CN103986159A - Installation circuit of unified power flow controller in substation with multiple lines - Google Patents

Abstract

The invention discloses an installation circuit of a unified power flow controller in a substation with multiple lines, which is mainly used in a substation with multiple lines, including several substation lines, a main busbar of a substation, an auxiliary busbar of a substation, and a unified power flow controller UPFC , UPFC bus, several circuit breakers and several isolating switches. By changing the closed and disconnected state of the isolating switch, the power flow controller can compensate the voltage of any substation line and control the power flow of the line under the normal operation of the power grid, and flexibly switch between different lines at the same time; Under certain circumstances, the power flow controller can control the power flow of an independent circuit composed of any two substation lines to realize the emergency power flow control function. The invention realizes the switching control of power flows of multiple lines by a single unified power flow controller, which not only saves investment, improves the economical efficiency of power grid operation, but also enhances the flexibility of the unified power flow controller, which contributes to the safe and stable operation of the power grid.

Description

Installation circuit of unified power flow controller in substation with multiple lines

technical field

The invention relates to an installation circuit of a unified power flow controller in a substation with multiple lines, belonging to the technical field of power grid control.

Background technique

Before the application of flexible AC transmission system (FACTS) technology, the power grid adopted traditional mechanical control methods, which had limitations such as slow response speed, inability to operate frequently, discrete control functions, etc., and were basically only suitable for steady-state power flow or voltage control. State and dynamic stability lack sufficient control capabilities, so the system generally leaves a large stability margin during operation, and it is difficult to make full use of the power transmission capacity of power equipment.

Unified Power Flow Controller (UPFC) is a new generation of flexible AC transmission (FACTS) device with the most powerful functions and the most superior characteristics. , all the functions of voltage regulation, series compensation and phase shifting can be realized separately or simultaneously only by changing the control law. The UPFC device can be regarded as a static synchronous (STATCOM) device and a static synchronous series compensator (SSSC) device connected in parallel on the DC side, which can simultaneously and quickly and independently control the active power and reactive power in the transmission line , so that UPFC has a four-quadrant operation function that STATCOM and SSSC devices do not have. UPFC can effectively control the power flow distribution of the line and improve the stability of the power system.

However, UPFC is usually installed on a fixed line and can only control the active and reactive power flowing through the line. When the power flow control of multiple lines is required during the operation of the power system, a corresponding number of UPFCs must be installed, which increases investment and operating costs.

Contents of the invention

Aiming at the deficiency of the existing unified power flow control installation method, the present invention provides an installation circuit of a unified power flow controller in a substation with multiple lines, which is mainly used in a substation with multiple lines, and realizes a single UPFC for multiple lines The function of power flow control effectively reduces operating costs and improves the stability of power grid operation.

In order to achieve the above object, the technical scheme adopted in the present invention is:

The installation circuit of the unified power flow controller in the substation with multiple lines, including several substation lines, substation main busbar, substation auxiliary busbar, unified power flow controller UPFC, UPFC busbar, several circuit breakers and several isolating switches; the substation The main bus is divided into section I and section II, and the middle is connected by an isolating switch; the auxiliary bus of the substation is divided into sections III and IV, and the middle is connected by an isolating switch; the main bus and the auxiliary bus of the substation are connected by a bus tie switch; Each line of the substation is connected to the isolation switch and the circuit breaker in turn, and then connected to section I or section II of the main bus of the substation through an isolation switch, and connected to section III or section IV of the auxiliary bus of the substation through another isolation switch. An isolating switch is connected to section V or section VI of the UPFC busbar; the UPFC busbar is divided into section V busbar and section VI busbar, and one side of the section V busbar is connected to the incoming line terminal of the unified power flow controller through a circuit breaker; One side of the section VI busbar is connected to the outlet terminal of the unified power flow controller through a circuit breaker, and the other side of the section VI busbar is connected to the section II busbar of the main busbar of the substation and section IV section of the auxiliary busbar of the substation through a disconnector connect.

The aforementioned unified power flow controller includes a transmission line, a transformer 1 and a transformer 2, a converter 1 and a converter 2, an isolating switch 1 and an isolating switch 2, a capacitor and a control system; the isolating switch 1 is installed on the transmission line and the transformer 1; the isolating switch 2 is installed between the transformer 2 and the converter 2; the DC side of the converter 1 and the converter 2 are connected through a capacitor; the converter 1 and the converter 2 The AC side is connected to the control system.

Compared with the existing single UPFC that can only perform power flow control on one line fixedly, the beneficial effects achieved by the present invention are:

(1) When the power grid is in normal operation, through the cooperation between UPFC bus, substation bus, multiple circuit breakers and isolating switches, a single UPFC can control the power flow of any substation line, and can flexibly switch between different lines , not only can save investment, improve the economy of power grid operation, but also increase the flexibility of the unified power flow controller.

(2) In the event of an emergency fault in the power grid, any two lines can form an independent operating loop through the cooperation between the UPFC busbar and related circuit breakers and isolating switches, and the emergency power flow control of the loop is realized through the UPFC device, which improves the Stability and safety of the power grid under emergency fault conditions.

Description of drawings

Fig. 1 is the installation circuit wiring diagram of the present invention;

Fig. 2 is a schematic diagram of the internal structure of the unified power flow controller of the present invention;

Fig. 3 is the specific wiring diagram when the unified power flow controller of the present invention controls the power flow of circuit 1;

Fig. 4 is a schematic diagram of substation operation in the case of Fig. 3;

Fig. 5 is the specific wiring diagram of the power flow of the independent loop formed by the unified power flow controller of the present invention controlled by line 1 and line 2;

Fig. 6 is a schematic diagram of substation operation in the case of Fig. 5 .

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1, the installation circuit of the unified power flow controller in the substation with multiple lines of the present invention includes several substation lines, the main busbar of the substation, the auxiliary busbar of the substation, the unified power flow controller UPFC, the UPFC busbar, and several circuit breakers and several isolating switches; the UPFC bus is divided into Ⅴ-section bus and Ⅵ-section bus, and isolation switches are installed between the UPFC bus and all lines in the substation, as shown in Figure 1, between line 1 and the Ⅴ-section bus of the UPFC bus The connection between line 2 and section V bus of UPFC bus is connected through isolation switch 202, ..., the connection between line M and section VI bus of UPFC bus is connected through isolation switch 20M. One side of the busbar in section V is connected to the incoming line end of the unified power flow controller through circuit breaker 1; one side of the busbar in section VI is connected to the outgoing line end of the unified power flow controller through circuit breaker 2. Section VI of the UPFC bus is connected to section II of the main bus of the substation through an isolating switch 302 , and section IV of the auxiliary bus of the substation is connected through an isolating switch 301 .

The substation of the present invention comprises several lines, such as line 1, line 2,..., line M among Fig. 1, positive busbar, auxiliary busbar, several isolating switches, such as isolating switch _L101 , isolating switch among Fig. 1 L ₁ 02, isolation switch L ₁ 03, ..., isolation switch L _M 01, isolation switch L M 02, isolation switch L _{M 03} , several circuit breakers, such as circuit breaker L ₁ and circuit breaker L ₂ in Figure 1 , ..., circuit breaker L _M . The main busbar of the substation is divided into section I and section II, and the middle is connected by a disconnector 401; the auxiliary busbar of the substation is divided into section III and section IV, and the middle is connected by a disconnector 402; the main and auxiliary busbars are connected by a bus tie switch 4; the substation Each line is connected to the isolation switch and circuit breaker in turn, and then connected to section I or section II of the main bus through an isolation switch, connected to section III or section IV of the auxiliary bus through another isolation switch, and connected to UPFC through an isolation switch Section V or Section VI of the busbar is connected; all lines of the substation can be externally connected to the same or different busbars. Taking line 1 as an example, line 1 is connected to isolation switch L ₁ 01 and circuit breaker L ₁ in sequence, and then connected to section I of the main bus through isolation switch L ₁ 02, and connected to section III of auxiliary bus through isolation switch L ₁ 03. It is connected to section V of the UPFC bus through the isolating switch 201, and the connection mode of the other lines is similar to that of line 1.

As shown in Figure 2, the unified power flow controller of the present invention includes transmission line, transformer 1 and transformer 2, converter 1 and converter 2, isolating switch 1 and isolating switch 2, capacitor and control system; Wherein isolating switch 1 Installed between the transmission line and the transformer 1; the isolation switch 2 is installed between the transformer 2 and the converter 2; the DC side of the converter 1 and the converter 2 are connected through a capacitor; the converter 1 and the converter 2 The AC side is connected to the control system. The entire unified power flow controller is equivalent to a static synchronous compensator (STATCOM) and a static synchronous series compensator (SSSC) connected by DC side capacitors.

As shown in FIG. 3 , it is a wiring diagram when the unified power flow controller of the present invention is used to control the power flow of line 1 . Line 1 is connected to isolation switch L ₁ 01 and circuit breaker L ₁ in sequence, and then connected to section V of the UPFC bus through isolation switch 201. The isolation switch 201 is in the closed state, and connected to section I of the main bus of the substation through isolation switch L ₁ 02. The isolating switch L ₁ 03 is connected to section III of the auxiliary bus bar of the substation, and the isolating switch L ₁ 02 and the isolating switch L ₁ 03 are in the disconnected state. Line 2 is connected to isolation switch L ₂ 01 and circuit breaker L ₂ in sequence, and then connected to section V of the UPFC bus through isolation switch 202. The isolation switch 202 is in the disconnected state, and connected to section I of the main bus of the substation through isolation switch L ₂ 02. The isolation switch L ₂ 03 is connected to section III of the auxiliary bus bar of the substation, the isolation switch L ₂ 02 is in the closed state, and the isolation switch L ₂ 03 is in the open state. The wiring of other lines is similar to that of line 2. The isolating switches connected to the main busbar are all in the closed state, and the isolating switches connected to the auxiliary busbar and UPFC busbar are all in the open state. The isolating switches L ₁ 01, L ₂ 01, ..., L _M 01 are all in closed state. The isolating switch 302 between the UPFC bus section VI and the main bus section II is in the closed state, the isolating switch 301 between the UPFC bus section VI and the auxiliary bus section IV is in the open state, and the substation main bus section I and II section The isolating switch 401 is in the closed state, and the isolating switch 402 between the sub-section III and IV of the substation sub-bus is in the open state. The internal isolating switch 1 and isolating switch 2 of the unified power flow controller are both in the closed state. In the case of this circuit connection, the unified power flow controller realizes the power flow control of line 1.

FIG. 4 schematically shows the operation schematic diagram of the substation when the unified power flow controller is used to control the line 1 .

As shown in Figure 5, when an emergency fault occurs in the power grid, the specific wiring diagram when the unified power flow controller is used to control the power flow of an independent loop composed of any two lines. Taking the power flow of independent lines composed of control lines 1 and 2 as an example, line 1 is connected to isolation switch L ₁ 01 and circuit breaker L ₁ in sequence, and then connected to section V of the UPFC bus through isolation switch 201. The isolating switch L ₁ 02 is connected to section I of the main bus of the substation, and is connected to section III of the auxiliary bus of the substation through the isolating switch L ₁ 03. The isolating switch L ₁ 02 and the isolating switch L ₁ 03 are in the disconnected state. Line 2 is connected to isolation switch L ₂ 01 and circuit breaker L ₂ in sequence, and then connected to section V of the UPFC bus through isolation switch 202. The isolation switch 202 is in the disconnected state, and connected to section I of the main bus of the substation through isolation switch L ₂ 02. The isolation switch L ₂ 03 is connected to section III of the auxiliary bus bar of the substation, the isolation switch L ₂ 02 is in the closed state, and the isolation switch L ₂ 03 is in the open state. The line M is connected to the isolating switch L _M 01 and the circuit breaker L _M in turn, and then connected to the section VI of the UPFC bus through the isolating switch 20M. The isolating switch 20M is in the disconnected state, and connected to the section II of the main bus of the substation through the isolating switch L _M 02 , through the isolation switch L _M 03 to connect with sub-substation auxiliary bus section IV, the isolation switch L _M 02 is in the open state, and the isolation switch L _M 03 is in the closed state. The connection mode of the other lines is similar to that of line M. The isolating switches connected to the auxiliary bus are all in the closed state, and the isolating switches connected to the main bus and the UPFC bus are all in the open state. The isolating switches L ₁ 01, L ₂ 01, ..., L _M 01 are all in closed state. The isolating switch 302 between the UPFC bus section VI and the main bus section II is in the closed state, the isolating switch 301 between the UPFC bus section VI and the auxiliary bus section IV is in the open state, and the substation main bus section I and II section The isolating switch 401 is in the closed state, and the isolating switch 402 between the sub-section III and IV of the substation sub-bus is in the open state. The internal isolating switch 1 and isolating switch 2 of the unified power flow controller are both in the closed state. In this circuit wiring situation, the unified power flow controller realizes the control of the independent loop power flow composed of lines 1 and 2.

Fig. 6 schematically shows the operation schematic diagram of the substation when the unified power flow controller performs power flow control on the independent loop composed of lines 1 and 2 when an emergency fault occurs in the power grid.

Claims (2)

1. The installation circuit of the unified power flow controller in the substation with multiple lines is characterized in that it includes several substation lines, the main busbar of the substation, the auxiliary busbar of the substation, the unified power flow controller UPFC, the UPFC busbar, several circuit breakers and several Isolating switch; the main busbar of the substation is divided into section I and section II, and the middle is connected by an isolating switch; the auxiliary busbar of the substation is divided into section III and section IV, and the middle is connected by an isolating switch; between the main busbar and the auxiliary busbar of the substation Connected by a bus tie switch; each line of the substation is connected to the isolation switch and circuit breaker in turn, and then connected to section I or section II of the main bus of the substation through an isolation switch, and connected to section III of the auxiliary bus of the substation through another isolation switch Or the section IV connection is connected to section V or section VI of the UPFC bus through an isolating switch; the UPFC bus is divided into section V bus and section VI bus, and one side of the section V bus is connected to the unified power flow controller through a circuit breaker The incoming terminal is connected; one side of the section VI busbar is connected to the outgoing line terminal of the unified power flow controller through a circuit breaker, and the other side of the section VI busbar is connected to the section II busbar of the substation main busbar and the IV section of the substation auxiliary busbar They are connected through isolating switches. 2. the installation circuit of unified power flow controller in the substation with multi-line according to claim 1, is characterized in that, described unified power flow controller comprises transmission line, transformer 1 and transformer 2, converter 1 and converter Device 2, isolating switch 1 and isolating switch 2, capacitor and control system; the isolating switch 1 is installed between the transmission line and the transformer 1; the isolating switch 2 is installed between the transformer 2 and the converter 2; the The DC side of the converter 1 and the converter 2 are connected through a capacitor; the AC side of the converter 1 and the converter 2 is connected to a control system.