-compensation transformer winding connection schematic diagram.

[0029] Figure 7 This is another wiring diagram of the traction-compensation transformer winding of the present invention. DETAILED DESCRIPTION

[0030] In order to better understand the creative idea of ​​the present invention, the working principle of the present invention is explained here: the three-phase high-voltage bus is used as the negative sequence standard assessment point, and the SVG reactive compensation unit connected to the compensation transformer emits reactive power to compensate for the negative sequence current (power) generated by the feeder load, and the national standard requirements are met after compensation, wherein the reactive compensation unit does not change the original active power flow of the system. The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0031] Embodiment 1

[0032] like Figure 1 As shown, an embodiment of the present invention provides one of the topological structures: a schematic diagram of an electrified railway co-phase power supply integrated compensation device in a two-port compensation mode, including a three-phase high-voltage busbar HB connected to a power grid substation and a traction-compensation transformer TT, a negative sequence compensation device NCD and a measurement and control system MCS connected to the three-phase high-voltage busbar HB on the primary side to form a co-phase power supply traction substation CSS; the secondary winding a1b1 port of the traction-compensation transformer TT is connected in series with a current transformer CT and then connected to the contact network OCS, and the other side port is connected in parallel with a voltage transformer VT and then grounded; the two-port compensation mode includes compensation windings ab and dc of the traction-compensation transformer connected to the A, B, and C phases of the three-phase high-voltage busbar HB on the primary side, a reactive compensation unit SVG1 and a reactive compensation unit SVG2, the reactive compensation unit SVG1 is connected to the ac port of the compensation winding of the traction-compensation transformer, and the reactive compensation unit SVG2 is connected to the ad port of the compensation winding of the traction-compensation transformer; Figure 1 In the figure, ·, △, and * represent the same-named ends of the winding of the traction-compensation transformer TT.

[0033] like Figure 2 As shown, the measurement and control system MCS includes a voltage transformer VT, a current transformer CT and a controller CD, the input end of the controller CD is respectively connected to the voltage transformer VT, the current transformer CT and the measurement signal output end of the controller CD, and the output end of the controller CD is respectively connected to the control end of the reactive compensation unit SVG1 and the reactive compensation unit SVG2.

[0034] Embodiment 2

[0035] like Figure 3 As shown, the embodiment of the present invention provides a second topological structure: a schematic diagram of an electrified railway co-phase power supply integrated compensation device in a three-port compensation mode, including a three-phase high-voltage busbar HB connected to a power grid substation and a traction-compensation transformer TT connected to the three-phase high-voltage busbar HB on the primary side, a negative sequence compensation device NCD and a measurement and control system MCS to form a co-phase power supply traction substation CSS; the secondary winding a1b1 port of the traction-compensation transformer TT is connected in series with a current transformer CT and then connected to the contact network OCS, and the other side port is connected in parallel with a voltage transformer VT and then grounded; the three-port compensation mode includes compensation windings ab and dc of the traction-compensation transformer connected to the A, B, and C phases of the three-phase high-voltage busbar HB on the primary side, a reactive compensation unit SVG1, a reactive compensation unit SVG2 and a reactive compensation unit SVG3, the reactive compensation unit SVG1 is connected to the ac port of the compensation winding of the traction-compensation transformer, the reactive compensation unit SVG2 is connected to the ad port of the compensation winding of the traction-compensation transformer, and the reactive compensation unit SVG3 is connected to the ab port of the compensation winding of the traction-compensation transformer; Figure 3 In the figure, ·, △, and * represent the same-named ends of the winding of the traction-compensation transformer TT.

[0036] like Figure 4 As shown, in an embodiment of the present invention, the measurement and control system MCS is composed of a voltage transformer PT, a current transformer CT and a controller CD; the input end of the controller CD is respectively connected to the measuring ends of the voltage transformer PT and the current transformer CT, and the output end of the controller CD is respectively connected to the control ends of the reactive compensation unit SVG1, the reactive compensation unit SVG2 and the reactive compensation unit SVG3.

[0037] Embodiment 3

[0038] like Figure 5 As shown, an embodiment of the present invention provides a flow chart of a method for comprehensive compensation of co-phase power supply for electrified railways. This embodiment takes a comprehensive compensation method in a two-port compensation mode as an example. The specific steps of a method for comprehensive compensation of co-phase power supply for electrified railways are as follows:

[0039] (1) The load process of the traction substation is determined through computer simulation technology. According to the load process of the traction substation, the topology of the negative sequence compensation device (NCD) is selected and the form of the final topology is determined.

[0040] (2) The negative sequence allowable value S at the common connection point corresponding to the three-phase high-voltage bus HB ε As its negative sequence power allowable value;

[0041] (3) The controller CD calculates the load S through the voltage and current measured by the voltage transformer VT and the current transformer CT. L , determine the load S L Negative sequence power The negative sequence allowable power S of the three-phase high-voltage bus ε Relationship: If At this time, there is no need to compensate for the negative sequence; if At this time, negative sequence needs to be managed.

[0042] (4) If The negative sequence compensation device NCD is put into operation, and the controller CD controls the corresponding reactive power compensation unit to emit reactive power to achieve negative sequence control. If the power factor at the three-phase high-voltage bus remains unchanged after compensation, the sizes of the reactive power compensation unit SVG1 and the reactive power compensation unit SVG2 are: When the feeder load is in traction mode, Q 1 and Q 2 are inductive and capacitive respectively; when the feeder load is in regenerative condition, Q 1 and Q 2 They are capacitive and inductive respectively.

[0043] Embodiment 4

[0044] like Figure 6 As shown, an embodiment of the present invention provides a schematic diagram of the connection of a traction-compensation transformer winding, wherein the secondary winding a1b1 and the secondary winding ab of the traction-compensation transformer TT are two independent windings.

[0045] like Figure 7 As shown, an embodiment of the present invention provides a schematic diagram of the connection of a traction-compensation transformer winding, wherein the a1 tap of the secondary winding a1b1 of the traction-compensation transformer TT and the b tap of the compensation winding ab constitute a composite winding a1b, and the terminal b1 and the terminal a of the composite winding a1b are led out from the same tap.

Claims

1. A method for comprehensive compensation of co-phase power supply for electrified railways, using a comprehensive compensation device for co-phase power supply for electrified railways for compensation, wherein: The comprehensive compensation device includes a three-phase high-voltage busbar HB connected to the power grid substation and a traction-compensation transformer TT connected to the three-phase high-voltage busbar HB on the primary side, a negative-sequence compensation device NCD and a measurement and control system MCS to form a co-phase power supply traction substation CSS; the secondary winding a1b1 port of the traction-compensation transformer TT is connected in series with a current transformer CT and then connected to the contact network OCS, and the other side port is connected in parallel with a voltage transformer VT and then grounded; it is characterized in that: the negative-sequence compensation device NCD includes two topological structures including the traction-compensation transformer TT and its secondary compensation winding and reactive compensation unit; one of the topological structures: when described as a two-port compensation mode, the two terminals of the reactive compensation unit SVG1 are respectively connected to the a terminal of the compensation winding ab of the secondary side of the traction-compensation transformer TT and the c terminal of the compensation winding cd, and the two terminals of the reactive compensation unit SVG2 are respectively connected to the a terminal of the compensation winding ab of the secondary side of the traction-compensation transformer TT and the d terminal of the compensation winding cd; the second topological structure: described as a three-port compensation mode In the two-port compensation mode, the two terminals of the reactive compensation unit SVG1 are respectively connected to the a terminal of the compensation winding ab and the c terminal of the compensation winding cd of the secondary side of the traction-compensation transformer TT, the two terminals of the reactive compensation unit SVG2 are respectively connected to the a terminal of the compensation winding ab and the d terminal of the compensation winding cd of the secondary side of the traction-compensation transformer TT, and the two terminals of the reactive compensation unit SVG3 are respectively connected to the a terminal and the b terminal of the compensation winding ab of the secondary side of the traction-compensation transformer TT; the measurement and control system MCS includes a voltage transformer VT, a current transformer CT and a controller CD, and the input end of the controller CD is respectively connected to the measurement signal output end of the voltage transformer VT and the current transformer CT; if it is a two-port compensation mode, the output end of the controller CD is respectively connected to the control end of the reactive compensation unit SVG1 and the reactive compensation unit SVG2, and if it is a three-port compensation mode, the output end of the controller CD is respectively connected to the control end of the reactive compensation unit SVG1, the reactive compensation unit SVG2 and the reactive compensation unit SVG3; The specific steps of the comprehensive compensation method are: (1) Determine the load process of the traction substation through computer simulation technology, select the topology of the negative sequence compensation device (NCD) according to the load process of the traction substation, and determine the form of the final topology; (2) The negative sequence allowable value S at the common connection point corresponding to the three-phase high-voltage bus HB ε As its negative sequence power allowable value; (3) The controller CD calculates the load S through the voltage and current measured by the voltage transformer VT and the current transformer CT. L , determine the load S L Negative sequence power The negative sequence allowable power S of the three-phase high-voltage bus ε Relationship: If At this time, there is no need to compensate for the negative sequence; if At this time, negative sequence needs to be governed; (4) If The negative sequence compensation device NCD is put into operation, and the controller CD controls the corresponding reactive power compensation unit to generate reactive power to achieve negative sequence control; When the three-port compensation mode is adopted, the comprehensive compensation method realizes the comprehensive compensation of negative sequence and reactive power by controlling the size and type of reactive power Q1 emitted by reactive power compensation unit SVG1, reactive power Q2 emitted by reactive power compensation unit SVG2, and reactive power Q3 emitted by reactive power compensation unit SVG3; in one case, if the power factor at the three-phase high-voltage bus HB is not changed after compensation, the sizes of reactive power compensation unit SVG1, reactive power compensation unit SVG2, and reactive power compensation unit SVG3 are respectively: When the feeder load is in traction condition, Q1, Q2 and Q3 are inductive, capacitive and capacitive respectively; when the feeder load is in regeneration condition, Q1, Q2 and Q3 are capacitive, inductive and inductive respectively.

2. The method for comprehensive compensation of co-phase power supply for electrified railway according to claim 1, characterized in that: If the traction network power supply mode is direct supply mode or direct supply mode with return line, one terminal of the traction winding a1b1 on the secondary side of the traction-compensating transformer TT is grounded, and the other terminal is connected to the contact network OCS. If the traction network power supply mode is AT power supply mode, one terminal of the traction winding a1b1 on the secondary side of the traction-compensating transformer TT is connected to the contact network OCS, and the other terminal is connected to the negative feeder.

3. The method for comprehensive compensation of co-phase power supply for electrified railway according to claim 1, characterized in that: The secondary winding a1b1 and the compensating winding ab of the traction-compensating transformer TT are two independent windings or a composite winding a1b is formed by the tap al of the secondary winding a1b1 of the traction-compensating transformer TT and the tap b of the compensating winding ab, and the terminal b1 and the terminal a of the composite winding a1b are led out from the same tap.

4. The method for comprehensive compensation of co-phase power supply for electrified railway according to claim 1, characterized in that: The relationship between the number of turns m of the winding AB of the primary side of the traction-compensation transformer TT and the number of turns n of the winding D of the primary side is: The relationship between the number of turns m′ of the compensation winding ab on the secondary side of the traction-compensation transformer TT and the number of turns n′ of the compensation winding cd is: n′=2m′.

5. A method for comprehensive compensation of co-phase power supply for electrified railway according to any one of claims 1 to 4, characterized in that: When the two-port compensation mode is adopted, the comprehensive compensation method only compensates the negative sequence current generated by the fundamental active current component of the load; by controlling the size and type of the reactive power Q1 emitted by the reactive compensation unit SVG1 and the reactive power Q2 emitted by the reactive compensation unit SVG2, the comprehensive compensation of negative sequence and reactive power can be achieved; if the power factor at the three-phase high-voltage bus remains unchanged after compensation, the sizes of the reactive compensation units SVG1 and SVG2 are respectively: When the feeder load is in traction condition, Q1 and Q2 are inductive and capacitive respectively; when the feeder load is in regenerative condition, Q1 and Q2 are capacitive and inductive respectively.

Images