CN115333227A - System for preventing electric power from being reversely transmitted - Google Patents

System for preventing electric power from being reversely transmitted Download PDF

Info

Publication number
CN115333227A
CN115333227A CN202210936254.9A CN202210936254A CN115333227A CN 115333227 A CN115333227 A CN 115333227A CN 202210936254 A CN202210936254 A CN 202210936254A CN 115333227 A CN115333227 A CN 115333227A
Authority
CN
China
Prior art keywords
power
module
preventing
grid
power generation
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202210936254.9A
Other languages
Chinese (zh)
Inventor
孙艳超
郭兵兵
杨婀
李平
何伟
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Jiangxi Huadian Electrical Power Co ltd
Original Assignee
Jiangxi Huadian Electrical Power Co ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Jiangxi Huadian Electrical Power Co ltd filed Critical Jiangxi Huadian Electrical Power Co ltd
Priority to CN202210936254.9A priority Critical patent/CN115333227A/en
Publication of CN115333227A publication Critical patent/CN115333227A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
    • H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
    • H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
    • H02J9/08—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems requiring starting of a prime-mover
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H1/00—Details of emergency protective circuit arrangements
    • H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H11/00—Emergency protective circuit arrangements for preventing the switching-on in case an undesired electric working condition might result

Landscapes

  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Supply And Distribution Of Alternating Current (AREA)

Abstract

The invention provides a system for preventing electric power from being transmitted reversely, which comprises a power generation module, a load module and an external power grid module, wherein the power generation module and the external power grid module supply power to the load module; or, the electric power feedback prevention module comprises a power generation power monitor for monitoring the power of the power generation module, an external grid power monitor for monitoring the input power of the external grid module and a controller for controlling the power generation power of the power generation module.

Description

System for preventing electric power from being reversely transmitted
Technical Field
The invention belongs to the field of electric power, and particularly relates to the field of electric power generation and transmission.
Background
The screw expander is a power machine which utilizes industrial waste heat and residual gas to push a screw rotor to rotate and drive a generator to generate electricity, and the generated electricity can be supplied to various industrial loads on site. The twin-screw expander is mainly a screw expander composed of a pair of screw rotors engaged with each other.
With the diversification of application markets of the screw expansion generator set, the generated energy of the generator set is larger than the power consumption requirements of special places, industries and the like in some special places, industries and the like, and the extra electric quantity can be automatically transmitted back to a previous-stage power grid (an external power grid) through a transformer. The property of the upper-level power grid (external power grid) belongs to the national power grid, and the external power grid is not allowed in the case of reverse power transmission. The power generated by the self-contained power station can only be supplied to matched factories for use and cannot be transmitted to an external power grid. Therefore, the self-contained power station is connected with an external power grid and only used for providing a standby power supply for the self-contained power station, and in case of a fault of a self-contained power station unit, the power consumption of a factory can be guaranteed through power transmission of the external power grid. When the self-contained power station unit is started initially, a starting power supply can be obtained from a power grid, namely grid connection is carried out without surfing the Internet. For example, in a cogeneration company, the total load is within 1800kW, but the power of an assembly machine of an internal generator reaches 2000kW, and similarly, the situation is also rare and rare in the fields of hazardous waste incineration, waste heat boiler power generation, natural valve station differential pressure power generation and the like.
Disclosure of Invention
The invention provides a system for preventing electric power from being transmitted reversely, which comprises a power generation module, a load module and an external power grid module, wherein the power generation module and the external power grid module supply power to the load module, an electric power reverse transmission prevention module is arranged between the external power grid module and the load module, the electric power reverse transmission prevention module comprises a circuit breaker, and the on-off of the circuit breaker is controlled by monitoring the electric power transmission direction between the external power grid module and the load module. The embodiment aims at solving the technical problem that the surplus electricity of the generator set of the internal power grid in the prior art is reversely transmitted to the external power grid by monitoring the current direction between the external power grid and the internal load.
Furthermore, the power reversal prevention module further comprises a microcomputer comprehensive protection device used for monitoring the power transmission direction between the external power grid module and the load module.
Further, the power generation module comprises a generator module and a screw expander module.
Furthermore, the electric power feedback prevention module further comprises a regulating valve which is arranged on the air inlet pipe of the screw expander module and is controlled by the generated power controller.
The second embodiment of the invention provides a system for preventing electric power from being transmitted reversely, which comprises a power generation module, a load module and an external power grid module, wherein the power generation module and the external power grid module supply power to the load module, an electric power transmission preventing module is arranged between the power generation module and the load module, and the electric power transmission preventing module comprises a power generation power monitor for monitoring the power of the power generation module and an external power monitor for monitoring the input power of the external power grid module. The embodiment aims to adjust the output power of the power generation module by monitoring and comparing the power so as to solve the technical problem that the surplus power of the generator set of the internal power grid in the prior art is transmitted to the external power grid.
Further, the anti-power-return module further comprises a circuit breaker arranged between the external power grid module and the load module.
Furthermore, the power generation module comprises a generator module and a screw expander module.
Furthermore, the electric power feedback prevention module further comprises a regulating valve which is arranged on the air inlet pipe of the screw expander module and is controlled by the generated power controller.
Still further, the screw expander die set comprises a twin screw expander.
The invention has the following beneficial effects:
1. a microcomputer integrated protection device installed in the switch cabinet is used for monitoring the direction of current at a junction breaker QF1 of an internal power grid and an external power grid in real time to prevent electric power of the internal power grid from being reversely transmitted. Normally, current flows from the external grid into the internal grid, but when a power back-up (current flows from the internal grid into the external grid) occurs, the circuit breaker QF1 is automatically opened while the generator module of the power generation module stops working to prevent the power back-up.
2. The interface of the load module and the power generation module is provided with 1 power electric meter which can read the power Pg of the generator set, and the P1 and the Pg are read into the speed regulating system in a communication mode to carry out automatic centralized monitoring operation, judgment and control.
The output power of the screw expansion generator set is adjusted by adjusting the opening of the steam inlet adjusting valve of the screw expansion generator set, the output power Pg of the screw expansion generator set is set as a feedback parameter, the SP is set point, PID control is carried out on the opening of the steam inlet adjusting valve of the screw expansion generator set, electric power feedback is prevented through the above modes, and the power of the generator is prevented from exceeding rated power.
Drawings
FIG. 1 is a schematic diagram of an embodiment of the present invention for preventing power from being transmitted back to an external power grid by monitoring the direction of current flow between the external power grid and an internal load;
fig. 2 is a schematic diagram of adjusting the output power of the power generation module by monitoring and comparing the power according to a second embodiment of the present invention, so as to prevent internal power from being transmitted back to the external power grid;
FIG. 3 is a logic flow diagram of a system according to a second embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Normally current flows from the external grid module into the load module. However, when the sum of the power input to the load module by the external grid module and the power generation module is greater than or much greater than the power consumption of the load module, a current may flow in a reverse direction from the load module to the external grid module, that is, a reverse power transmission may occur.
The first embodiment is as follows:
referring to fig. 1, the present embodiment provides a system for preventing power from being sent backwards, including a power generation module, a load module, and an external power grid module, where the power generation module and the external power grid module supply power to the load module, a power-return prevention module is disposed between the external power grid module and the load module, and the power-return prevention module includes a circuit breaker, and the on-off of the circuit breaker is controlled by monitoring a power transmission direction between the external power grid module and the load module. The embodiment aims at solving the technical problem that surplus electricity of the generator set of the internal power grid in the prior art is reversely transmitted to the external power grid by monitoring the current direction between the external power grid and the internal load.
