CN109050352B - Through type in-phase traction power supply system, traction substation and power supply control method thereof - Google Patents

Abstract

The invention relates to the technical field of power control, and particularly provides a through-type in-phase traction power supply system, a traction substation and a power supply control method thereof, aiming at solving the technical problem of how to reliably supply power to an electric locomotive. To this end, the present invention provides a traction substation comprising a plurality of power conversion devices. Specifically, the electric energy conversion device comprises single-phase transformers and electric energy converters, wherein a high-voltage winding of each single-phase transformer is connected with two different phase lines in a preset power grid respectively, a low-voltage winding of each single-phase transformer is connected with an input side port of the corresponding electric energy converter, and an output side port of each electric energy converter is connected with a preset contact net and a preset steel rail respectively. Based on above-mentioned structure, can guarantee when some electric energy conversion device break down, draw the electric substation and can also rely on other electric energy conversion device to continue to provide the constant supply voltage of voltage amplitude and unchangeable with the phase place to the contact net. The power supply system of the invention comprises the traction substation.

Description

Through-type in-phase traction power supply system, traction substation and power supply control method thereof

technical field

The invention relates to the technical field of electric power control, in particular to a through-type in-phase traction power supply system, a traction substation and a power supply control method thereof.

Background technique

The traction power supply system of electrified railway refers to the power supply system that supplies the traction power of electric locomotives, which is mainly composed of traction substation and catenary. The traction substation converts the three-phase AC power sent by the power plant through the high-voltage transmission line into the current and voltage suitable for the electric locomotive, and then sends it to the catenary, and then the catenary supplies power to the locomotive.

In order to meet the demand of single-phase power supply of railway system, electrified railway traction power supply system usually adopts split-phase power supply method to supply power to electric locomotives in different power supply sections (that is, different power supply sections use a certain phase of three-phase power grid for power supply) . However, there is an insulating area between the phases of the split-phase power supply. When the electric locomotive passes through the insulating area, the traction power supply system of the electrified railway will not be able to supply power to the electric locomotive normally. In this process, the traction force and speed of the electric locomotive will be lost and the negative sequence current will appear in the three-phase power grid, and the negative sequence current will become more serious with the increase of the power of the electric locomotive.

At present, the same-phase power supply system (such as the through-type same-phase power supply system) is mainly used to supply power to the electric locomotive to ensure that the amplitude and phase of the power supply voltage remain continuous and do not change abruptly during the operation of the electric locomotive (that is, when the same-phase power supply system is used for power supply, no split-phase power supply).

Referring to FIG. 5, FIG. 5 exemplarily shows the main structure of a traction substation suitable for a through-type in-phase power supply system. As shown in Figure 5, the traction substation includes a power frequency traction transformer and a three-phase-single-phase AC/AC converter. Among them, the power frequency traction transformer is a three-phase winding transformer. The high-voltage side windings of the three-phase winding transformer are respectively connected with the three phase lines of the power grid, and the low-voltage side windings are respectively connected with the three phase lines of the three-phase-single-phase AC/AC converter. AC input port connection. Although the through-type in-phase power supply system based on the above traction substation can ensure the same supply voltage between different traction substations, when the converter fails, it will not be able to supply power to the electric locomotive normally, so the reliability of power supply is poor.

SUMMARY OF THE INVENTION

In order to solve the above problems in the prior art, that is, to solve the technical problem of how to reliably supply power to an electric locomotive, the present invention provides a through-type in-phase traction power supply system, a traction substation and a power supply control method thereof.

In a first aspect, the traction substation in the present invention includes a plurality of electric energy conversion devices, the electric energy conversion devices include a single-phase transformer and an electric energy converter;

The high-voltage winding of each single-phase transformer is respectively connected with two different phase lines in the power grid, and the low-voltage winding of each single-phase transformer is connected to the input side port of the corresponding power converter;

The output side ports of each of the power converters are respectively connected with the catenary and the rail.

Further, a preferred technical scheme provided by the present invention is:

The electrical energy converter is an AC-AC converter.

Further, a preferred technical scheme provided by the present invention is:

The voltage transformation ratio of each of the single-phase transformers is the same;

The capacity of each of the power converters is the same.

Further, a preferred technical scheme provided by the present invention is:

The number of the power conversion devices is 2 or 3.

In the second aspect, the power supply control method of the traction substation in the present invention includes the following steps:

According to the preset load power demand, the input current closed-loop control is performed on the electric energy converter of each electric energy conversion device in the traction substation,

The output voltage closed-loop control is performed on the power converter of a certain power conversion device, and the output current closed-loop of the power converters of other power conversion devices is performed with the output current of the power converter of the certain power conversion device as the target value. tracking control.

Further, a preferred technical scheme provided by the present invention is:

When there are one or three power conversion devices in normal operation in the traction substation, the step of "carrying out the input current closed-loop control of the power converters of each power conversion device in the traction substation" includes:

Obtaining a given value of active current according to the active power output value of the power converter in the normally operating power conversion device and the grid line voltage corresponding to the normally operating power conversion device;

The input current closed-loop control is performed on the electric energy converter with the active current given value as the input current given value.

Further, a preferred technical scheme provided by the present invention is:

When there are two normally operating electric energy conversion devices in the traction substation, the step of "carrying out the input current closed-loop control of the electric energy converters of each electric energy conversion device in the traction substation" includes:

Obtaining a given value of active current according to the active power output value of the power converter in the normally operating power conversion device and the grid line voltage corresponding to the normally operating power conversion device;

According to the preset corresponding relationship between the active current and the reactive current, obtain the reactive current given value corresponding to the active current given value;

According to the given value of active current and given value of reactive current, the given value of input current is calculated to perform closed-loop control of input current on the power converter.

Further, a preferred technical scheme provided by the present invention is:

The phase of the active current given value is the same as the phase of the corresponding grid line voltage, and the amplitude of the active current given value is:

I _{Mref_p} = 2×P _M /U _M

Wherein, the I _{Mref_p} is the magnitude of the active current given value corresponding to the M-th power conversion device, the P _M is the active power output value of the power converter corresponding to the M-th power conversion device, and the U _M is the magnitude of the grid line voltage corresponding to the Mth power conversion device.

Further, a preferred technical scheme provided by the present invention is:

The phase of the given reactive current value is 90° different from the phase of the corresponding grid line voltage, and the magnitude of the given reactive current value is:

I _{Mref_q} =I _{Mref_p} ×tan(30°)

Wherein, the _{IMref_q} is the magnitude of the reactive current given value corresponding to the M th power conversion device, and the _{IMref_p} is the magnitude of the active current given value corresponding to the M th power conversion device.

Further, a preferred technical scheme provided by the present invention is:

The input current given value is:

i _Mref = i _{Mref_p} +i _{Mref_q}

Wherein, the i _Mref , i _{Mref_p} and i _{Mref_q} are respectively the input current given value, active current given value and reactive current given value corresponding to the Mth electric energy conversion device.

In a third aspect, the through-type in-phase traction power supply system of the present invention includes a plurality of traction substations described in the above technical solutions.

Compared with the closest prior art, the above technical solution at least has the following beneficial effects:

1. The traction substation in the present invention includes a plurality of electric energy conversion devices, and each electric energy conversion device includes a single-phase transformer and an electric energy converter. Specifically, the high-voltage windings of each single-phase transformer are respectively connected to two different phase lines in the power grid, and the low-voltage windings of each single-phase transformer are connected to the input side ports of the corresponding power converters. The output side ports of each power converter are respectively connected with the catenary and the rail. Based on the above structure, it can be ensured that when some power conversion devices fail, the traction substation can also rely on other power conversion devices to continuously provide continuous supply voltage with constant voltage amplitude and phase to the catenary, and the power supply reliability is high.

2. In the present invention, the transformation ratio of each single-phase transformer of the traction substation is the same. By controlling the output power of each electric energy conversion device to be the same, the capacity of each electric energy converter can be guaranteed to be the same.

