Subway power supply system operation method based on sharing

Abstract

The invention relates to the technical field of metro power supply system operation modes, in particular to a sharing-based metro power supply system operation method, and provides a reactive compensation scheme of a metro power supply system under the background of resource sharing of a main substation. The minimum reactive power compensation amount before and after resource sharing of the main substation under the condition that the PCC full-day power factor reaches the standard is calculated, and a reactive power compensation scheme comprising various reactive power compensation devices is provided. According to the scheme, on the basis that the minimum reactive power compensation amount before and after main substation resource sharing meets the compensation requirement, the installation capacity of the SVG and the electric reactor or the capacitor is determined with the minimum SVG capacity as the target, and the investment cost of a power supply system is reduced.

Description

Technical Field

[0001] This invention relates to the technical field of subway power supply system operation mode, and in particular to a subway power supply system operation method based on sharing. Background Technology

[0002] Under the current trend, subways have long since moved away from single-line construction and become networked construction, resulting in a large number of high-voltage power supply points. These power supply points also cause a great waste of the power supply resources of the urban power grid. Breaking the situation of independent construction of power supply systems for single subway lines and realizing resource sharing of main substations has become a research trend. However, the subway power supply system is complex and needs to be adjusted according to the configuration of electrical equipment. This requires professional technicians to increase their research efforts on resource sharing technology for subway power supply systems.

[0003] When the main substations of the urban subway power supply system share resources, the investment cost of the power supply system can be saved. In this context, in order to make the power factor of the PCC (point of common coupling) meet the standard, it is necessary to study the reactive power compensation scheme for the main substation resource sharing at different stages.

[0004] Taking the power supply system of subway lines as an example, based on the train schedule and power supply system structure, the minimum reactive power compensation amount before and after resource sharing of the main substation is calculated under the condition that the power factor of the PCC meets the standard throughout the day. A reactive power compensation setting scheme considering resource sharing of the main substation is proposed. Based on meeting the compensation requirements with the minimum reactive power compensation amount before and after resource sharing of the main substation, and with the minimum capacity of SVG (Static Var Generator) as the goal, determining the installation capacity of SVG and reactors or capacitors is a more realistic solution. Therefore, considering and planning the subway power supply system of Shanghai from the perspective of the network is not only conducive to improving the power supply reliability of the subway system and reducing investment costs, but also conducive to the rational use and development planning of urban power grid resources.

[0005] Currently, the power supply methods of subway power supply systems are mainly divided into distributed power supply and centralized power supply. The power factor of distributed and centralized power supply methods is analyzed, and it is pointed out that the centralized power supply method requires reactive power compensation on the 35kV side of the main substation. The installed capacity of SVG (Static Var Generator) is obtained, the power factor of the centralized compensation method is analyzed, its reactive power compensation scheme is studied, and the calibrated principle of reactive power compensation device is proposed. However, the existing methods do not consider the reactive power compensation scheme of the subway power supply system under the background of resource sharing of the main substation. Summary of the Invention

[0006] This invention aims to solve the technical problem of the lack of reliable reactive power compensation methods in the operation of shared subway power supply systems in the prior art, and provides an operation method for shared subway power supply systems.

[0007] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0008] The operation method of a shared subway power supply system includes:

[0009] Step S1: Perform power analysis on the preset time periods of the main substation and its power supply zone in the subway power supply system.

[0010] Step S2: Set the main transformer to have j power supply zones, and divide the whole day into i time periods according to the characteristics of subway operating time;

[0011] Where i=1 represents peak operating hours; i=2 represents off-peak operating hours; and i=3 represents non-operating hours.

[0012] The j-th power supply zone contains M traction substations with hybrid traction and step-down substations and N step-down substations.

[0013] Where m is the mth traction substation in the jth power supply zone that is connected to the 35kV busbar of the main substation;

[0014] n is the nth step-down substation in the jth power supply zone that is connected to the 35kV busbar of the main substation;

[0015] Step S3: Based on information such as the number of subway train departures, basic vehicle attributes, power supply system structure diagram, and power load design plan, calculate the active power Pv and reactive power Qv of the m-th traction substation connected to the 35kV busbar of the main substation in the j-th power supply zone of the i-th time period, and the active power Pw and reactive power Qw of the n-th step-down substation connected to the 35kV busbar of the main substation in the j-th power supply zone of the i-th time period through the AC / DC power flow of the subway power supply system.

[0016] Let Ppcc(i) and Qpcc(i) represent the active power and reactive power at PCC in the i-th time period.

[0017] Specifically, Ppcc(i) and Qpcc(i) are represented as Equation (1) and Equation (2), respectively;

[0018] Formula (1):

[0019] Formula (2):

[0020] In formulas (1) and (2):

[0021] Qe(i) represents the reactive power compensated by the reactive power compensation device in the i-th time period;

[0022] Qe(i) represents positive inductive reactive power;

[0023] Q(i) represents negative capacitive reactive power.

[0024] Specifically, the daily active energy WpPcc and reactive energy WoPcc at PCC can be expressed as formula (3):

[0025]

[0026] In formula (3):

[0027] T represents the operating duration of the i-th time period.

[0028] Specifically, the power factor λpcc at the PCC can be expressed by formula (4):

[0029]

[0030] Specifically, when the number of subway trains is small, the capacitive reactive power of the cables in the power supply system is large, and the power factor at the PCC is lower than the preset threshold, the subway power supply system starts the reactive power compensation device to carry out the reactive power compensation process in order to make the PCC power factor meet the standard.

[0031] The reactive power compensation process is as follows:

[0032] When the main substation resources are shared, the power supply system structure will change before and after sharing. Therefore, it is necessary to comprehensively consider the power distribution of the power supply system before and after sharing the main substation resources, and combine different types of reactive power compensation equipment to achieve the power factor at the PCC while minimizing the investment cost of the power supply system.

[0033] Specifically, using a linear programming method, the absolute value of the reactive power Qe compensated by the reactive power compensation device before resource sharing in the main substation, |Qe|, is used as the compensation amount of the reactive power compensation device SVG plus reactor or capacitor. The constraint condition is that the absolute value of the power factor at PCC is not less than 0.9.

[0034] Specifically, the linear programming model before resource sharing in the main substation can be expressed as formula (5):

[0035]

[0036] In the resource sharing model, if the main substation needs to supply power to other lines, the active power WpPcc and reactive power Wopcc at PCC will change after resource sharing.

[0037] Based on formulas (1) to (5), the reactive power Qe that the reactive power compensation device needs to compensate after the main substation resource sharing can be obtained.

[0038] Specifically, reactive power compensation is achieved by using SVG plus reactors or capacitors;

[0039] When Q and Qe are positive and negative the same, the smaller value between IQe| and |Qe,1| is selected as the installation capacity of the reactor or capacitor, and the difference between |Qe| and |Qe,| is used as the installation capacity of the SVG.

[0040] When Q and Qe are not positive or negative, the smaller value between |Q.| and lQe,1| is selected as the installed capacity of SVG, and the difference between IQe| and IQe,1| is used as the installed capacity of reactor or capacitor.

[0041] Specifically, the reactive power compensation scheme is expressed by formulas (6) and (7):

[0042]

[0043] In formula (7):

[0044] Sx represents the installed capacity of the reactor or capacitor;

[0045] Ssg represents the installation capacity of the SVG.

[0046] The present invention has the following beneficial effects:

[0047] Firstly, this scheme can calculate the minimum reactive power compensation amount before and after resource sharing of the main substation under the condition that the PCC's daily power factor meets the standard, based on the train schedule and power supply system structure, and proposes a reactive power compensation scheme that includes multiple reactive power compensation devices.

[0048] Secondly, the proposed scheme is based on meeting the compensation requirements with the minimum reactive power compensation amount before and after the main substation resource sharing, and aims to minimize the SVG capacity to determine the installation capacity of SVG and reactors or capacitors. Attached Figure Description

[0049] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0050] Figure 1 This is a schematic diagram of the method process of the present invention;

[0051] Figure 2 This is an example of a compensation scheme under the shared nature of the present invention;

[0052] Figure 3 The chart shows the active and reactive power at different times before and after the main substation resource sharing according to the present invention.

[0053] Figure 4This is the partition data for the reactive power compensation configuration scheme of the present invention. Detailed Implementation

[0054] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention. It should be noted that, for ease of description, in this application, "left side" is referred to as "first end", "right side" as "second end", "upper side" as "first end", and "lower side" as "second end" in the current view. The purpose of such description is to clearly express the technical solution and should not be construed as an improper limitation of the technical solution of this application.

[0055] In one specific embodiment, please refer to Figure 1-4 As shown, the operation method of the shared subway power supply system includes:

[0056] Step S1: Perform power analysis on the preset time periods of the main substation and its power supply zone in the subway power supply system.

[0057] Step S2: Set the main transformer to have j power supply zones, and divide the whole day into i time periods according to the characteristics of subway operating time;

[0058] Where i=1 represents peak operating hours; i=2 represents off-peak operating hours; and i=3 represents non-operating hours.

[0059] The j-th power supply zone contains M traction substations with hybrid traction and step-down substations and N step-down substations.

[0060] Where m is the mth traction substation in the jth power supply zone that is connected to the 35kV busbar of the main substation;

[0061] n is the nth step-down substation in the jth power supply zone that is connected to the 35kV busbar of the main substation;

[0062] Step S3: Based on information such as the number of subway train departures, basic vehicle attributes, power supply system structure diagram, and power load design plan, calculate the active power Pv and reactive power Qv of the m-th traction substation connected to the 35kV busbar of the main substation in the j-th power supply zone of the i-th time period, and the active power Pw and reactive power Qw of the n-th step-down substation connected to the 35kV busbar of the main substation in the j-th power supply zone of the i-th time period through the AC / DC power flow of the subway power supply system.

[0063] Let Ppcc(i) and Qpcc(i) represent the active power and reactive power at PCC in the i-th time period.

[0064] Furthermore, Ppcc(i) and Qpcc(i) are represented as Equation (1) and Equation (2), respectively;

[0065] Formula (1):

[0066] Formula (2):

[0067] In formulas (1) and (2):

[0068] Qe(i) represents the reactive power compensated by the reactive power compensation device in the i-th time period;

[0069] Qe(i) represents positive inductive reactive power;

[0070] Q(i) represents negative capacitive reactive power.

[0071] The advantages of the above scheme are as follows: This scheme can calculate the minimum reactive power compensation amount before and after the main substation resource sharing under the condition that the PCC power factor meets the standard throughout the day, based on the train schedule and the power supply system structure, and proposes a reactive power compensation scheme that includes multiple reactive power compensation devices; the proposed scheme is based on meeting the compensation requirements with the minimum reactive power compensation amount before and after the main substation resource sharing, and aims to minimize the SVG capacity to determine the installation capacity of SVG and reactors or capacitors;

[0072] Specifically, please refer to the appendix. Figure 2 As shown, the main transformer power supply zone 1 and main transformer power supply zone 2 are examples;

[0073] Furthermore, the daily active energy WpPcc and reactive energy WoPcc at PCC can be expressed as formula (3):

[0074]

[0075] In formula (3):

[0076] T represents the operating duration of the i-th time period.

[0077] Furthermore, the power factor λpcc at the PCC can be expressed by formula (4):

[0078]

[0079] Furthermore, when the number of subway trains is small and the capacitive reactive power of the cables in the power supply system is large, and the power factor at the PCC is lower than the preset threshold, the subway power supply system starts the reactive power compensation device to carry out the reactive power compensation process in order to make the PCC power factor meet the standard.

[0080] The reactive power compensation process is as follows:

[0081] When the main substation resources are shared, the power supply system structure will change before and after sharing. Therefore, it is necessary to comprehensively consider the power distribution of the power supply system before and after sharing the main substation resources, and combine different types of reactive power compensation equipment to achieve the power factor at the PCC while minimizing the investment cost of the power supply system.

[0082] Furthermore, using a linear programming method, the absolute value of the reactive power Qe compensated by the reactive power compensation device before resource sharing in the main substation, |Qe|, is used as the compensation amount of the reactive power compensation device SVG plus reactor or capacitor, with the constraint that the absolute value of the power factor at PCC is not less than 0.9.

[0083] Furthermore, the linear programming model before resource sharing in the main substation can be expressed as formula (5):

[0084]

[0085] In the resource sharing model, if the main substation needs to supply power to other lines, the active power WpPcc and reactive power Wopcc at PCC will change after resource sharing.

[0086] Based on formulas (1) to (5), the reactive power Qe that the reactive power compensation device needs to compensate after the main substation resource sharing can be obtained.

[0087] Furthermore, reactive power compensation is achieved by using SVG plus reactors or capacitors;

[0088] When Q and Qe are positive and negative the same, the smaller value between IQe| and |Qe,1| is selected as the installation capacity of the reactor or capacitor, and the difference between |Qe| and |Qe,| is used as the installation capacity of the SVG.

[0089] When Q and Qe are not positive or negative, the smaller value between |Q.| and lQe,1| is selected as the installed capacity of SVG, and the difference between IQe| and IQe,1| is used as the installed capacity of reactor or capacitor.

[0090] Furthermore, the reactive power compensation scheme is expressed by formulas (6) and (7):

[0091]

[0092] In formula (7):

[0093] Sx represents the installed capacity of the reactor or capacitor;

[0094] Ssg represents the installation capacity of the SVG.

[0095] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method of operating a metro power supply system based on sharing, characterized in that, Comprise: Step S1, the preset main substation in the subway power supply system and the preset time period of its power supply subarea are analyzed; Step S2, set the main transformer has j power supply subarea, according to the subway operation time characteristics, the whole day is divided into i time period; Wherein, i=1 is the peak operation period; i=2 is the low operation period; i=3 is the non operation period; The jth power supply subarea has M traction and depressor mixed traction and M depressor depressor; Wherein, m is the mth traction and depressor mixed traction in the jth power supply subarea connected with the main substation 35kV bus; N is the nth depressor in the jth power supply subarea connected with the main substation 35kV bus; Step S3, according to the number of subway train, vehicle basic attribute, power supply system structure diagram, power load design planning and other information, through the subway power supply system ac / dc power flow, the active power Pv, the reactive power Qv of the mth traction and depressor mixed traction connected with the main substation 35kV bus in the jth power supply subarea in the ith time period, the active power Pw and the reactive power Qw of the nth depressor connected with the main substation 35kV bus in the jth power supply subarea in the ith time period are calculated. Ppcc(i) and Qpcc(i) represent the active power and reactive power at PCC in the ith time period.

2. The shared-based subway power supply system operation method of claim 1, wherein The Ppcc(i) and the Qpcc(i) are represented as formula (1) and formula (2); Equation (1): Equation (2): In the formula (1) and the formula (2): Qe(i) represents the reactive power compensated by the reactive power compensation device in the ith time period; Qe(i) represents the positive representative inductive reactive power; Q(i) represents the negative representative capacitive reactive power.

3. The method of claim 1, wherein the shared metro power supply system is operated in a manner that, The total daily active power WpPcc and the total daily reactive power WoPcc at PCC can be represented by formula (3): In the formula (3): T, represents the operation time length of the ith time period.

4. The method of claim 3, wherein the method comprises: determining whether the power supply system is in the normal state; and if the power supply system is in the normal state, determining whether the power supply system is in the normal state. The power factor λpcc at PCC can be represented by formula (4):

5. The method of claim 4, wherein the method further comprises: determining whether the power supply system is in a normal state or an abnormal state; and if the power supply system is in the abnormal state, performing a power supply system recovery operation. When the number of subway trains is small, the capacitive reactive power in the power supply system is large, and the power factor at PCC is lower than the preset threshold, in order to make the power factor at PCC meet the standard, the subway power supply system starts the reactive power compensation process of the reactive power compensation device; The reactive power compensation process is: When the main substation resource is shared, the power supply system structure will change before and after sharing, so the power distribution of the power supply system before and after sharing the main substation resource needs to be considered comprehensively, and combined with different types of reactive power compensation equipment, the power factor at PCC meets the standard while the investment cost of the power supply system is minimized.

6. The shared-based subway power supply system operation method according to claim 5, wherein Using linear programming method, the absolute value |Qe| of the reactive power Qe compensated by the reactive power compensation device before the main substation resource sharing is taken as the compensation amount of the reactor or capacitor of the SVG, and the constraint condition is that the absolute value of the power factor at PCC is not less than 0.

9.

7. The shared-based subway power supply system operation method according to claim 6, wherein The linear programming model before the main substation resource sharing can be represented by formula (5): Wherein, under the resource sharing model, the main substation needs to supply power to other lines, so the active power WpPcc and the reactive power Wopcc at PCC will change after resource sharing; According to the formulas (1) to (5), the reactive power Qe that needs to be compensated by the reactive power compensation device after the resource sharing of the main transformer substation can be obtained.

8. The shared-based subway power supply system operation method of claim 7, wherein, The compensation mode of the SVG and the reactor or the capacitor is used for the reactive power compensation. When Q and Qe are positive or negative, the smaller value of |Qe| and |Qe,1| is selected as the installation capacity of the reactor or the capacitor, and the difference between |Qe| and |Qe,1| is selected as the installation capacity of the SVG. When Q and Qe are positive or negative, the smaller value of |Qe| and |Qe,1| is selected as the installation capacity of the SVG, and the difference between |Qe| and |Qe,1| is selected as the installation capacity of the reactor or the capacitor.

9. The shared-based subway power supply system operation method of claim 8, wherein, The reactive power compensation scheme is expressed in the form of expressions, which can be represented by formulas (6) and (7). Equation (6): Equation (7): In the formula (7), Sx represents the installation capacity of the reactor or the capacitor. Ssg represents the installation capacity of the SVG. ​

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