Thermal power plant black start system and method combining small-sized combustion engine with FCB function
Technical Field
The invention belongs to the technical field of black start of a thermal power plant, and relates to a black start system and a black start method of the thermal power plant, which are combined with a small-sized gas turbine with an FCB function.
Background
The black start refers to a process that after the power system is shut down due to a fault, the power system drives the power supply without the self-starting capability through the power supply with the self-starting capability in the starting system without the help of other networks, so that the power generation capability is recovered again, and the power system and the black start power supply are connected in parallel to form a small system. The aim is to realize the safe start of the shutdown unit in the shortest time and provide power support for the subsequent recovery of the system.
In recent years, whether the power grid has black start capability or not is gradually used as an important index for assessing whether the power grid is safe or not in China. The investment of the black start research work of the power grid is increased by each region and province company, a black start scheme which is suitable for the actual condition of the regional power grid is formulated, and black start tests are successively carried out and succeeded.
According to the black start power supply selection principle, a power plant which is high in access voltage level, close to an important load center and beneficial to quickly recovering other power supplies is preferentially considered as a black start power supply, and then a unit which is high in rated power, good in starting and adjusting performance and has the phase advance operation capacity is selected in the power plant. The hydroelectric generating set and the gas generating set are low in service load and high in starting speed, and can finish self-starting within 5-10 min, so that the hydroelectric generating set and the gas generating set become the first choice of a black-start power supply. However, due to the limitation of regional resource conditions, such as fewer hydropower stations in the northwest region, it is unlikely that a hydroelectric generating set is selected as a black start power supply. The new energy power station has limited power transmission capability due to low voltage of an access system, and the advantage of being used as a black start power supply is not obvious due to the fact that common stations are dispersed. The thermal generator set is generally large in capacity, high in access voltage level and capable of achieving certain phase advance, and is very suitable for serving as a black start power supply of northern areas lacking water resources, but the starting process flow is complex, the power of auxiliary equipment is large, the required plant power consumption is large, the requirement on the generator set with the self-starting capability is very high, the large diesel generator set is used as the self-starting power supply of a thermal power plant in parallel, on one hand, the investment is large, and the diesel generator set is idle when the generator set operates normally, so that resource waste is caused.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a black start system and a black start method for a thermal power plant combined with a small gas turbine with an FCB function, the system and the method solve the defect of lack of hydroelectric resources or large gas turbine units in northern areas, and the system has high safety.
In order to achieve the purpose, the thermal power plant black start system combined with the small-sized gas turbine with the FCB function comprises a coal-fired generator, a main transformer, a service transformer, auxiliary machinery for the service of the coal-fired generator and other loads, auxiliary machinery for the service of the gas turbine and other loads, a service incoming line circuit breaker, a service 6kV bus section, a gas turbine system, a security transformer, a security PC section bus, a security MCC section feeder circuit breaker, a security MCC section incoming line circuit breaker, a security MCC section bus, a diesel generator incoming line circuit breaker, a diesel generator, a synchronous device, a gas turbine TCS system and a spare power automatic switching device, wherein the gas turbine system comprises a gas turbine generator and a gas turbine generator outlet circuit breaker;
the machine end of the coal-fired generator is respectively connected with one side of a main transformer and one side of a service transformer, the other side of the main transformer is connected with a power grid system, and the other side of the service transformer is connected with a service 6kV bus section through a service incoming line breaker; the gas turbine generator is connected with the factory 6kV bus section through a gas turbine generator outlet circuit breaker, the factory auxiliary machine and other loads of the coal-fired unit are connected with the factory 6kV bus section, the factory auxiliary machine and other loads of the gas turbine are connected with the factory 6kV bus section, and the factory 6kV bus section is connected with a security PC section bus through a security transformer;
the security PC section bus is connected with the security MCC section bus through the security MCC section feeder circuit breaker and the security MCC section incoming line circuit breaker; the diesel generator is connected with a bus from power transmission to the security MCC section through a diesel generator incoming line breaker;
the synchronization device is connected with a service incoming line breaker and a service 6kV bus section; the gas turbine TCS system is connected with the gas turbine system; the spare power automatic switching device is connected with a security MCC section incoming line breaker and a diesel generator incoming line breaker.
The main transformer is connected with a power grid system through a main transformer high-voltage side circuit breaker.
The 6kV bus section for the plant is connected with the safety PC section bus through the safety PC section incoming line circuit breaker and the safety transformer.
The diesel generator is connected with a bus from power transmission to the security MCC section through a diesel generator outlet circuit breaker and a diesel generator inlet circuit breaker.
Auxiliary machines and other loads for the coal-fired plant factory are connected with a factory 6kV bus section through a factory load breaker of the coal-fired plant factory.
Auxiliary machines and other loads for the gas turbine plant are connected with a 6kV plant bus section through a load circuit breaker for the gas turbine plant.
The black start method of the thermal power plant combined with the small combustion engine with the FCB function comprises the following steps of:
1) when the unit normally operates, the coal-fired generator is connected to the grid for generating electricity, a main transformer high-voltage side circuit breaker is in a closed position, a plant incoming line circuit breaker is in a closed position, a plant load circuit breaker of the coal-fired unit is in a closed position, a plant load circuit breaker of the gas turbine is in a closed position, an outlet circuit breaker of the gas turbine generator is in a closed position, and a plant 6kV bus section is supplied with power by combining a plant transformer and the gas turbine generator;
2) the method comprises the following steps that a security PC section incoming line breaker is in a closed position, a security MCC section feeder line breaker is in a closed position, a security MCC section incoming line breaker is in a closed position, a diesel generator incoming line breaker is in a separated position, a diesel generator outlet breaker is in a separated position, and the voltages of a security PC section bus and a security MCC section bus are normal;
3) the spare power automatic switching device is normally switched on, and the diesel generator is in a cold standby state;
4) when the gas turbine system needs frequency modulation when the gas turbine system vibrates, the gas turbine TCS system adjusts the gas turbine system to send a frequency modulation instruction, and adjusts the output of the gas turbine generator to perform frequency modulation;
5) when the gas turbine system vibrates to cause the coal-fired unit to be disconnected, the zero-power generator-cutting machine of the coal-fired generator performs protection action to trip a main transformer high-voltage side circuit breaker and a service incoming line circuit breaker;
6) after the combustion engine TCS system receives the command of entering the FCB mode, the output of the combustion engine system is adjusted according to the auxiliary engine and other loads of the coal-fired plant and the loads of the auxiliary engine and other loads of the combustion engine plant;
7) after the gas turbine system enters the FCB mode, when the gas turbine generator can maintain stable operation of auxiliary machines and other loads for the coal-fired plant and auxiliary machines and other loads for the gas turbine plant, turning to the step 8), and otherwise, turning to the step 9);
8) after the gas turbine generator operates stably, restarting the coal-fired unit, after the coal-fired generator is restarted, closing a service incoming line circuit breaker and a main transformer high-voltage side circuit breaker by utilizing a synchronization device to charge a line, and using the gas turbine generator as a black start power supply;
9) tripping the gas turbine generator and tripping an outlet circuit breaker of the gas turbine generator, tripping a factory-used 6kV bus section, and tripping a factory-used load circuit breaker of the coal-fired unit and a factory-used load circuit breaker of the gas turbine;
10) the backup automatic switching device sends a command to the diesel generator to start voltage build-up, the backup automatic switching device automatically switches in a circuit breaker at the outlet of the diesel generator after the voltage build-up of the diesel generator is successful, the backup automatic switching device trips out a circuit breaker at the inlet of a security MCC section and switches in the circuit breaker at the inlet of the diesel generator, and a bus at the security MCC section is powered by the diesel generator;
11) the safety MCC section bus is switched into a safety MCC section incoming line breaker after no abnormity occurs, the safety PC section bus is powered by a diesel generator, the safety PC section bus is switched into the safety PC section incoming line breaker after no abnormity occurs, and the plant 6kV bus is powered by the diesel generator;
12) closing a load circuit breaker for a plant of the gas turbine, sequentially putting auxiliary machines and other loads for the plant of the gas turbine, starting a gas turbine generator, closing an outlet circuit breaker of the gas turbine generator after the pressure of the gas turbine generator is built, and supplying power to a 6kV bus section for the plant by the gas turbine generator;
13) disconnecting an inlet circuit breaker of the diesel generator and an outlet circuit breaker of the diesel generator, and withdrawing the diesel generator;
14) closing a load circuit breaker for a coal-fired unit plant, sequentially putting auxiliary machines and other loads for the coal-fired unit plant, starting a gas turbine generator, and closing a service incoming line circuit breaker by using a synchronous device after the pressure of the coal-fired generator is built;
15) and after the operating parameters of the coal-fired generator are not abnormal, the coal-fired generator is combined with a main high-voltage side circuit breaker to charge the line, and the coal-fired generator is used as a black start power supply.
The invention has the following beneficial effects:
the thermal power plant black start system and the method combining the small-sized gas turbine with the FCB function can reduce the plant service power rate of the thermal power plant during normal operation, when an external network power supply is lost, the coal-fired generator firstly enters the FCB self-sustaining plant service power and serves as the self-starting power supply of the thermal power plant to start the thermal power plant, when the unit trips due to failure of the FCB self-sustaining plant service power, the diesel generator set provides power to quickly recover to start the gas turbine, the plant service power system of the thermal power plant is recovered to start the thermal power plant, the investment cost is low, the construction period is short, the single machine power is high, the single machine power can be effectively utilized, the defect that water and power resources or large-sized gas turbine units are lacked in northern areas can be effectively overcome, and the system safety is greatly improved.
Drawings
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is a flow chart of the present invention.
The system comprises a coal-fired generator 1, a main transformer 2, a main transformer high-voltage side circuit breaker 3, a plant transformer 4, a coal-fired unit plant auxiliary machine and other loads 5, a gas-fired unit plant auxiliary machine and other loads 6, a gas-fired unit plant auxiliary machine and other loads 7, a plant incoming line circuit breaker 8, a coal-fired unit plant load circuit breaker 9, a gas-fired unit plant load circuit breaker 10, a plant 6kV bus section 10, a gas-fired generator 11, a security gas-fired generator PC section incoming line circuit breaker 12, a security gas-fired generator outlet circuit breaker 13, a security transformer 14, a security PC section bus 15, a security MCC section feeder circuit breaker 16, a security MCC section incoming line circuit breaker 17, a security MCC section bus 18, a security section MCC circuit breaker 19, a diesel generator incoming line circuit breaker 20, a diesel generator outlet circuit breaker 21, a diesel generator 22, a synchronous device 23, a gas-fired machine TCS system and a backup automatic switching device 24.
Detailed Description
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments, and are not intended to limit the scope of the present disclosure. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present disclosure. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
There is shown in the drawings a schematic block diagram of a disclosed embodiment in accordance with the invention. The figures are not drawn to scale, wherein certain details are exaggerated and possibly omitted for clarity of presentation. The shapes of various regions, layers and their relative sizes and positional relationships shown in the drawings are merely exemplary, and deviations may occur in practice due to manufacturing tolerances or technical limitations, and a person skilled in the art may additionally design regions/layers having different shapes, sizes, relative positions, according to actual needs.
Referring to fig. 1, the thermal power plant black start system of the small gas turbine with FCB function of the present invention comprises a coal-fired power generator 1, a main transformer 2, a main high-voltage side circuit breaker 3, a service transformer 4, auxiliary machinery and other loads 5 for the coal-fired power plant, auxiliary machinery and other loads 6 for the gas turbine plant, a service incoming line circuit breaker 7, a load circuit breaker 8 for the coal-fired power plant, a load circuit breaker 9 for the gas turbine plant, a service 6kV bus section 10, a gas turbine power generator 11, and a security PC section incoming line circuit breaker 12, the system comprises a gas turbine generator outlet circuit breaker 13, a security transformer 14, a security PC section bus 15, a security MCC section feeder circuit breaker 16, a security MCC section incoming line circuit breaker 17, a security MCC section bus 18, a diesel generator incoming line circuit breaker 19, a diesel generator outlet circuit breaker 20, a diesel generator 21, a synchronous device 22, a gas turbine TCS system 23 and a spare power automatic switching device 24;
the machine end of a coal-fired generator 1 is respectively connected with one side of a main transformer 2 and one side of a service transformer 4, the other side of the main transformer 2 is connected with a power grid system through a main transformer high-voltage side circuit breaker 3, and the other side of the service transformer 4 is connected with a service 6kV bus section 10 through a service incoming line circuit breaker 7;
the gas turbine generator 11 is connected with the plant 6kV bus section 10 through a gas turbine generator outlet circuit breaker 13, the auxiliary machine and other loads 5 for the coal-fired plant are connected with the plant 6kV bus section 10 through a plant load circuit breaker 8 for the coal-fired plant, and the auxiliary machine and other loads 6 for the gas turbine plant are connected with the plant 6kV bus section 10 through a plant load circuit breaker 9 for the gas turbine;
the plant 6kV bus section 10 is connected with a security PC section bus 15 through a security PC section incoming line breaker 12 and a security transformer 14;
the security PC section bus 15 is connected with the security MCC section bus 18 through a security MCC section feeder circuit breaker 16 and a security MCC section incoming line circuit breaker 17;
the diesel generator 21 is connected with a bus 18 from power transmission to a security MCC section through a diesel generator outlet circuit breaker 20 and a diesel generator inlet circuit breaker 19;
the synchronization device 22 is connected with the service incoming line breaker 7 and the service 6kV bus section 10;
the combustion engine TCS system 23 is connected with a combustion engine system, and the combustion engine system comprises a combustion engine generator 11 and a combustion engine generator outlet breaker 13;
the spare power automatic switching device 24 is connected with the security MCC section incoming line breaker 17 and the diesel generator incoming line breaker 19.
Referring to fig. 2, the black start method of the thermal power plant combined with the small combustion engine with FCB function according to the present invention comprises the following steps:
1) when the unit normally operates, the coal-fired generator 1 is used for grid-connected power generation, a main transformer high-voltage side circuit breaker 3 is in a closed position, a plant incoming line circuit breaker 7 is in a closed position, a plant load circuit breaker 8 of the coal-fired generator is in a closed position, a plant load circuit breaker 9 of the gas turbine is in a closed position, an outlet circuit breaker 13 of the gas turbine generator is in a closed position, and a plant 6kV bus section 10 is supplied with power by combining a plant transformer 4 and a gas turbine generator 11;
2) the method comprises the following steps that a security PC section incoming line breaker 12 is located at a closed position, a security MCC section feeder line breaker 16 is located at a closed position, a security MCC section incoming line breaker 17 is located at a closed position, a diesel generator incoming line breaker 19 is located at a separated position, a diesel generator outlet breaker 20 is located at a separated position, and voltages of a security PC section bus 15 and a security MCC section bus 18 are normal;
3) the spare power automatic switching device 24 is normally switched on, and the diesel generator 21 is in a cold standby state;
4) when the gas turbine system needs frequency modulation when the gas turbine system vibrates, the gas turbine TCS system 23 sends a frequency modulation instruction to the gas turbine system to adjust the output of the gas turbine generator 11 for frequency modulation;
5) when the gas turbine system vibrates to cause the coal-fired unit to be disconnected, the zero-power generator-cutting machine of the coal-fired generator 1 performs protection action to trip the main transformer high-voltage side circuit breaker 3 and the service incoming line circuit breaker 7;
6) the combustion engine TCS system 23 receives the command of entering the FCB mode, and then the output of the combustion engine system is adjusted according to the load of auxiliary machines and other loads 5 and 6 for the coal-fired plant factory;
7) after the gas turbine system enters the FCB mode, when a gas turbine generator 11 can maintain stable operation of auxiliary machines and other loads 5 for the coal-fired plant and auxiliary machines and other loads 6 for the gas turbine plant, the step 8) is carried out, and otherwise, the step 9) is carried out;
8) after the gas turbine generator 11 operates stably, restarting the coal-fired unit, after the coal-fired generator 1 is subjected to voltage reestablishment, closing a service incoming line circuit breaker 7 by using a synchronization device 22, closing a main transformer high-voltage side circuit breaker 3 at the same time, charging a line, and using the gas turbine generator 11 as a black start power supply;
9) tripping the gas turbine generator 11 and tripping the gas turbine generator outlet circuit breaker 13, tripping the plant 6kV bus section 10, and tripping the plant load circuit breaker 8 of the coal-fired unit and the plant load circuit breaker 9 of the gas turbine;
10) the backup power automatic switching device 24 sends an instruction to the diesel generator 21 to start voltage build-up, the backup power automatic switching device is automatically switched into the diesel generator outlet circuit breaker 20 after the voltage build-up of the diesel generator 21 is successful, the backup power automatic switching device 24 trips out of the security MCC section incoming circuit breaker 17 and is switched into the diesel generator incoming circuit breaker 19, and the security MCC section bus 18 is powered by the diesel generator 21;
11) the safety MCC section bus 18 is switched into a safety MCC section incoming line breaker 17 after no abnormity, the safety PC section bus 15 is powered by a diesel generator 21, the safety PC section bus 15 is switched into a safety PC section incoming line breaker 12 after no abnormity, and a plant 6kV bus section 10 is powered by the diesel generator 21;
12) the gas turbine plant load circuit breaker 9 is sequentially put into a gas turbine plant auxiliary machine and other loads 6, then a gas turbine generator 11 is started, the gas turbine generator 11 is put into a gas turbine generator outlet circuit breaker 13 after voltage is built, and the gas turbine generator 11 supplies power to a plant 6kV bus section 10;
13) disconnecting the diesel generator inlet circuit breaker 19 and the diesel generator outlet circuit breaker 20, and withdrawing the diesel generator 21;
14) the load circuit breaker 8 for merging into the coal-fired plant factory is sequentially put into auxiliary machines and other loads 5 for the coal-fired plant factory, then a gas turbine generator 11 is started, and after the pressure of the coal-fired generator 1 is built, a synchronization device 22 is utilized to merge into a factory incoming line circuit breaker 7;
15) after the operating parameters of the coal-fired generator 1 are not abnormal, a main transformer high-voltage side circuit breaker 3 is switched in to charge the line, and the coal-fired generator 1 is used as a black start power supply.
The invention has the advantages that the northern area is generally lack of hydropower stations and large gas turbine units, but a certain black start power supply is required as a power supply point support. The small new energy power station has the advantages of low access voltage level, limited phase advance capability and generally small capacity, and is not obvious as a black start power supply, while the thermal power plant combined with the FCB function small gas turbine has the characteristics of large capacity, high access voltage level and quick hot start as the black start power supply, has certain phase advance capability, and is very suitable for serving as the black start power supply in the northern area of a large-scale gas turbine unit lacking hydropower.
In the past, the coal-fired unit is used as a black start power supply, a large diesel generator set needs to be used for supplying power in parallel as a start power supply, the investment is large, the idle rate of the diesel generator 21 is high in the normal operation of the unit, and the investment return ratio is poor.
The small-sized gas turbine control system is precise, the FCB is easy to realize, the starting time is short, the idle rate of power supply assets of a plant system of the gas turbine unit is low, the plant power rate can be reduced, a system frequency modulation function can be added, the investment cost is low, and the construction period is short.
After the gas turbine successfully enters the FCB mode, the loss of service power can be effectively avoided, the system of the coal-fired unit can be restored within a short time in a hot state, and even if the FCB mode fails, the gas turbine system can be quickly restarted by using the diesel generator 21 configured per se as a power supply to restore the service power.
Meanwhile, a synchronous device 22 is arranged, so that the risk of non-synchronous switching-on when the service power is recovered is avoided.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.