3. The power supply control method of the traction substation in the present invention mainly includes the following steps: performing input current closed-loop control on the electric energy converter of each electric energy conversion device in the traction substation; The output voltage closed-loop control is performed, and the output current of the power converter of a certain power conversion device is taken as the target value to perform the output current closed-loop tracking control of the power converters of other power conversion devices. When there are two normally operating electric energy conversion devices in the traction substation Under the same conditions, the negative sequence current in the grid can be effectively eliminated.

Description of drawings

1 is a schematic diagram of the main structure of a through-type in-phase traction power supply system in an embodiment of the present invention;

2 is a schematic diagram of the main structure of a traction substation in an embodiment of the present invention;

3 is a schematic diagram of the main structure of two electric energy conversion devices contained in a traction substation in an embodiment of the present invention;

4 is a schematic diagram of the main structure of three electric energy conversion devices contained in a traction substation in an embodiment of the present invention.

Figure 5 is the main structure of a conventional traction substation.

Detailed ways

Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principle of the present invention, and are not intended to limit the protection scope of the present invention.

A through-type in-phase traction power supply system provided by the present invention will be described below with reference to the accompanying drawings.

Referring to FIG. 1 , FIG. 1 exemplarily shows the main structure of a through-type in-phase traction power supply system in this embodiment. As shown in FIG. 1 , the through-type in-phase traction power supply system in this embodiment may include a plurality of traction substations (traction substation 1 to traction substation n), and these traction substations are arranged in parallel in a preset Between the grid and the preset catenary/rail, the traction substation can convert the three-phase power of the grid into single-phase power to supply power to the catenary/rail.

Continuing to refer to FIG. 2 , FIG. 2 exemplarily shows the main structure of a traction substation that can be applied to the through-type in-phase traction power supply system shown in FIG. 1 in this embodiment. As shown in FIG. 2 , the traction substation in this embodiment mainly includes a plurality of power conversion devices (power conversion device 1 to power conversion device N, where N=2 or 3), and each power conversion device includes a single power conversion device. Phase transformers and power converters.

Specifically, in this embodiment, the high-voltage windings of each single-phase transformer are respectively connected to two different phase lines in the power grid (that is, the high-voltage windings of each single-phase transformer are respectively connected to one power grid line voltage), and each single-phase transformer The low-voltage winding is connected with the input side port of the corresponding power converter, and the output side port of each power converter is respectively connected with the catenary and the rail. Optionally, in this embodiment, the voltage transformation ratio of each single-phase transformer in the traction substation is the same, and the output power of each electric energy converter is the same, so that the capacity of each electric energy converter can be guaranteed to be the same.

In this embodiment, the electrical energy converter can convert the electrical energy output by the single-phase transformer into electrical energy that can be used by a load (eg, an electric locomotive). For example, when the power converter is an AC-AC converter, it can convert the power output by the single-phase transformer into AC power of a specific voltage level, and when the power converter is an AC-DC converter, it can convert the power output by the single-phase transformer. Converted to direct current at a specific voltage level.

In a preferred implementation of this embodiment, the traction substation shown in FIG. 2 may include two power conversion devices. The traction substation in this embodiment will be described below with reference to the accompanying drawings.

Referring to Fig. 3, Fig. 3 exemplarily shows the main structure of the traction substation in this embodiment. As shown in FIG. 3 , one power conversion device in the traction substation in this embodiment may include a single-phase transformer Ta and a power converter CPSC1 (for the sake of brevity, the power conversion device is described as power conversion device A), and another A power conversion device may include a single-phase transformer Tb and a power converter CPSC2 (for the sake of brevity, the power conversion device is described as a power conversion device B).

Specifically, in this embodiment, one end of the high-voltage winding of the single-phase transformer Ta in the power conversion device A (the T1 end shown in FIG. ₃ ) is connected to the first phase line of the power grid (the A-phase AC bus shown in FIG. 3 ) , the other end of the high-voltage winding of the single-phase transformer Ta (the T2 end shown in Figure ₃ ) is connected to the second phase line of the power grid (the B-phase AC bus shown in Figure 3), and the low-voltage winding of the single-phase transformer Ta is connected to the electrical energy The input side of the converter CPSC1 is connected.

The first electrode terminal on the input side of the power converter CPSC1 in the power conversion device A (X ₁ terminal shown in Figure 3) is connected to one end of the low-voltage winding of the single-phase transformer Ta (T ₃ terminal shown in Figure 3), and the electrical energy The second electrode terminal (X ₂ terminal shown in FIG. 3 ) on the input side of the converter CPSC1 is connected to the other terminal (T ₄ terminal shown in FIG. 3 ) of the low-voltage winding of the single-phase transformer Ta. The first electrode terminal on the output side of the power converter CPSC1 ( _X3 terminal shown in Figure 3) is connected to the catenary, and the second electrode terminal ( _X4 terminal shown in Figure 3) on the output side of the power converter CPSC1 is connected to the catenary. Rail connection.

One end of the high-voltage winding of the single-phase transformer Tb in the power conversion device B (the T5 end shown in Figure ₃ ) is connected to the second phase line of the power grid (the B-phase AC bus shown in Figure 3), and the high-voltage of the single-phase transformer Tb is connected. The other end of the winding (terminal _T6 shown in Figure 3) is connected to the third phase line of the power grid (the C-phase AC bus shown in Figure 3), and the low-voltage winding of the single-phase transformer Tb is connected to the input side of the power converter CPSC2 .

The first electrode terminal (X5 terminal shown in Figure ₃ ) of the input side of the power converter CPSC2 in the power conversion device B is connected to one end (T7 terminal shown in Figure ₃ ) of the low-voltage winding of the single-phase transformer Tb, and the power The second electrode terminal (X ₆ terminal shown in FIG. 3 ) on the input side of the converter CPSC2 is connected to the other terminal (T ₈ terminal shown in FIG. 3 ) of the low-voltage winding of the single-phase transformer Tb. The first electrode terminal on the output side of the power converter CPSC2 (X7 terminal shown in Figure 3) is connected to the catenary, and the second electrode terminal ( _X8 terminal shown in Figure ₃ ) on the output side of the power converter CPSC2 is connected to the catenary. Rail connection.

In another preferred implementation of this embodiment, the traction substation shown in FIG. 3 may further include three electric energy conversion devices. The traction substation in this embodiment will be described below with reference to the accompanying drawings.

Referring to FIG. 4, FIG. 4 exemplarily shows the main structure of the traction substation in this embodiment. As shown in FIG. 4 , the first power conversion device in the traction substation in this embodiment may include a single-phase transformer Ta and a power converter CPSC1 (for the sake of brevity, the power conversion device is described as power conversion device A) , the second power conversion device may include single-phase transformer Tb and power converter CPSC2 (for the sake of brevity, the power conversion device is described as power conversion device B), and the third power conversion device may include single-phase transformer Tc and power Converter CPSC3 (for the sake of brevity, the power conversion device is described as power conversion device C).

Specifically, the power conversion device A and the power conversion device B in this embodiment are respectively the same as the power conversion device A and the power conversion device B shown in FIG.

In this embodiment, one end of the high-voltage winding of the single-phase transformer Tc in the power conversion device C (the T9 end shown in FIG. ₄ ) is connected to the third phase line of the power grid (the C-phase AC bus shown in FIG. 4 ), The other end of the high-voltage winding of the single-phase transformer Tc (terminal T10 shown in Figure ₄ ) is connected to the first phase line of the power grid (the A-phase AC bus shown in Figure 4), and the low-voltage winding of the single-phase transformer Tc is converted with electric energy. connected to the input side of the controller CPSC3.

The first electrode terminal on the input side of the power converter CPSC3 in the power conversion device C (the X ₉ terminal shown in FIG. 4 ) is connected to one end of the low-voltage winding of the single-phase transformer Tc (the T ₁₁ terminal shown in FIG. 4 ), and the electrical energy The second electrode terminal ( _X10 terminal shown in FIG. 4 ) on the input side of the converter CPSC3 is connected to the other terminal ( _T12 terminal shown in FIG. 4 ) of the low-voltage winding of the single-phase transformer Tc. The first electrode terminal on the output side of the power converter CPSC3 (X11 terminal shown in Figure 4) is connected to the catenary, and the second electrode terminal ( _X12 terminal shown in Figure ₄ ) on the output side of the power converter CPSC3 is connected to the catenary. Rail connection.

Further, based on the above-mentioned embodiment of the traction substation, the present invention also provides a power supply control method for the traction substation described in the above-mentioned embodiment of the traction substation. Taking the traction substation shown in FIG. 4 as an example, the power supply control method of the traction substation provided by the present invention will be described below. Specifically, in this embodiment, the power supply control of the traction substation can be performed according to the following steps:

Step S101: According to the preset load power demand, perform input current closed-loop control on the electric energy converter of each electric energy conversion device in the traction substation.

In this embodiment, when there are one or three power conversion devices in normal operation in the traction substation (for example, the traction substation includes three power conversion devices and all three power conversion devices are in normal operation, or the traction substation includes three power conversion devices When three power conversion devices are included and two power conversion devices are faulty, or the traction substation includes two power conversion devices and one power conversion device is faulty), the input current given value can be obtained according to the following steps, so that the power The converter performs input current closed-loop control:

According to the active power output value of the power converter in the power conversion device and the grid line voltage corresponding to the power conversion device, obtain the active current given value, and use the active current given value as the input current given value to input the power converter. Current closed loop control. In this embodiment, the phase of the active current given value is the same as the phase of the corresponding grid line voltage, and the amplitude I _{Mref_p} of the active current given value is shown in the following formula (1):

I _{Mref_p} = 2×P _M /U _M (1)

The meaning of each parameter in formula (1) is:

PM is the active power output value of the power converter corresponding to the Mth power conversion device, and U _M is the magnitude of the grid line voltage corresponding to the _Mth power conversion device.

The following describes the specific operation process of obtaining the given current value by taking the electric energy conversion device A of the traction substation shown in FIG. 4 as an example.

For the power conversion device A, the input current given value i _Aref can be obtained according to the following steps: according to the grid line voltage U _AB input to the single-phase transformer Ta and the active power P ₁ of the power converter CPSC1, obtain the active current given value i _{Aref_p} . Specifically, the phase of the active current given value i _{Aref_p} is the same as the phase of the grid line voltage U _AB , and the current amplitude I _{Aref_p} of the active current given value i _{Aref_p} is shown in the following formula (2):

I _{Aref_p} = 2×P ₁ /U _AB (2)

Further, in this embodiment, when there are two normally operating power conversion devices in the traction substation (for example, the traction substation includes two power conversion devices and both power conversion devices are in normal operation, or the traction substation When three power conversion devices are included and one power conversion device fails), the input current given value can be obtained according to the following steps, so as to perform input current closed-loop control of the power converter:

First, obtain the active current given value according to the method shown in formula (1).

Then, according to the preset corresponding relationship between the active current and the reactive current, the given value of the reactive current corresponding to the given value of the active current is obtained. In this embodiment, the phase of the given value of reactive current is 90° different from the phase of the corresponding grid line voltage, and the amplitude I _{Mref_q} of the given value of reactive current is shown in the following formula (3):

I _{Mref_q} =I _{Mref_p} ×tan(30°) (3)

Finally, according to the given value of active current and given value of reactive current, the given value of input current corresponding to the input current closed-loop control of the power converter is calculated. In this embodiment, the input current given value i _Mref is shown in the following formula (4):

i _Mref = i _{Mref_p} + i _{Mref_q} (4)

The meaning of each parameter in formula (4) is:

i _{Mref_p} is a given value of active current corresponding to the M th power conversion device, and i _{Mref_q} is a given value of reactive current corresponding to the M th power conversion device.

Taking the traction substation shown in FIG. 4 as an example (assuming that the power converter CPSC3 corresponding to the power conversion device C is faulty), the above-mentioned specific operation process for obtaining a given current value will be described below.

For the electric energy conversion device A, the input current given value i _Aref can be obtained according to the following steps: First, the amplitude I _{Aref_p} of the active current given value i _{Aref_p} is obtained according to the method shown in formula (1). Then, the amplitude I _{Aref_q} of the given reactive current value i _{Aref_q} is obtained according to the method shown in the formula (3). Finally, the input current given value i _Aref is calculated according to the method shown in formula (4). Among them, the phase of the active current given value i _{Aref_p} is the same as the phase of the grid line voltage U _AB , and the phase of the reactive current given value i _{Aref_q} is 90° ahead of the phase of the grid line voltage U _AB .

For the power conversion device B, the input current given value i _Bref can be obtained according to the following steps: First, the amplitude I _{Bref_p} of the active current given value i _{Bref_p} is obtained according to the method shown in formula (1). Then, the amplitude I _{Bref_q} of the given reactive current value i _{Bref_q} is obtained according to the method shown in formula (3). Finally, the input current given value i _Bref is calculated according to the method shown in formula (4). Among them, the phase of the active current given value i _{Bref_p} is the same as the phase of the grid line voltage U _BC , and the phase of the reactive current given value i _{Bref_q} is 90° behind the phase of the grid line voltage U _BC .

In this embodiment, when the power converter CPSC3 fails, the power converter CPSC1 and the power converter CPSC2 can still operate normally, so that the traction substation can adopt a derating output method (the output power of the traction substation decreases To 2/3 of the original output power), the supply voltage with the same voltage amplitude and phase is continuously output to the catenary. At the same time, the input current given value of the power converter CPSC1 and the power converter CPSC2 includes reactive current, so that the negative sequence current on the grid side can be eliminated.

Step S102 : perform output voltage closed-loop control on the power converter of a certain power conversion device, and use the output current of the power converter of a certain power conversion device as a target value to perform output current closed-loop tracking on the power converters of other power conversion devices control.

The above-mentioned voltage/current control process will be described below by taking the traction substation shown in FIG. 4 as an example (assuming that the power conversion devices A to C are in normal operation).

For example, the output voltage of the power converter CPSC1 of the power conversion device A is closed-loop controlled, and the output current of the power converter CPSC1 is taken as the target value. Perform output current closed-loop tracking control.

For another example, the output voltage of the power converter CPSC2 of the power conversion device B is closed-loop controlled, and the output current of the power converter CPSC2 is taken as the target value. CPSC3 performs output current closed-loop tracking control.

For another example, the output voltage closed-loop control is performed on the power converter CPSC3 of the power conversion device C, and the output current of the power converter CPSC3 is taken as the target value. CPSC2 performs output current closed-loop tracking control.

When different transformers are connected to the same grid line voltage, there may be no current in a certain phase winding of the high-voltage winding of the transformer (that is, the current on the high-voltage side of the transformer is asymmetrical, which will cause the grid to generate negative sequence current), and it cannot pass through at this time. Adjust the input current of different converters to compensate the negative sequence current in the grid. In this embodiment, when the traction substation includes three power conversion devices (the traction substation shown in FIG. 4 ), the single-phase transformers of each power conversion device are respectively connected to different grid line voltages, which will not The problem of current asymmetry occurs, that is to say, it will not cause negative sequence current in the grid. When the traction substation includes two electric energy conversion devices connected to different line voltages (the traction substation shown in Figure 3), under the condition that the output power of each electric energy conversion device is guaranteed to be the same, the The power converter performs reactive current compensation, and only needs to ensure that each power converter is supplemented with reactive current of the same amplitude (that is, the reactive current given value is introduced in the input current closed-loop control), and the negative sequence current can be applied to the power grid. compensate.

It will be understood by those skilled in the art that the apparatus of the system in the embodiment can be adaptively changed and arranged in one or more systems different from the embodiment. The devices in the embodiments can be combined into one device, and furthermore they can be divided into sub-devices. All features disclosed in this specification (including accompanying claims, abstract and drawings) and any system or apparatus so disclosed may be employed in any combination, unless at least some of such features and/or procedures are mutually exclusive. All processes are combined. Each feature disclosed in this specification (including accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.

It should be noted that the above-described embodiments illustrate rather than limit the invention, and that alternative embodiments may be devised by those skilled in the art without departing from the scope of the appended claims. The words "comprising" and "comprising" do not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention can be implemented by means of hardware comprising several different elements and by means of a suitably programmed PC. The use of the words first, second, and third, etc. do not denote any order. These words can be interpreted as names.

Furthermore, those skilled in the art will appreciate that although some of the embodiments described herein include certain features, but not others, included in other embodiments, that combinations of features of different embodiments are intended to be within the scope of the invention within and form different embodiments. For example, in the claims of this invention, any of the claimed embodiments may be used in any combination.

So far, the technical solutions of the present invention have been described with reference to the preferred embodiments shown in the accompanying drawings, however, those skilled in the art can easily understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims (9)

1. The power supply control method of the traction substation is characterized in that the traction substation comprises a plurality of electric energy conversion devices, and each electric energy conversion device comprises a single-phase transformer and an electric energy converter; the high-voltage winding of each single-phase transformer is respectively connected with two different phase lines in a power grid, and the low-voltage winding of each single-phase transformer is connected with the input side port of the corresponding electric energy converter; the output side port of each electric energy converter is respectively connected with a contact net and a steel rail; the power supply control method comprises the following steps:

performing input current closed-loop control on the electric energy converter of each electric energy conversion device in the traction substation according to a preset load power requirement,

and carrying out output voltage closed-loop control on the electric energy converter of a certain electric energy conversion device, and carrying out output current closed-loop tracking control on the electric energy converters of other electric energy conversion devices by taking the output current of the electric energy converter of the certain electric energy conversion device as a target value.

2. The power supply control method of the traction substation according to claim 1, wherein when one or three normally operating power conversion devices are present in the traction substation, the step of performing input current closed-loop control on the power converter of each power conversion device in the traction substation comprises:

obtaining an active current given value according to an active power output value of an electric energy converter in the normally-operated electric energy conversion device and a power grid line voltage corresponding to the normally-operated electric energy conversion device;

and performing input current closed-loop control on the electric energy converter by taking the active current given value as an input current given value.

3. The power supply control method for the traction substation according to claim 1, wherein when there are two normally operating power conversion devices in the traction substation, the step of performing input current closed-loop control on the power converter of each power conversion device in the traction substation includes:

obtaining an active current given value according to an active power output value of an electric energy converter in the normally-operated electric energy conversion device and a power grid line voltage corresponding to the normally-operated electric energy conversion device;

obtaining a reactive current given value corresponding to the active current given value according to a preset corresponding relation between the active current and the reactive current;

and calculating an input current given value according to the active current given value and the reactive current given value so as to perform input current closed-loop control on the electric energy converter.

4. The power supply control method of the traction substation according to claim 2, wherein the phase of the active current given value is the same as the phase of the corresponding grid line voltage, and the amplitude of the active current given value is:

I _{Mref_p}=2×P _M/U _M

wherein, theI _{Mref_p}Is the amplitude of the active current set value corresponding to the Mth electric energy conversion deviceP _MIs an active power output value of a power converter corresponding to the Mth power conversion deviceU _MIs the amplitude of the grid line voltage corresponding to the mth power conversion device.

5. The power supply control method of the traction substation according to claim 3, wherein the phase of the given reactive current value is different from the phase of the corresponding grid line voltage by 90 °, and the amplitude of the given reactive current value is:

I _{Mref_q}=I _{Mref_p}×tan(30°)

wherein, theI _{Mref_q}Is the amplitude of the given reactive current value corresponding to the Mth electric energy conversion deviceI _{Mref_p}Is the amplitude of the active current set value corresponding to the Mth electric energy conversion device.

6. The power supply control method of the traction substation according to claim 3, wherein the input current set value is:

i _Mref=i _{Mref_p}+i _{Mref_q}

wherein, thei _Mref、i _{Mref_p} Andi _{Mref_q} the input current given value, the active current given value and the reactive current given value which correspond to the Mth electric energy conversion device are respectively set.

7. The power supply control method for a traction substation according to claim 1, wherein the power converter is an ac-ac converter.

8. The power supply control method for a traction substation according to claim 7, wherein the power supply control method further comprises the step of controlling the power supply to the traction substation,

the voltage ratio of each single-phase transformer is the same;

the capacity of each of the power converters is the same.

9. The power supply control method for a traction substation according to claim 1, 7 or 8, wherein the number of said power conversion devices is 2 or 3.

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