Furthermore, the power reversal prevention module further comprises a microcomputer comprehensive protection device used for monitoring the power transmission direction between the external power grid module and the load module.
Furthermore, the power generation module comprises a generator module and a screw expander module.
Furthermore, the anti-electric-power-feedback module further comprises a regulating valve which is arranged on the air inlet pipe of the screw expander module and is controlled by the generated power controller.
The microcomputer integrated protection device is used for monitoring the direction of current at the position of a breaker QF1 at the junction of the external power grid module and the load module in real time, when the current is reversed and flows to the external power grid module from the load module, the controller automatically controls the breaker QF1 to be switched off, and meanwhile, the controller automatically controls the generator module to stop working.
When the condition of reverse power transmission occurs, the current direction is changed, the current flows into an external power grid from the inside of a plant, and when the condition occurs, the breaker QF1 automatically opens the brake, and the screw expansion generator set stops, as shown in figure 1.
Example two:
as shown in fig. 2 and fig. 3, this embodiment provides a system for preventing electric power from being sent back, including a power generation module, a load module and an external power grid module, where the power generation module and the external power grid module supply power to the load module, an electric power return prevention module is disposed between the power generation module and the load module, and the electric power return prevention module includes a power generation monitor for monitoring power of the power generation module and an external power grid monitor for monitoring input power of the external power grid module. The embodiment aims to adjust the output power of the power generation module by monitoring and comparing the power so as to solve the technical problem that the surplus power of the generator set of the internal power grid in the prior art is transmitted to the external power grid.
Further, the anti-power-return module further comprises a circuit breaker arranged between the external power grid module and the load module.
Furthermore, the power generation module comprises a generator module and a screw expander module.
Furthermore, the anti-electric-power-feedback module further comprises a regulating valve which is arranged on the air inlet pipe of the screw expander module and is controlled by the generated power controller.
Still further, the screw expander module comprises a twin screw expander.
The method comprises the steps of installing a power meter at the junction of an external power grid module and a load module, reading the power P1 input into the load module by the external power grid module, installing 1 power meter at the junction of the load module and a power generation module, reading the actual output power Pg of the power generation module, and reading the P1 and the Pg into a screw expander speed regulation system of the power generation module in a communication mode for operation. The actual power Pm of the load module is constantly changing and can be estimated as Pm = P1+ Pg.
The opening of the regulating valve on the air inlet pipe of the screw expander module is regulated by the speed regulating system to regulate the rotating speed of the screw expander module, so that the output power of the generator module in the power generation module is controlled.
And taking the output power Pg of the power generation module as a feedback parameter. Setting SP as the set point of the speed regulation system, carrying out automatic dynamic assignment by manual or system, carrying out PID control on the opening of the regulating valve on the air inlet pipe of the screw expander module, and forming logic linkage with the circuit breakers QF1 and QF 2.
When the power generation module is started initially, the system automatically delays for 30 seconds to start the automatic monitoring and controlling power function, and unstable interference factors are filtered. After the speed regulating system is started to automatically and circularly operate in the whole flow, once per second, the system automatically judges and sets the SP value according to the monitored power of each part and the following setting program.
When the power P1 input into the load module by the external power grid is monitored to be less than 0, the current flows backwards to the external power grid in the forward direction, the system automatically sends a command, the breaker QF2 receives the command to perform brake opening, the generator stops, and the situation of backward power transmission is prevented from continuing.
The speed regulating system continuously compares the SP with the rated power Pe of the generator, and as long as the SP is less than or equal to the Pe, the electric generator module in the power generation module does not generate excessive power. The over-generation is the situation that the actual power generation power of the generator exceeds the rated power, at the moment, the rotating speed of the generator exceeds the rated rotating speed, copper wires in the generator are overheated, and the copper wires burn to damage the generator after a long time. The rated power of the generator is designed by matching with the screw expander module under most working conditions of the use site during initial model selection, and the mantissa of the rated power is usually about a whole hundred, such as 2300 kW, so that the possibility of over-generation exists under special conditions. And if SP & gtPe, automatically assigning SP = Pe to SP by the system, and reducing the power of the generator to the rated power.
Meanwhile, in order to avoid the phenomenon of regulation lag of the regulating valve, the SP setting is slightly smaller than Pm (for example, 50kW is selected), a margin is reserved to prevent the power of the generator from increasing too fast (when Pg is less than or equal to 50kW, the breaker QF2 is opened), so that an assignment statement SP = Pm-50=p1+pg-50 is obtained, the power Pm of the load module is subtracted by 50kW, that is, the power P1 input to the load module by the external power grid is added to the actual output power Pg of the generator module and then subtracted by 50kW, and the operation result of the assignment statement is set as a new SP value.
Within the range that P1 is more than or equal to 0 and SP is less than or equal to Pe, the assignment statement enables Pg to be reduced when P1 is reduced and Pg to be increased when P1 is increased. That is, if the power consumption of the load is reduced, P1 is reduced immediately, and the system automatically controls the generator to reduce the power generation according to the program, and vice versa. The embodiment can prevent the generator from over-transmitting, avoid waste and risks, also can pre-adjust in advance, and prevent the occurrence of reverse power transmission.
In the description herein, references to the description of the terms "example one," "example two," etc. mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics, etc., described may be combined, coupled, or combined in any suitable manner in any one or more embodiments or examples.
The above description is only a preferred embodiment of the present invention, but the implementation of the present invention is not limited to the above embodiment, and a person skilled in the art can still modify the technical solutions described in the above embodiments, or make equivalent changes to some technical features. The configuration, model, size, coefficient index, and the like of all the components not specifically described are general techniques, and can be replaced as long as the object can be achieved.
Any modification, replacement, change, modification, combination, simplification and the like which are made within the spirit and principle of the present invention, or which are directly or indirectly applied to other related technical fields, shall fall within the protection scope of the present invention.

Claims (10)

1. A system for preventing electric power from being sent back comprises an electric power generation module, a load module and an external power grid module, wherein the electric power generation module and the external power grid module supply power to the load module.
2. The system for preventing power reversal of claim 1, wherein: the power reverse transmission prevention module further comprises a microcomputer comprehensive protection device used for monitoring the power transmission direction between the external power grid module and the load module.
3. The system for preventing power reversal of claim 1, wherein: the power generation module comprises a generator module and a screw expander module.
4. The system for preventing electric power from being sent back according to claim 3, wherein: the screw expander module comprises a double-screw expander.
5. A system for preventing electric power from being transmitted reversely comprises a power generation module, a load module and an external power grid module, wherein the power generation module and the external power grid module supply power to the load module.
6. The system for preventing power reversal of claim 5, wherein: the anti-power-return module further comprises a circuit breaker arranged between the external power grid module and the load module.
7. The system for preventing electric power from being sent back according to any one of claims 5 or 6, wherein: the power generation module comprises a generator module and a screw expander module.
8. The system for preventing power return of claim 7, wherein: the electric power feedback prevention module further comprises a regulating valve which is arranged on the air inlet pipe of the screw expander module and is controlled by the power generation controller.
9. The system for preventing power return of claim 8, wherein: the screw expander module comprises a double-screw expander.
10. The system for preventing power return of claim 8, wherein: the system automatically monitors, judges and controls to prevent the power of the generator from exceeding the rated power and prevent the occurrence of electric power feedback.
CN202210936254.9A 2022-08-05 2022-08-05 System for preventing electric power from being reversely transmitted Pending CN115333227A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210936254.9A CN115333227A (en) 2022-08-05 2022-08-05 System for preventing electric power from being reversely transmitted

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210936254.9A CN115333227A (en) 2022-08-05 2022-08-05 System for preventing electric power from being reversely transmitted

Publications (1)

Publication Number Publication Date
CN115333227A true CN115333227A (en) 2022-11-11

Family

ID=83922634

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210936254.9A Pending CN115333227A (en) 2022-08-05 2022-08-05 System for preventing electric power from being reversely transmitted

Country Status (1)

Country Link
CN (1) CN115333227A (en)

Similar Documents

Publication Publication Date Title
Bagnasco et al. Management and dynamic performances of combined cycle power plants during parallel and islanding operation
EP2128955B1 (en) Variable rate feedforward control based on set point rate of change
JP5216181B2 (en) Wind park driving method
Hurley et al. The adverse effects of excitation system var and power factor controllers
US6404075B1 (en) Uninterruptible power generation system
KR20170086408A (en) Method for operating a power plant, and power plant
CN111412023A (en) Coordination control method for realizing stable operation of steam-electricity dual-drive system
CN218472839U (en) System for preventing electric power from being reversely transmitted
CN114204604A (en) Load sharing with interconnect power generation
CN115333227A (en) System for preventing electric power from being reversely transmitted
CN115788612B (en) Start-stop mode of differential pressure turbine expansion unit
Elamari et al. Frequency based control of electric water heaters in small PV-diesel hybrid mini-grids
CN116292063A (en) Pipeline type asynchronous hydroelectric generation control system and control strategy thereof
CN110970926A (en) Auxiliary frequency modulation device based on energy-saving technology for thermal power plant and control method thereof
GB2166198A (en) Improved steam turbine load control in a combined cycle electrical power plant
CN214227844U (en) Grid-connected management system for generator sets of different models
CN211266494U (en) Auxiliary frequency modulation device based on energy-saving technology of thermal power plant
RU2550154C2 (en) Method for control of tap changer under load for forced excitation circuit, respective unit and forced excitation circuit with this unit
CN113067359B (en) Direct-current power distribution voltage stabilizing system with intelligent bypass function and control method
CN113872246A (en) Building type distributed micro-grid regulation and control system and method
CN111654217B (en) Active power control method for asynchronous generator set of heat supply network head station based on current control
JP2002083619A (en) Control method of fuel cell composite power generating system
CN106887992A (en) A kind of electric energy conversion of many buses and switching system
CN106849090A (en) A kind of electric energy conversion of new multiport and switching system
CN207021922U (en) A kind of electric energy conversion of more buses and switching system

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination