JP3243444U - Thermal power unit frequency modulation system and device - Google Patents

Abstract

A thermal power unit frequency modulation system and apparatus with fast response speed and high unit ramp rate in performing frequency modulation tasks. A thermal power generation unit frequency modulation system controls the operating state of a thermal power grid interconnection unit for controlling active power output by a generator and a reserve energy storage device based on a frequency modulation command. a pre-transformer standby energy storage unit 2 for responding to frequency modulation commands, and the high voltage side is connected to the generator, usually for responding to frequency modulation commands by controlling the operating state of the energy storage device high voltage in-station transformer ordinary energy storage unit 3. [Selection drawing] Fig. 1

Description

TECHNICAL FIELD The present invention relates to the technical field of power transmission, and more particularly to a thermal power unit frequency modulation system and device.

The increasing influx of wind power generation and conventional energy storage, the rapid development of interconnected large-scale power grids, high-capacity generation and remote transmission have made the frequency modulation task even heavier in power systems. In related art, frequency modulated power supply is mainly thermal power generation unit and hydro power generation unit, and the working principle is to track the change of system frequency by adjusting the effective output of the unit. However, thermal power units usually have problems such as long response time lag, low unit ramp rate, power grid scheduling instructions cannot be accurately tracked, and adjustment time delays, adjustment deviations, etc. and reversal of adjustment. In addition, when the thermal power unit operates with frequent power conversion, the fatigue and wear of the unit equipment will be aggravated to some extent, affecting the service life of the unit.

SUMMARY OF THE INVENTION The present invention aims to solve one of the technical problems in the related art to some extent.

Therefore, the first object of the present invention is to solve the technical problem of long response time lag and low ramp rate of the unit when the thermal power unit performs the frequency modulation task. It is to provide a system.

A second object of the present invention is to provide a thermal power unit frequency modulation system so as to solve the technical problem that the thermal power unit cannot track the power grid scheduling instructions.

A third object of the present invention is to provide a thermal power unit frequency modulation device.

To achieve the above objectives, a thermal power generation unit frequency modulation system provided by an embodiment of the first aspect of the present invention comprises a thermal power grid interconnection unit, a standby transformer standby energy storage unit, and a high voltage station transformer. an energy storage unit, wherein the thermal power grid interconnection unit comprises a power grid transmission bus and a generator feeding the power grid transmission bus; the standby transformer standby energy storage unit comprises a thermal power unit standby transformer and a reserve energy storage device, the high voltage station transformer ordinary energy storage unit has an ordinary energy storage device, the thermal power grid interconnection unit is output by the generator according to the frequency modulation command and said pre-transformer standby energy storage unit responds to said frequency modulation command by controlling the operating state of said standby energy storage device, said thermal power unit standby high voltage side of said connected to a power grid transmission bus, the low side A branch of the thermal power unit standby transformer is connected to the generator, the high voltage side of the high voltage station transformer normal energy storage unit is connected to the generator, the normal Responding to the frequency modulation command by controlling the operating state of the energy storage device.

Optionally, in one embodiment of the present invention, the thermal power grid interconnection unit further comprises a generator main transformer, the outlet of the generator is connected to the low voltage side of the generator main transformer, The high voltage side of the generator main transformer is connected to the power grid transmission bus.

Optionally, in one embodiment of the present invention, the pre-transformer reserve energy storage unit comprises: a pre-transformer low side A branch bus; a pre-transformer low side B branch bus; a pre-transformer low side A branch circuit breaker; further comprising a standby energy storage step-up transformer, a standby energy storage grid interconnection breaker, and a standby energy storage converter, wherein the low voltage side of the thermal power unit standby transformer is the standby transformer low voltage side A branch bus and the standby transformer the pre-transformer low-voltage side A branch bus is connected to the outlet of the generator by the pre-transformer low-voltage side A-branch circuit breaker, and the pre-transformer low-voltage side B branch bus is is connected to the reserve energy storage step-up transformer, the reserve energy storage step-up transformer is connected to the AC side of the reserve energy storage converter by the reserve energy storage grid interconnection breaker, and the DC side of the reserve energy storage converter is connected to the reserve energy storage device;

Optionally, in one embodiment of the present invention, the high voltage substation transformer normal energy storage unit comprises a split winding high voltage substation transformer, a 6 kV substation A branch, a 6 kV substation B branch, a 6 kV substation A branch circuit breaker, a 6 kV substation A branch load, 6 kV on-site B branch circuit breaker, 6 kV on-site B branch load, normal energy storage PET grid interconnection circuit breaker, PET, normal energy storage PET low voltage side circuit breaker, and normal energy storage converter, and the split winding The high-voltage side of the line high-voltage station transformer is connected to the outlet of the generator, the low-voltage side of the split-winding high-voltage station transformer is connected to the 6 kV in-station A branch and the 6 kV in-station B branch, and the 6 kV in-station A branch is connected to the 6 kV on-site A branch load by the 6 kV on-site A branch circuit breaker, the 6 kV on-site B branch is connected to the 6 kV on-site B branch load by the 6 kV on-site B branch circuit breaker, and the high voltage side of the PET is connected to the connected to the 6 kV on-site B branch by a normal energy storage PET grid interconnection circuit breaker; the low voltage side of the PET is connected to the AC side of the normal energy storage converter by the normal energy storage PET low voltage side circuit breaker; The DC side of the storage converter is connected to the conventional energy storage device.

Optionally, in one embodiment of the present invention, the PET is a normal energy storage PET high voltage DC-AC converter, a normal energy storage PET high voltage side filter capacitor, a normal energy storage PET high frequency DC-DC transformer, a normal energy storage PET a low voltage side filter capacitor, and a conventional energy storage PET low voltage AC-DC converter, wherein the AC side of the conventional energy storage PET high voltage DC-AC converter is connected to the conventional energy storage PET grid interconnection circuit breaker; The high voltage side of the storage PET high frequency DC-DC transformer is connected to the DC side of the conventional energy storage PET high voltage DC-AC converter by the conventional energy storage PET high voltage side filter capacitor, and the high voltage side of the conventional energy storage PET low voltage AC-DC converter. The DC side of the conventional energy storage PET low voltage side filter capacitor is connected to the low voltage side of the conventional energy storage PET high frequency DC-DC transformer, and the AC side of the conventional energy storage PET low voltage AC-DC converter is connected to the conventional energy storage PET. Connected to the low voltage side circuit breaker.

Optionally, in one embodiment of the invention, the PET is constructed with modular multi-level converter MMC power electronics.

Thus, a thermal power unit frequency modulation system provided by an embodiment of the first aspect of the present invention comprises a thermal power grid interconnection unit, a standby transformer standby energy storage unit, and a high voltage station transformer normal energy storage unit. , the thermal power generation grid interconnection unit has a power grid transmission bus and a generator feeding the power grid transmission bus, and the standby transformer standby energy storage unit comprises a thermal power unit standby transformer and a standby energy storage device. wherein the high voltage station transformer normal energy storage unit has a normal energy storage device, and the thermal power grid interconnection unit controls the active power output by the generator according to the frequency modulation command. and said standby transformer standby energy storage unit responds to said frequency modulation command by controlling the operating state of said standby energy storage device, wherein the high voltage side of said thermal power unit standby transformer is connected to said power grid transmission; the high voltage side of the high voltage station transformer normal energy storage unit is connected to the generator and the normal energy storage It responds to said frequency modulation commands by controlling the operational state of the device. The present invention uses a standby transformer standby energy storage unit to control the operating state of the standby energy storage device to respond to frequency modulation commands, and a high voltage station transformer normal energy storage unit to control the normal energy storage device. By controlling the operating state of the thermal power unit frequency modulation system to respond to the frequency modulation command, the response speed of the thermal power unit frequency modulation system in performing frequency modulation tasks and the ramp rate of the unit can be improved. The present invention can also reduce the number of times of power conversion and operation. This can reduce the degree of fatigue and wear of the thermal power unit equipment and extend the useful life of the thermal power unit equipment.

To achieve the above objectives, a thermal power generation unit frequency modulation system provided by an embodiment of the second aspect of the present invention comprises a thermal power grid interconnection unit, a standby transformer standby energy storage unit and a high voltage station transformer normal energy. a storage unit, wherein the thermal power generation unit frequency modulation system obtains a frequency modulation command for the thermal power grid interconnection unit, and if the power signal corresponding to the obtained frequency modulation command is less than a first power threshold, the said high voltage station transformer conventional energy storage unit to release energy to said thermal power grid connection unit or absorb energy released from said thermal power grid connection unit in response to a frequency modulation command; and supplying energy to the thermal power grid interconnection unit in response to the frequency modulation command if the power signal corresponding to the frequency modulation command is greater than a second power threshold that is greater than or equal to the first power threshold. controlling said high voltage station transformer normal energy storage unit and standby transformer standby energy storage unit to release or absorb energy released from said thermal power grid interconnection unit.

Optionally, in one embodiment of the present invention, said frequency modulation command comprises a frequency up command and a frequency down command, said thermal power unit frequency modulation system, in response to said frequency modulation command, said thermal power system When controlling said high voltage station transformer normal energy storage unit and standby transformer standby energy storage unit to release energy to the interconnection unit or absorb energy released from said thermal power grid interconnection unit; controlling the high voltage station transformer normal energy storage unit and the standby transformer standby energy storage unit to release energy to the thermal power grid interconnection unit when the frequency modulation command is the frequency up command; when the frequency modulation command is the frequency reduction command, controlling the high voltage station transformer normal energy storage unit and the standby transformer standby energy storage unit to absorb the energy released from the thermal power grid interconnection unit; do.

As described above, the thermal power generation unit frequency modulation system provided by the embodiment of the second aspect of the present invention acquires a frequency modulation command for the thermal power generation system interconnection unit, and the power signal corresponding to the acquired frequency modulation command is when less than a first power threshold, in response to the frequency modulation command, release energy to the thermal power grid connection unit or absorb energy released from the thermal power grid connection unit; controlling the high voltage station transformer normal energy storage unit, and in response to the frequency modulation command, if the power signal corresponding to the frequency modulation command is greater than a second power threshold greater than or equal to the first power threshold, the said high voltage station transformer normal energy storage unit and standby transformer standby energy storage unit to release energy to a thermal power grid interconnection unit or to absorb energy released from said thermal power grid interconnection unit; Control. Accordingly, the present invention implements power grid scheduling instructions by controlling the high voltage station transformer normal energy storage unit and the standby transformer standby energy storage unit to perform operations corresponding to power signals corresponding to frequency modulation instructions. It can accurately track and mitigate phenomena such as adjustment delay, adjustment deviation and adjustment reversal.

To achieve the above object, the thermal power generation unit frequency modulation device proposed in the third aspect of the present invention comprises a command acquisition module for acquiring a frequency modulation command for a thermal power grid interconnection unit, and the frequency modulation command releasing energy to the thermal power grid-connected unit or energy released from the thermal power grid-connected unit in response to the frequency modulation command, if the power signal corresponding to is less than a first power threshold and a second power threshold, wherein the power signal corresponding to the frequency modulation command is greater than or equal to the first power threshold. if greater, the high voltage station transformer to release energy to the thermal power grid connection unit or absorb energy released from the thermal power grid connection unit in response to the frequency modulation command. a high power frequency modulation module for controlling the transformer normal energy storage unit and the standby transformer standby energy storage unit.

Optionally, in one embodiment of the present invention, said frequency modulation command comprises a frequency up command and a frequency down command, said high power frequency modulation module, in response to said frequency modulation command, said thermal power system connection When controlling said high voltage station transformer normal energy storage unit and standby transformer standby energy storage unit to release energy to a grid unit or absorb energy released from said thermal power grid interconnection unit, controlling the high voltage station transformer normal energy storage unit and the standby transformer standby energy storage unit to release energy to the thermal power grid interconnection unit if the frequency modulation instruction is the frequency upgrade instruction; if the frequency modulation instruction is the frequency reduction instruction, controlling the high voltage station transformer normal energy storage unit and the standby transformer standby energy storage unit to absorb the energy released from the thermal power grid interconnection unit; .

From the above, the thermal power generation unit frequency modulation device provided by the embodiment of the third aspect of the present invention acquires the frequency modulation command for the thermal power grid interconnection unit by the command acquisition module, and the low power frequency modulation module: releasing energy to or from the thermal power grid connection unit in response to the frequency modulation command if the power signal corresponding to the frequency modulation command is less than a first power threshold; controlling the high voltage station transformer normal energy storage unit to absorb the released energy, and by a high power frequency modulation module, the power signal corresponding to the frequency modulation command is greater than or equal to the first power threshold; 2 power threshold, in response to said frequency modulation command, said It controls the high voltage station transformer normal energy storage unit and the standby transformer standby energy storage unit. The present invention accurately tracks power grid scheduling instructions by controlling the high voltage station transformer normal energy storage unit and the standby transformer standby energy storage unit to perform operations corresponding to power signals corresponding to frequency modulation instructions. This can reduce phenomena such as adjustment delay, adjustment deviation and adjustment reversal.

Additional aspects and advantages of the invention will be set forth in part and in part will be apparent from the following description, or may be learned by practice of the invention.

The above and/or additional aspects and advantages of the present invention will become clearer and easier to understand from the following description of embodiments with reference to the drawings.
1 is a schematic structural diagram of a thermal power unit frequency modulation system provided by an embodiment of the present invention; FIG. 1 is a schematic configuration diagram of a thermal power grid interconnection unit provided by an embodiment of the present invention; FIG. 1 is a schematic structural diagram of a pre-transformer standby energy storage unit provided by an embodiment of the present invention; FIG. 1 is a schematic structural diagram of a high voltage station transformer normal energy storage unit provided by an embodiment of the present invention; FIG. 1 is a schematic diagram of a PET provided by an embodiment of the present invention; FIG. 4 is a flow chart of the operation of the thermal power unit frequency modulation system provided by an embodiment of the present invention; 1 is a schematic structural diagram of a thermal power unit frequency modulation device provided by an embodiment of the present invention; FIG.

Hereinafter, embodiments of the present invention will be described in detail. Examples of embodiments are illustrated in the drawings, where the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functionality. The embodiments described below with reference to the drawings are exemplary and are only for the purpose of explaining the present invention and should not be understood as limiting the present invention. Rather, embodiments of the present invention include all changes, modifications and equivalents falling within the spirit and connotation of the appended utility model claims.

Hereinafter, the present invention will be described in detail according to specific examples.

FIG. 1 is a schematic structural diagram of a thermal power unit frequency modulation system provided by an embodiment of the present invention.

As shown in FIG. 1, the thermal power unit frequency modulation system provided by the embodiment of the present invention comprises a thermal power grid connection unit 1, a standby transformer standby energy storage unit 2 and a high voltage station transformer normal energy storage unit 3. Prepare.
The thermal power generation system interconnection unit 1 has a power grid transmission bus 1-3 and a generator 1-1 feeding the power grid transmission bus 1-3.
The standby transformer standby energy storage unit 2 comprises a thermal power unit standby transformer 2-1 and a standby energy storage device 2-8.
The high voltage station transformer conventional energy storage unit 3 has a conventional energy storage device 3-12. Here, the thermal power generation system interconnection unit 1 controls the active power output by the generator 1-1 based on the frequency modulation command. The pretransformer reserve energy storage unit 2 responds to frequency modulation commands by controlling the operational state of the reserve energy storage devices 2-8. Here, the high voltage side of the thermal power unit preliminary transformer 2-1 is connected to the power grid transmission bus 1-3, the low voltage side A branch of the thermal power unit preliminary transformer 2-1 is connected to the generator 1-1, and the high voltage The high voltage side of the station transformer conventional energy storage unit 3 is connected to the generator 1-1 and responds to frequency modulation commands by controlling the operating state of the conventional energy storage device 3-12.

According to some embodiments, the frequency modulation command is a command for indicating load changes, ie real power output changes of the generator 1-1.

In some embodiments, the pre-transformer standby energy storage unit 2 controls the operating state of the standby energy storage devices 2-8 to provide a standby power source to release or absorb power when responsive to frequency modulation commands. Controlling energy storage device 2-8 responds to frequency modulation commands in response to changes in the active power output of generator 1-1.

In some embodiments, the high voltage station transformer conventional energy storage unit 3 controls the operating state of the conventional energy storage devices 3-12 to normally release or absorb power when responsive to frequency modulation commands. Controlling the energy storage device 3-12 responds to frequency modulation commands in response to changes in the active power output of the generator 1-1.

In an embodiment of the present invention, FIG. 2 is a schematic configuration diagram of a thermal power system interconnection unit provided by an embodiment of the present invention. As shown in FIG. 2, the thermal power generation system interconnection unit 1 further has a generator main transformer 1-2. Here, the outlet of the generator 1-1 is connected to the low voltage side of the generator main transformer 1-2, and the high voltage side of the generator main transformer 1-2 is connected to the power grid transmission bus 1-3.

According to some embodiments, the voltage level of the power grid transmission bus 1-3 may be 220 kV. At this time, the generator main transformer 1-2 can boost the electrical energy output from the generator 1-1 from 20 kV to 220 kV.

In an embodiment of the present invention, FIG. 3 is a schematic structural diagram of a pre-transformer standby energy storage unit provided by an embodiment of the present invention. As shown in FIG. 3, the standby transformer standby energy storage unit 2 includes a standby transformer low voltage side A branch bus 2-2, a standby transformer low voltage side B branch bus 2-3, and a standby transformer low voltage side A branch circuit breaker. 2-4, a standby energy storage step-up transformer 2-5, a standby energy storage grid interconnection breaker 2-6 and a standby energy storage converter 2-7. Here, the low-voltage side of the thermal power unit standby transformer 2-1 is connected to the standby transformer low-voltage side A branch bus 2-2 and the standby transformer low-voltage side B branch bus 2-3. The bus 2-2 is connected to the outlet of the generator 1-1 by a standby transformer low voltage side A branch circuit breaker 2-4, and the standby transformer low voltage side B branch bus 2-3 is connected to a standby energy storage step-up transformer 2-5. , the standby energy storage step-up transformer 2-5 is connected to the AC side of the standby energy storage converter 2-7 by the standby energy storage system interconnection breaker 2-6, and the DC side of the standby energy storage converter 2-7. is connected to a reserve energy storage device 2-8.

According to some embodiments, the thermal power unit standby transformer 2-1 can provide on-site electrical energy to the thermal power plant when the power plant is out of service for inspection.

In an embodiment of the present invention, FIG. 4 is a schematic structural diagram of a normal energy storage unit of a high voltage station transformer provided by an embodiment of the present invention. As shown in FIG. 4, the high voltage station transformer normal energy storage unit 3 includes a split winding high voltage station transformer 3-1, a 6 kV station A branch 3-2, a 6 kV station B branch 3-3, a 6 kV station A branch breaker device 3-4, 6 kV on-site A branch load 3-5, 6 kV on-site B branch circuit breaker 3-6, 6 kV on-site B branch load 3-7, normal energy storage PET grid interconnection circuit breaker 3-8, PET 3-9, It has a normal energy storage PET low side circuit breaker 3-10 and a normal energy storage converter 3-11. Here, the high voltage side of the split winding high voltage station transformer 3-1 is connected to the outlet of the generator 1-1, and the low voltage side of the split winding high voltage station transformer 3-1 is connected to the 6 kV in-station A branch 3-2 and 6 kV station B branch 3-3, 6 kV station A branch 3-2 is connected to 6 kV station A branch load 3-5 by 6 kV station A branch circuit breaker 3-4, 6 kV station B branch 3-3 is 6 kV It is connected to the 6 kV on-site B branch load 3-7 by the on-site B branch circuit breaker 3-6, and the high voltage side of the PET 3-9 is normally connected to the 6 kV on-site B branch 3-3 by the energy storage PET grid interconnection circuit breaker 3-8. The low voltage side of the PET 3-9 is connected to the AC side of the normal energy storage converter 3-11 by the normal energy storage PET low voltage side circuit breaker 3-10, and the DC side of the normal energy storage converter 3-11 is connected to the normal energy storage device. 3-12.

According to some embodiments, the pre-transformer standby energy storage unit 2 and the high voltage station transformer normal energy storage unit 3 can be combined into one mixed energy storage system, and the mixed energy storage system is a thermal power system. Grid-connected unit 1 can be assisted to participate in grid frequency coordination. In addition, the rapid charge/discharge capabilities of the reserve energy storage device 2-8 and the normal energy storage device 3-12 are utilized to respond to changes in the grid load, whether with primary frequency modulation or secondary frequency modulation. or multi-order frequency modulation can assist the thermal power grid interconnection unit 1 to perform optimal power matching. This can improve the frequency modulation profit of the thermal power plant, can also reduce the output fluctuation of the generator 1-1, can improve the safety of the thermal power unit, and the frequent adjustment of the load It is possible to reduce the aging of thermal power generation unit facilities due to

In some embodiments, the standby energy storage device 2-8 includes a standby energy storage converter 2-7, a standby energy storage grid tie breaker 2-6, a standby energy storage step-up transformer 2-5, and a standby transformer low side. It is connected to a thermal power unit standby transformer 2-1 by a B-branch bus 2-3, and a normal energy storage device 3-12 includes a normal energy storage converter 3-11, a normal energy storage PET low-voltage side circuit breaker 3-10, and a PET 3- 9. The normal energy storage PET grid interconnection circuit breaker 3-8 and the 6 kV substation B branch 3-3 are connected to the split winding high voltage substation transformer 3-1, the standby energy storage device 2-8 and the normal energy storage device 3 -12 are connected to different transformers. Therefore, the load factor of the split winding high voltage station transformer 3-1 can be reduced, it is possible to ensure that the split winding high voltage station transformer 3-1 can be operated with a margin, and the load of the transformer can be effectively reduced. It is not necessary to increase the capacities of the split winding high voltage station transformer 3-1 and the thermal power unit standby transformer 2-1.

According to some embodiments, PET has the functionality of, but is limited to, conventional power frequency AC transformers, realized by power electronics technology and high frequency transformers (higher operating frequency than power frequency transformers). Refers to novel power electronic equipment that is not Compared with conventional commercial frequency transformers, the cost is lower, and PET is suitable for applications in aspects such as enriching system functions and enhancing system performance. The present invention uses PET to improve the normal energy storage and power supply efficiency of the high voltage station transformer normal energy storage unit 3, and reduce the construction cost of the energy storage system of the high voltage station transformer normal energy storage unit 3. be able to. In addition, the present invention uses PET to adjust the frequency of the response unit, the power change is faster and more accurate than the conventional commercial frequency transformer.

According to some embodiments, mixed energy storage technology is one of the key technology underpinnings of the energy transformation, as a large-scale energy storage technology that can be applied to power grids with many supporting services such as peak regulation, frequency modulation, and emergency response. In recent years, it has attracted wide attention within the industry because it can provide

In some embodiments, the pre-transformer standby energy storage unit 2 and the high voltage station transformer normal energy storage unit 3 provided by the embodiments of the present invention are mixed energy storage, which is a combination of flywheel energy storage + lithium battery. system, each with a reserve energy storage device 2-8 and a normal energy storage device 3-12 connected by a converter to a thermal power generation unit and provided with power bi-directional flow capability. In addition, there are advantages such as quick power adjustment and various application patterns.

In an embodiment of the present invention, FIG. 5 is a schematic structural diagram of PET provided by an embodiment of the present invention. As shown in FIG. 5, the PET 3-9 includes a normal energy storage PET high voltage DC-AC converter 3-9-1, a normal energy storage PET high voltage side filter capacitor 3-9-2, a normal energy storage PET high frequency DC-DC transformer 3-9-3, a normal energy storage PET low voltage side filter capacitor 3-9-4, and a normal energy storage PET low voltage AC-DC converter 3-9-5. Here, the AC side of the normal energy storage PET high voltage DC-AC converter 3-9-1 is connected to the normal energy storage PET grid interconnection circuit breaker 3-8, and the normal energy storage PET high frequency DC-DC transformer 3-9. -3 is connected to the DC side of a normal energy storage PET high voltage DC-to-AC converter 3-9-1 by a normal energy storage PET high voltage side filter capacitor 3-9-2, and the normal energy storage PET low voltage AC-to-DC converter The DC side of 3-9-5 is connected to the low side of a normal energy storage PET high frequency DC-DC transformer 3-9-3 by a normal energy storage PET low voltage side filter capacitor 3-9-4, and the normal energy storage PET low voltage The AC side of the AC to DC converter 3-9-5 is normally connected to an energy storage PET low side circuit breaker 3-10.

According to some embodiments, a conventional energy storage PET high voltage DC-AC converter 3-9-1, a conventional energy storage PET high voltage side filter capacitor 3-9-2, a conventional energy storage PET high frequency DC-DC transformer 3-9 -3, PET 3-9, which consists of normal energy storage PET low voltage side filter capacitor 3-9-4 and normal energy storage PET low voltage AC-DC converter 3-9-5, has a high frequency electromagnetic By using coupling technology, in realizing voltage level conversion, isolation and other functions of conventional transformers, it is possible to flexibly transform and effectively reduce the occupied area and volume of transformers.

According to some embodiments, when controlling the energy storage converters, namely the reserve energy storage converter 2-7 and the normal energy storage converter 3-11, the method of droop control is used to achieve effective and ineffective decoupling control. can do.

In some embodiments, when the method of droop control is used to achieve effective and ineffective decoupling control, the droop control for effective-angular frequency and reactive-voltage is realized according to the following formulas: can be done.

where ω is the output voltage angular frequency of the energy storage converter, U is the output voltage amplitude of the energy storage converter, ω ₀ is the no-load output voltage angular frequency reference of the energy storage converter, and U ₀ is the energy is the no-load output voltage swing reference value of the storage converter, m is the active power droop factor, n is the reactive power droop factor, P is the active power delivered to the load connected to the energy storage converter, Q is the reactive power delivered to the loads connected to the energy storage converter.

In an embodiment of the present invention, the PET is constructed with Modular Multilevel Converter (MMC) power electronics.

According to some embodiments, MMC power electronic components refer to power electronic components composed of cascaded at least two sub-modules with the same structure. The sub-module structure includes, but is not limited to, half H-bridge type, full H-bridge type and double-clamped sub-module type. MMC power electronics have low output harmonics, high electrical energy conversion efficiency, and high scalability. The voltage conversion of the MMC power electronic component is controllable, which can effectively suppress the short-circuit current caused by the ground fault, and reduce the situation of expanding the fault range when the fault occurs.

Thus, the thermal power unit frequency modulation system provided by the embodiment of the present invention comprises a thermal power grid interconnection unit, a standby transformer standby energy storage unit and a high voltage station transformer normal energy storage unit, and comprises: The interconnection unit has a power grid transmission bus and a generator feeding the power grid transmission bus, the standby transformer standby energy storage unit has a thermal power unit standby transformer and a standby energy storage device, and the high voltage station transformer usually An energy storage unit usually has an energy storage device. wherein the thermal power grid interconnection unit controls the active power output by the generator according to the frequency modulation command, and the standby transformer standby energy storage unit controls the working state of the standby energy storage device; in response to frequency modulation instructions, wherein the high voltage side of the thermal power unit standby transformer is connected to the power grid transmission bus, the low voltage side A branch of the thermal power unit standby transformer is connected to the generator, and the high voltage station transformer The high voltage side of the energy storage unit is typically connected to a generator and typically responds to frequency modulation commands by controlling the operating state of the energy storage device. The present invention uses a standby transformer standby energy storage unit to control the operating state of the standby energy storage device to respond to frequency modulation commands, and a high voltage station transformer normal energy storage unit to control the normal energy storage device. By controlling the operating state of the thermal power unit frequency modulation system to respond to the frequency modulation command, the response speed of the thermal power unit frequency modulation system in performing frequency modulation tasks and the ramp rate of the unit can be improved. The present invention can also reduce the number of times of power conversion and operation. This can reduce the degree of fatigue and wear of the thermal power unit equipment and extend the service life of the thermal power unit equipment.

To implement the above embodiments, the present invention further provides a thermal power unit frequency modulation system.

FIG. 6 is a flow chart of the operation of the thermal power unit frequency modulation system provided by an embodiment of the present invention.

As shown in FIG. 6, the thermal power unit frequency modulation system comprises a thermal power grid interconnection unit, a standby transformer standby energy storage unit and a high voltage station transformer normal energy storage unit, and the thermal power unit frequency modulation system comprises a thermal power step S101 of obtaining a frequency modulation command for the power grid interconnection unit 1; step S102 of controlling the high voltage station transformer normal energy storage unit 3 to release energy or absorb the energy released from the thermal power grid interconnection unit 1; , a second power threshold that is greater than or equal to the first power threshold, the energy is released to the thermal power grid-connected unit 1 or released from the thermal power grid-connected unit 1 in response to the frequency modulation command and a step S103 of controlling the high voltage station transformer normal energy storage unit 3 and the standby transformer standby energy storage unit 2 to absorb energy.

According to some embodiments, the standby transformer standby energy storage unit 2 comprises a standby energy storage device 2-8 and a thermal power unit standby transformer 2-1. The high voltage station transformer conventional energy storage unit 3 typically has an energy storage device 3-12. The thermal power unit frequency modulation system releases energy to the thermal power grid-connected unit 1 or absorbs the energy released from the thermal power grid-connected unit 1 in response to the frequency modulation command. When controlling the primary energy storage unit 3 and the standby transformer standby energy storage unit 2, the thermal power unit frequency modulation system controls the standby energy storage device 2-8 to connect to the thermal power unit standby transformer 2-1. be able to. Thereby, the thermal power unit frequency modulation system controls the reserve energy storage device 2-8 and the normal energy storage device 3-12 to absorb energy together or release energy together. It can respond to frequency changes corresponding to frequency modulation commands.

In an embodiment of the present invention, the frequency modulation command includes a frequency up command and a frequency down command, and the thermal power unit frequency modulation system releases energy to the thermal power grid interconnection unit in response to the frequency modulation command. or if the high voltage station transformer normal energy storage unit and standby transformer standby energy storage unit are controlled to absorb the energy released from the thermal power grid connection unit, if the frequency modulation order is a frequency up order , controlling the high voltage station transformer normal energy storage unit and the standby transformer standby energy storage unit to release energy to the thermal power grid interconnection unit, and if the frequency modulation command is a frequency down command, the thermal power grid interconnection Control the high voltage station transformer normal energy storage unit and the standby transformer standby energy storage unit to absorb the energy released from the unit.

According to some embodiments, the frequency up command, also called load up command, refers to the command to direct the frequency up of the thermal power grid interconnection unit 1 . If the frequency modulation command is a frequency up command, the thermal power unit frequency modulation system can control the reserve energy storage device 2-8 and the normal energy storage device 3-12 to release electrical energy.

According to some embodiments, the frequency down command is also called load down command and refers to the command to direct the frequency down of the thermal power grid interconnection unit 1 . If the frequency modulation command is a frequency down command, the thermal power unit frequency modulation system can control the reserve energy storage device 2-8 and the normal energy storage device 3-12 to absorb electrical energy.

From the above, the thermal power unit frequency modulation system provided by the embodiment of the present invention obtains the frequency modulation command for the thermal power grid interconnection unit, and if the power signal corresponding to the frequency modulation command is less than the first power threshold , in response to the frequency modulation command, control the high voltage station transformer normally energy storage unit to release energy to the thermal power grid connection unit or to absorb the energy released from the thermal power grid connection unit. , the power signal corresponding to the frequency modulation command is greater than a second power threshold that is greater than or equal to the first power threshold, in response to the frequency modulation command, releasing energy to the thermal power grid interconnection unit or thermal power generation The high voltage station transformer normal energy storage unit and the standby transformer standby energy storage unit are controlled to absorb the energy released from the grid connection unit. Accordingly, the present invention implements power grid scheduling instructions by controlling the high voltage station transformer normal energy storage unit and the standby transformer standby energy storage unit to perform operations corresponding to power signals corresponding to frequency modulation instructions. It can accurately track and mitigate phenomena such as adjustment delay, adjustment deviation and adjustment reversal.

In order to implement the above embodiments, the present invention further provides a thermal power unit frequency modulation device.

FIG. 7 is a schematic structural diagram of a thermal power unit frequency modulation device provided by an embodiment of the present invention.

As shown in FIG. 7, a thermal power unit frequency modulation device 700 includes a command acquisition module 701 for acquiring a frequency modulation command for a thermal power grid-connected unit, and a power signal corresponding to the frequency modulation command at a first power threshold value. If less, the high voltage substation transformer normally stores energy so as to release energy to the thermal power grid connection unit or absorb energy released from the thermal power grid connection unit in response to the frequency modulation command. a low power frequency modulation module 702 for controlling a unit and a thermal power system in response to a frequency modulation command when the power signal corresponding to the frequency modulation command is greater than a second power threshold greater than or equal to the first power threshold; High power transformers for controlling the high voltage station transformer normal energy storage unit and the standby transformer standby energy storage unit to release energy to the interconnection unit or absorb energy released from the thermal power grid interconnection unit. and a power frequency modulation module 703 .

In an embodiment of the present invention, the frequency modulation command includes a frequency up command and a frequency down command, and the high power frequency modulation module 703 releases energy to the thermal power grid interconnection unit in response to the frequency modulation command. or if the high voltage station transformer normal energy storage unit and standby transformer standby energy storage unit are controlled to absorb the energy released from the thermal power grid connection unit, if the frequency modulation order is a frequency up order , controlling the high voltage station transformer normal energy storage unit and the standby transformer standby energy storage unit to release energy to the thermal power grid interconnection unit, and if the frequency modulation command is a frequency up command, the thermal power grid interconnection Control the high voltage station transformer normal energy storage unit and the standby transformer standby energy storage unit to absorb the energy released from the unit.

Thus, in the thermal power unit frequency modulation device provided by the embodiment of the present invention, the command acquisition module acquires the frequency modulation command for the thermal power grid interconnection unit, and the low power frequency modulation module responds to the frequency modulation command. to release energy to the thermal power grid-connected unit or absorb energy released from the thermal power grid-connected unit in response to the frequency modulation command if the power signal applied is less than the first power threshold; , a high voltage station transformer normal energy storage unit, and a high power frequency modulation module responds to the frequency modulation command if the power signal corresponding to the frequency modulation command is greater than a second power threshold greater than or equal to the first power threshold. and the high voltage station transformer normal energy storage unit and standby transformer standby energy storage unit so as to release energy to the thermal power grid connection unit or absorb the energy released from the thermal power grid connection unit to control. Accordingly, the present invention implements power grid scheduling instructions by controlling the high voltage station transformer normal energy storage unit and the standby transformer standby energy storage unit to perform operations corresponding to power signals corresponding to frequency modulation instructions. It can accurately track and mitigate phenomena such as adjustment delay, adjustment deviation and adjustment reversal.

It should be noted that, in describing the present invention, the terms "first", "second", etc. are used for descriptive purposes and should not be construed as indicating or implying relative importance. Also, in the description of the present invention, the term "plurality" means two or more, unless stated otherwise.

Any process or method description illustrated in a flow chart or otherwise herein may be viewed as a module, fragment or portion representing code of instructions executable by one or more steps for performing a particular logical function or process. and the scope of preferred embodiments of the invention includes other implementations, not according to the order shown or discussed herein, but essentially concurrently, depending on the functionality involved. Including performing functions in order or in reverse order, this should be understood by those skilled in the art.

It should be understood that portions of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, steps or methods may be implemented by software or firmware storable in memory and executed on a suitable instruction execution system. For example, when implemented in hardware, a discrete logic circuit with logic gate circuitry for performing logic functions on data signals, a dedicated integrated circuit with appropriate combinatorial logic gate circuitry, as in the other embodiments. , Programmable Gate Array (PGA), Field Programmable Gate Array (FPGA), etc., any one or combination of the following technologies in the art.

Those skilled in the art will understand that all or part of the steps included in the above-described embodiment methods can be completed by instructing the relevant hardware with a program, and the program can be stored in a computer-readable storage medium. , may be understood to include any one or combination of the steps of the method embodiments when the program is executed.

Also, each functional unit in each embodiment of the present invention may be integrated into one processing module, each unit may physically exist alone, and two or more units may be integrated into one module. may The integrated modules can be implemented in the form of hardware or in the form of software functional modules. The integrated modules, when implemented in the form of software functional modules and sold or used as stand-alone products, can also be stored in computer-readable storage media.

The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, or the like.

In the present description, descriptions of reference terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples" refer to the embodiment or Refers to inclusion of a particular feature, structure, material or feature described for an example in at least one embodiment or example of the present invention. In this specification, exemplary statements for such terms do not necessarily refer to the same embodiment or example. And the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although embodiments of the present invention have been shown and described above, the above embodiments are illustrative and should not be construed as limitations on the invention, and those skilled in the art will be able to make modifications within the scope of the invention. Changes, modifications, alterations and variations can be made to the embodiments described above.

1 Thermal power grid interconnection unit 2 Standby transformer standby energy storage unit 3 High voltage station transformer normal energy storage unit 1-1 Generator 1-2 Generator main transformer 1-3 Power grid transmission bus 2-1 Thermal power unit standby Transformer 2-2 Standby transformer low voltage side A branch bus 2-3 Standby transformer low voltage side B branch bus 2-4 Standby transformer low voltage side A branch circuit breaker 2-5 Standby energy storage step-up transformer 2-6 Standby energy Storage grid interconnection breaker 2-7 Standby energy storage converter 2-8 Standby energy storage device 3-1 Split winding high voltage station transformer 3-2 6 kV in-station A branch 3-3 6 kV in-station B branch 3-4 6 kV in-station A Branch circuit breaker 3-5 6 kV in-station A branch load 3-6 6 kV in-station B branch circuit breaker 3-7 6 kV in-station B branch load 3-8 Normal energy storage PET system interconnection circuit breaker 3-9 PET
3-10 Normal energy storage PET low voltage side circuit breaker 3-11 Normal energy storage converter 3-12 Normal energy storage device 3-9-1 Normal energy storage PET high voltage DC-AC converter 3-9-2 Normal energy storage PET high voltage side Filter Capacitor 3-9-3 Normal Energy Storage PET High Frequency DC-DC Transformer 3-9-4 Normal Energy Storage PET Low Side Filter Capacitor 3-9-5 Normal Energy Storage PET Low Voltage AC-DC Converter 700 Thermal Power Unit Frequency Modulation Device 701 Instruction Acquisition Module 702 Low Power Frequency Modulation Module 703 High Power Frequency Modulation Module

Claims (10)

A thermal power unit frequency modulation system comprising:
comprising a thermal power grid interconnection unit, a standby transformer standby energy storage unit, and a high voltage station transformer normal energy storage unit,
The thermal power grid interconnection unit has a power grid transmission bus and a generator feeding the power grid transmission bus,
the standby transformer standby energy storage unit comprises a thermal power unit standby transformer and a standby energy storage device;
The high voltage station transformer conventional energy storage unit typically comprises an energy storage device,
The thermal power grid interconnection unit controls the active power output by the generator based on the frequency modulation command,
the standby transformer standby energy storage unit responds to the frequency modulation command by controlling the operating state of the standby energy storage device, wherein the high voltage side of the thermal power unit standby transformer is connected to the power grid transmission bus; A low-voltage side A branch of the thermal power unit standby transformer is connected to the generator,
The high voltage side of the high voltage station transformer conventional energy storage unit is connected to the generator and responds to the frequency modulation command by controlling the operating state of the conventional energy storage device. Unit frequency modulation system. The thermal power grid interconnection unit further has a generator main transformer,
2. The thermal power plant of claim 1, wherein the outlet of the generator is connected to the low voltage side of the generator main transformer and the high voltage side of the generator main transformer is connected to the power grid transmission bus. Power generation unit frequency modulation system. The standby transformer standby energy storage unit includes a standby transformer low voltage side A branch bus, a standby transformer low voltage side B branch bus, a standby transformer low voltage side A branch circuit breaker, a standby energy storage step-up transformer, and a standby energy storage system. further comprising a system breaker and a reserve energy storage converter;
The low voltage side of the thermal power unit standby transformer is connected to the standby transformer low voltage side A branch bus and the standby transformer low voltage side B branch bus, and the standby transformer low voltage side A branch bus is connected to the standby transformer low voltage side. connected to the outlet of the generator by an A-branch circuit breaker, the standby transformer low-voltage side B-branch bus is connected to the standby energy storage step-up transformer, and the standby energy storage step-up transformer is connected to the standby energy storage grid connection; The thermal power unit frequency modulation according to claim 1, characterized in that a circuit breaker is connected to the AC side of the reserve energy storage converter, and the DC side of the reserve energy storage converter is connected to the reserve energy storage device. system. The high voltage station transformer normal energy storage unit includes: split winding high voltage station transformer, 6 kV station A branch, 6 kV station B branch, 6 kV station A branch circuit breaker, 6 kV station A branch load, 6 kV station B branch circuit breaker, 6 kV having a station B branch load, a conventional energy storage PET grid tie breaker, a PET, a conventional energy storage PET low side circuit breaker, and a conventional energy storage converter;
The high voltage side of the split winding high voltage station transformer is connected to the outlet of the generator, the low voltage side of the split winding high voltage station transformer is connected to the 6 kV in-station A branch and the 6 kV in-station B branch, and the 6 kV The in-station A branch is connected to the 6 kV in-station A branch load by the 6 kV in-station A branch circuit breaker, the 6 kV in-station B branch is connected to the 6 kV in-station B branch load by the 6 kV in-station B branch circuit breaker, and the high voltage of the PET side is connected to the 6 kV on-site B branch by the conventional energy storage PET grid interconnection circuit breaker, the low voltage side of the PET is connected to the AC side of the conventional energy storage converter by the conventional energy storage PET low voltage side circuit breaker, 2. The thermal power unit frequency modulation system of claim 1, wherein the DC side of the conventional energy storage converter is connected to the conventional energy storage device. The PET includes a normal energy storage PET high voltage DC-AC converter, a normal energy storage PET high side filter capacitor, a normal energy storage PET high frequency DC-DC transformer, a normal energy storage PET low side filter capacitor, and a normal energy storage PET low voltage AC. - having a DC converter,
The AC side of the conventional energy storage PET high voltage DC-AC converter is connected to the conventional energy storage PET grid interconnection circuit breaker, and the high voltage side of the conventional energy storage PET high frequency DC-DC transformer is the normal energy storage PET high voltage side. The DC side of the conventional energy storage PET high voltage DC-AC converter is connected by a filter capacitor, and the DC side of the conventional energy storage PET low voltage AC-DC converter is connected to the conventional energy storage PET high voltage by the conventional energy storage PET low voltage side filter capacitor. 5. The conventional energy storage PET low voltage circuit breaker connected to the low voltage side of a DC-DC transformer, wherein the AC side of the conventional energy storage PET low voltage AC-DC converter is connected to the conventional energy storage PET low voltage side circuit breaker. thermal power unit frequency modulation system. 5. The thermal power unit frequency modulation system according to claim 4, wherein said PET is composed of modular multi-level converter MMC power electronics. A thermal power unit frequency modulation system comprising:
Equipped with a thermal power grid interconnection unit, a standby transformer standby energy storage unit and a high voltage station transformer normal energy storage unit,
The thermal power unit frequency modulation system comprises:
obtaining a frequency modulation command for the thermal power grid interconnection unit;
releasing energy to the thermal power grid connection unit or controlling the thermal power grid connection in response to the frequency modulation command if the obtained power signal corresponding to the frequency modulation command is less than a first power threshold; controlling said high voltage station transformer normal energy storage unit to absorb energy released from the unit;
releasing energy to the thermal power grid interconnection unit in response to the frequency modulation command if a power signal corresponding to the frequency modulation command is greater than a second power threshold that is greater than or equal to the first power threshold; or controlling the high voltage station transformer normal energy storage unit and the standby transformer standby energy storage unit to absorb the energy released from the thermal power grid interconnection unit. modulation system. the frequency modulation command includes a frequency up command and a frequency down command;
The thermal power unit frequency modulation system comprises:
a high voltage station transformer conventional energy storage unit to release energy to the thermal power grid connection unit or absorb energy released from the thermal power grid connection unit in response to the frequency modulation command; and when controlling the standby transformer standby energy storage unit,
controlling the high voltage station transformer normal energy storage unit and the standby transformer standby energy storage unit to release energy to the thermal power grid interconnection unit if the frequency modulation instruction is the frequency upgrade instruction;
when the frequency modulation command is the frequency reduction command, controlling the high voltage station transformer normal energy storage unit and the standby transformer standby energy storage unit to absorb the energy released from the thermal power grid interconnection unit; 8. The thermal power unit frequency modulation system of claim 7, wherein: A thermal power unit frequency modulation device,
an instruction acquisition module for acquiring a frequency modulation instruction for a thermal power grid interconnection unit;
releasing energy to or from the thermal power grid connection unit in response to the frequency modulation command if the power signal corresponding to the frequency modulation command is less than a first power threshold; a low power frequency modulation module for controlling a high voltage station transformer conventional energy storage unit to absorb the released energy;
releasing energy to the thermal power grid interconnection unit in response to the frequency modulation command if a power signal corresponding to the frequency modulation command is greater than a second power threshold that is greater than or equal to the first power threshold; or a high power frequency modulation module for controlling the high voltage station transformer normal energy storage unit and the standby transformer standby energy storage unit to absorb the energy released from the thermal power grid connection unit. A thermal power generation unit frequency modulation device characterized by: the frequency modulation command includes a frequency up command and a frequency down command;
The high power frequency modulation module comprises:
a high voltage station transformer conventional energy storage unit to release energy to the thermal power grid connection unit or absorb energy released from the thermal power grid connection unit in response to the frequency modulation command; and when controlling the standby transformer standby energy storage unit,
controlling the high voltage station transformer normal energy storage unit and the standby transformer standby energy storage unit to release energy to the thermal power grid interconnection unit if the frequency modulation instruction is the frequency upgrade instruction;
when the frequency modulation command is the frequency reduction command, controlling the high voltage station transformer normal energy storage unit and the standby transformer standby energy storage unit to absorb the energy released from the thermal power grid interconnection unit; 10. The thermal power generation unit frequency modulation device according to claim 9, characterized by: