CN110299711A - A kind of Static Synchronous Series compensation system and method - Google Patents

Abstract

A static synchronous series compensation system and method, the solution includes: a primary circuit installed on a high potential platform and a secondary circuit installed in a control protection room; the high potential platform is equipotentially connected to the transmission line; the primary The loop is connected in series to the transmission line, and voltage compensation is performed on the transmission line; the secondary loop is connected to the primary loop, and a compensation command is issued to the primary loop according to the voltage loss value of the transmission line. The static synchronous series compensation system in this scheme does not require a series transformer or only needs a series transformer with a low insulation level, which greatly reduces the difficulty of insulation design of the series transformer, reduces the cost of the device, reduces the weight of the equipment, reduces the cost of the equipment, and greatly reduces the occupied area. In this scheme, the high-potential platform is connected to the equipotential connection of the transmission line, and the primary circuit is installed on the high-potential platform, which reduces the energy loss of the primary circuit caused by corona discharge and the electromagnetic interference of adjacent equipment.

Description

A static synchronous series compensation system and method

technical field

The invention relates to the technical field of flexible AC power transmission, in particular to a static synchronous series compensation system and method.

Background technique

At present, the distribution of power and load is reversed. Large-scale centralized wind power development is located in remote areas with light loads. Large-scale wind energy collection and transmission has become an inevitable choice. The weak transmission end of the power grid and the transient stability and dynamic stability of long-distance transmission corridors The problem is prominent and seriously threatens the safe and stable operation of the regional power grid. In order to promote the transmission and consumption of new energy, it is urgent to study effective measures to increase the transmission capacity of the system and enhance the stability of the system.

In addition, with the rapid development of large and medium-sized cities, the power load has increased sharply, and the long-distance transmission capacity has continued to increase, which puts forward higher requirements for the power supply capacity of transmission lines. The land acquisition and demolition of new transmission lines, as well as some social impacts arising therefrom, all put forward requirements for the construction of transmission lines. Therefore, how to improve the transmission capacity of existing transmission channels has important practical significance. On the other hand, 220kV and above power grids mostly use double-circuit lines for power supply. Due to the uneven distribution of regional loads, there is a phenomenon of overloaded lines in some areas. When one line is out of operation, the other line will be overloaded due to the influence of the line diameter, resulting in overall The power supply capacity cannot be fully utilized, which not only affects the scale efficiency of the power grid, but also leads to power cuts, which has a negative impact on the development of the national economy. Therefore, an effective power flow control method is urgently needed to improve the safety and stability of power grid operation.

For the above technical requirements, static synchronous series compensator provides an advanced and economical solution. SSSC adopts the voltage source commutation technology based on turn-off devices, which can be equivalent to a synchronous voltage source connected in series in the line. By injecting a voltage source orthogonal to the line current and with controllable amplitude, the equivalent of the transmission line can be changed. impedance. SSSC has the characteristics of strong power flow control ability, fast response speed, and compensation ability not affected by line current. Additional control damping can suppress power oscillation or subsynchronous oscillation. The use of SSSC can flexibly control the power flow of the line, greatly improve the limit of line power transmission, and its fast response of power control and additional damping control can better adapt to the characteristics of randomness and fluctuation of new energy output, which is a good way to improve the weak transmission end of the power grid. An effective means of transporting capacity from transmission corridors and enhancing system security and stability. In addition, SSSC has the advantages of capacitive and inductive bidirectional compensation, simple structure, and small footprint. It is suitable for large and medium-sized urban power grids that have high requirements for operational flexibility, reliability, and footprint. In the normal operation mode of the power grid, the SSSC performs equivalent capacitive compensation on the line, and increases the transmission capacity of the line according to the needs of the system; in the case of N-1 in the power grid, it performs inductive compensation, and the SSSC adjusts the line flow to avoid overload; during the transient process of the power grid, the SSSC passes The additional damping torque is controlled to suppress oscillation and improve the stability of the power grid. However, in the existing technology, the static synchronous series compensator is connected to the system through a series transformer with a high insulation voltage level, resulting in low integration of the device, large footprint, high insulation cost, and Less economical.

Contents of the invention

In order to solve the problems existing in the prior art that the static synchronous series compensator is connected to the system through a high insulation voltage level series transformer with low integration and large footprint, the present invention provides a static synchronous series compensator systems and methods.

The technical scheme provided by the invention is:

A static synchronous series compensation system, the system includes a primary circuit installed on a high potential platform and a secondary circuit installed in a control protection room;

The high potential platform is equipotentially connected to the transmission line;

The primary circuit is connected in series with the transmission line, and voltage compensation is performed on the transmission line;

The secondary circuit is connected to the primary circuit, and a compensation command is issued to the primary circuit according to the voltage loss value of the transmission line.

Preferably, the primary circuit includes: a plurality of converter modules;

All converter modules are connected in series to the transmission line.

Preferably, the primary loop further includes: a filter inductor;

After all the converter modules are connected in series, they are connected to the transmission line through the filter inductor.

Preferably, the primary circuit further includes: a filter inductor and a plurality of low-insulation transformers having the same number as the converter modules;

The plurality of low-insulation transformers are connected in series through the filter inductor to the transmission line;

Each converter module is respectively coupled with a low insulation transformer.

Preferably, the primary circuit further includes: a low insulation transformer;

The converter modules are sequentially connected in series and connected in parallel on the secondary side of the low insulation transformer;

The primary side of the low insulation transformer is connected in series in the transmission line.

Preferably, the converter module includes:

Two IGBT bridge arms, supporting capacitors and mechanical switches;

The IGBT bridge arms are connected in parallel to the supporting capacitor, and the midpoint of the two IGBT bridge arms forms an output end;

The mechanical switch is connected in parallel between the output ends, and is used to control the bypass or input of the ICBT bridge arm.

Preferably, the converter module further includes: two thyristors;

The two thyristors are connected in reverse parallel and connected to the output terminal of the converter module, so as to quickly bypass the IGBT bridge arm when the IGBT bridge arm fails.

Preferably, the primary loop further includes: an instruction receiving unit;

The instruction receiving unit is connected with the mechanical switch, and is used for controlling the on-off of the mechanical switch according to the compensation instruction of the secondary circuit.

Preferably, the high-potential platform includes a low-grade insulator;

The primary circuit is supported and installed on a high-potential platform through low-grade insulators.

A static synchronous series compensation method, comprising:

When the voltage of the transmission line is lost, the secondary circuit installed in the control protection room formulates compensation instructions according to the voltage loss value and sends it to the primary circuit installed on the high potential platform;

The primary circuit performs voltage compensation on the transmission line equipotentially connected to the high potential platform according to the compensation instruction.

Preferably, the secondary circuit installed in the control protection room formulates compensation instructions according to the voltage loss value, including:

The secondary circuit determines the number of converter modules to be put into the primary circuit according to the voltage loss value of the transmission line, and formulates a compensation instruction.

Preferably, the primary circuit performs voltage compensation on the transmission line equipotentially connected to the high-potential platform according to the compensation instruction, including:

The signal receiving unit in the primary circuit controls the mechanical switch of the converter module in the primary circuit to close according to the compensation instruction, and bypasses the IGBT bridge arm in the current converter module;

The commutation module put into use performs voltage compensation on the transmission line.

Compared with prior art, the beneficial effect of the present invention is:

The technical solution provided by the present invention includes: a primary circuit installed on a high-potential platform and a secondary circuit installed in a control protection room; the high-potential platform is equipotentially connected to the transmission line; the primary circuit is connected in series to the transmission line In the method, voltage compensation is performed on the transmission line; the secondary circuit is connected to the primary circuit, and a compensation command is issued to the primary circuit according to a voltage loss value of the transmission line. The static synchronous series compensation system in this scheme does not need a series transformer or only needs a series transformer with a low insulation level, which greatly reduces the difficulty of insulation design of the series transformer, reduces the cost of the device, reduces the weight of the equipment, reduces the cost of the equipment, and greatly reduces the occupied area. In this scheme, the high-potential platform is connected to the equipotential connection of the transmission line, and the primary circuit is installed on the high-potential platform, which reduces the energy loss of the primary circuit caused by corona discharge and the electromagnetic interference of adjacent equipment.

Description of drawings

Fig. 1 is a kind of static synchronous series compensation system structural diagram of the present invention;

Fig. 2 is a connection structure diagram of scheme one in the embodiment of the present invention;

Fig. 3 is the connection structure diagram of scheme two in the embodiment of the present invention;

Fig. 4 is the connection structure diagram of scheme three in the embodiment of the present invention;

Detailed ways

In order to better understand the present invention, the content of the present invention will be further described below in conjunction with the accompanying drawings and examples.

Example 1:

This embodiment provides a static synchronous series compensation system, which is installed in a substation. The system structure diagram is shown in Figure 1, wherein the primary circuit components are installed on the high potential platform; the secondary components are installed in the control protection room; this The system also includes: a cooling water machine and a heat exchanger, the cooling water machine is installed in the water cooling room; the heat exchanger is installed outdoors.

There are multiple composition schemes for the primary circuit components:

Option 1: Static synchronous series compensator without access transformer.

This scheme can be used when the short-circuit capacity of the system is small, the equipment occupies an area or the cost control requirements are strict.

As shown in Figure 2, the primary loop is composed of filter inductors and N converter modules connected in series, which are directly connected to the transmission line in series. Filter inductors and series converter modules are supported on high-potential platforms by insulators with low insulation grades. Each series-connected converter module is composed of an H-bridge circuit. The main components are two IGBT-based bridge arms connected in parallel with the supporting capacitor. The midpoint of the two bridge arms is the output end of the converter module. Thyristors are connected in parallel, and parallel mechanical switches or contactors can also be selected between the output ends of the converter modules. The converter module is also designed with an energy harvesting circuit and a module measurement control protection unit, which can realize line energy harvesting and control and protection of the circuit module.

Among them, the H-bridge is the power element part of the converter, which realizes the voltage output; the supporting capacitor provides the DC supporting voltage for the converter; The inverter exits; the mechanical switch or contactor realizes the reliable bypass of the inverter; the energy harvesting circuit realizes the supply of energy to the high-potential inverter control protection monitoring unit.

Scheme 2: Distributed static synchronous series compensator.

This scheme can be used when the short-circuit current of the system is large and the volume or weight of the device is strictly controlled.

As shown in Figure 3, the primary circuit is composed of an optional filter inductor and N converter modules connected to a distributed transformer with a low insulation level. The optional filter inductor and the primary side of the distributed transformer are directly connected in series to the power transmission line. Each series-connected converter module is composed of an H-bridge circuit. The main components are two IGBT-based bridge arms connected in parallel with the supporting capacitor. The midpoint of the two bridge arms is the output end of the converter module. Thyristors are connected in parallel, and parallel mechanical switches or contactors can also be selected between the output ends of the converter modules. The output terminal of the converter module is connected in parallel with the secondary side of the distributed transformer. The converter module is also designed with an energy harvesting circuit and a module measurement control protection unit, which can realize line energy harvesting and control and protection of the circuit module.

Scheme 3: The series transformer is connected to the static synchronous series compensator.

This scheme can be adopted when the short-circuit current of the system is large and the volume or weight of the device is not strictly controlled.

As shown in Figure 4, the primary circuit is composed of a series transformer with a low insulation level and N converter modules connected in series, and the primary side of the series transformer with a low insulation level is directly connected to the transmission line in series. Each series-connected converter module is composed of an H-bridge circuit. The main components are two IGBT-based bridge arms connected in parallel with the supporting capacitor. The midpoint of the two bridge arms is the output end of the converter module. Thyristors are connected in parallel, and parallel mechanical switches or contactors can also be selected between the output ends of the converter modules. After the N converter modules are connected in series, the output terminal is connected in parallel with the secondary side of the series transformer with low insulation level. The converter module is also designed with an energy harvesting circuit and a module measurement control protection unit, which can realize line energy harvesting and control and protection of the circuit module.

The control, protection and monitoring electronic circuit of the secondary part of the static synchronous series compensator based on the high-potential platform structure communicates with the primary part through optical fiber. If the converter valve adopts water-cooling mode, the water distribution pipeline of the converter valve is led from the high-potential platform through an insulating material water pipe. Connect to the water machine and heat exchanger. The insulating material can be made of PVDF, PPR and other materials.

Embodiment two:

This embodiment provides a static synchronous series compensation system, including: a primary circuit installed on a high potential platform and a secondary circuit installed in a control protection room;

The high potential platform is equipotentially connected to the transmission line;

The primary circuit is connected in series with the transmission line, and voltage compensation is performed on the transmission line;

The secondary circuit is connected to the primary circuit, and a compensation command is issued to the primary circuit according to the voltage loss value of the transmission line.

The primary circuit includes: a plurality of converter modules;

All converter modules are connected in series to the transmission line.

The primary loop also includes: a filter inductor;

After all the converter modules are connected in series, they are connected to the transmission line through the filter inductor.

The primary circuit further includes: a filter inductor and a plurality of low-insulation transformers having the same number as the converter modules;

The plurality of low-insulation transformers are connected in series through the filter inductor to the transmission line;

Each converter module is respectively coupled with a low insulation transformer.

The primary circuit also includes: a low insulation transformer;

The converter modules are sequentially connected in series and connected in parallel on the secondary side of the low insulation transformer;

The primary side of the low insulation transformer is connected in series in the transmission line.

The converter module includes:

Two IGBT bridge arms, supporting capacitors and mechanical switches;

The IGBT bridge arms are connected in parallel to the supporting capacitor, and the midpoint of the two IGBT bridge arms forms an output end;

The mechanical switch is connected in parallel between the output ends, and is used to control the bypass or input of the ICBT bridge arm.

The converter module also includes: two thyristors;

The two thyristors are connected in reverse parallel and connected to the output terminal of the converter module, so as to quickly bypass the IGBT bridge arm when the IGBT bridge arm fails.

The primary loop also includes: an instruction receiving unit;

The instruction receiving unit is connected with the mechanical switch, and is used for controlling the on-off of the mechanical switch according to the compensation instruction of the secondary circuit.

The high potential platform includes a low grade insulator;

The primary circuit is supported and installed on a high-potential platform through low-grade insulators.

Embodiment three:

This embodiment provides a static synchronous series compensation method, including:

When the voltage of the transmission line is lost, the secondary circuit installed in the control protection room formulates compensation instructions according to the voltage loss value and sends it to the primary circuit installed on the high potential platform;

The primary circuit performs voltage compensation on the transmission line equipotentially connected to the high potential platform according to the compensation instruction.

The secondary circuit installed in the control and protection room formulates compensation instructions according to the voltage loss value, including:

The secondary circuit determines the number of converter modules to be put into the primary circuit according to the voltage loss value of the transmission line, and formulates a compensation instruction.

According to the compensation instruction, the primary circuit performs voltage compensation on the transmission line equipotentially connected with the high potential platform, including:

The signal receiving unit in the primary circuit controls the mechanical switch of the converter module in the primary circuit to close according to the compensation instruction, and bypasses the IGBT bridge arm in the current converter module;

The commutation module put into use performs voltage compensation on the transmission line.

Apparently, the described embodiments are some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Those skilled in the art should understand that the embodiments of the present application may be provided as methods, systems, or computer program products. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

The present application is described with reference to flowcharts and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present application. It should be understood that each procedure and/or block in the flowchart and/or block diagram, and a combination of procedures and/or blocks in the flowchart and/or block diagram can be realized by computer program instructions. These computer program instructions may be provided to a general purpose computer, special purpose computer, embedded processor, or processor of other programmable data processing equipment to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing equipment produce a An apparatus for realizing the functions specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to operate in a specific manner, such that the instructions stored in the computer-readable memory produce an article of manufacture comprising instruction means, the instructions The device realizes the function specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions can also be loaded onto a computer or other programmable data processing device, causing a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process, thereby The instructions provide steps for implementing the functions specified in the flow chart or blocks of the flowchart and/or the block or blocks of the block diagrams.

The above are only embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention are included in the pending application of the present invention. within the scope of the claims.

Claims (12)

1. a kind of Static Synchronous Series compensation system, which is characterized in that the system comprises one be installed on high potential platform Minor loop protects indoor secondary circuit with control is installed on；

The high potential platform is connect with electric transmission line equipotential；

The primary circuit is serially connected in transmission line of electricity, carries out voltage compensation to the transmission line of electricity；

The secondary circuit is connect with the primary circuit, according to the voltage missing values of the transmission line of electricity, to described primary time Road issues compensating instruction.

2. the system as claimed in claim 1, which is characterized in that the primary circuit, comprising: multiple change of current modules；

It is accessed in transmission line of electricity after all change of current module series windings.

3. system as claimed in claim 2, which is characterized in that the primary circuit, further includes: filter inductance；

It is accessed in transmission line of electricity after all change of current module series windings by filter inductance.

4. system as claimed in claim 2, which is characterized in that the primary circuit, further includes: filter inductance and changed with described The identical multiple low insulation transformers of flow module quantity；

It is accessed in transmission line of electricity after the multiple low insulation transformer series by filter inductance；

Each change of current module is transformer coupled with a low insulation respectively.

5. system as claimed in claim 2, which is characterized in that the primary circuit, further includes: low insulation transformer；

After the change of current module is sequentially connected in series, it is connected in parallel on the secondary side of the low insulation transformer；

The primary side of the low insulation transformer is connected in the transmission line of electricity.

6. such as the described in any item systems of claim 2 to 5, which is characterized in that the change of current module, comprising:

Two IGBT bridge arms, Support Capacitor and mechanical switch；

The IGBT bridge arm and the Support Capacitor simultaneously connect, and the midpoint of two IGBT bridge arms constitutes output end；

The mechanical switch is attempted by between the output end, for controlling the bypass or investment of the ICBT bridge arm.

7. system as claimed in claim 6, which is characterized in that the change of current module, further includes: two thyristors；

The output end of the change of current module is attempted by after two thyristor reverse parallel connections, for working as the IGBT bridge arm failure When, quickly bypass the IGBT bridge arm.

8. system as claimed in claim 6, which is characterized in that the primary circuit, further includes: instruction receiving unit；

Described instruction receiving unit is connect with the mechanical switch, for the compensating instruction according to the secondary circuit, controls institute State the on-off of mechanical switch.

9. the system as claimed in claim 1, which is characterized in that the high potential platform includes inferior grade insulator；

The primary circuit is installed on high potential platform by the support of inferior grade insulator.

10. a kind of Static Synchronous Series compensation method characterized by comprising

When the voltage of transmission line of electricity missing, control protection indoor secondary circuit is installed on according to voltage missing values, formulates compensation Instruction, is sent to the primary circuit being installed on high potential platform；

The primary circuit carries out voltage benefit according to the compensating instruction, to the transmission line of electricity of high potential platform equipotential link It repays.

11. method as claimed in claim 10, which is characterized in that the control protection indoor secondary circuit that is installed on is according to electricity Missing values are pressed, compensating instruction is formulated, comprising:

The secondary circuit determines the change of current module for needing to put into primary circuit according to the voltage missing values of the transmission line of electricity Quantity, and formulate compensating instruction.

12. method as claimed in claim 11, which is characterized in that the primary circuit according to the compensating instruction, to height The transmission line of electricity of potential plateau equipotential link carries out voltage compensation, comprising:

Signal receiving unit in the primary circuit controls the machinery of change of current module in primary circuit according to the compensating instruction It closes the switch, the IGBT bridge arm in current commutation module is bypassed；

The change of current module to come into operation carries out voltage compensation to transmission line of electricity.