Control method of AVC substation system interface in smart grid

Abstract

The present invention relates to a control method and logic structure of a smart grid AVC substation system interface, which is characterized in that: the smart grid AVC substation system is connected to the network control system NCS of a power plant to transmit analog control signals, and the smart grid AVC substation system communicates with the main station through the remote monitoring terminal RTU of the power plant to make full use of the original equipment of the power plant; the magnetic increase or demagnetization instruction of the gas-steam combined unit is input to the smart grid AVC substation system through the distributed control system DCS, and transmitted to the excitation regulator of the gas-steam combined unit; remote input and exit control, and magnetic increase or demagnetization logic interlocking are realized in the distributed control system DCS; operating parameters and alarm signals are sent to the distributed control system DCS, and a monitoring screen is set on the display CRT of the distributed control system DCS. It has outstanding substantial characteristics and significant technical progress such as simple structure, low cost, good compatibility, safety and stability.

Description

Technical Field

[0001] The present invention relates to a control method and logic structure of a smart grid AVC substation system interface, which is particularly suitable for controlling a system interface of a 9F-class gas-steam combined unit smart grid AVC substation, and belongs to the technical field of power generation industry and ancillary equipment. Background Art

[0002] AVC is commonly known as smart grid. At present, there are many ways to implement the smart grid AVC substation of power plants in China. One is to use an independent smart grid AVC control system, the second is to implement it in the power plant remote monitoring terminal RTU, and the third is to implement it in the power plant's distributed control system DCS or network control system NCS. Although these implementation methods have their own characteristics and have been applied in engineering, they also play an important role in power plant voltage regulation. However, there are the following problems: (1) The use of an independent AVC control system has problems such as high cost, complex wiring, and large circuit changes; (2) Implementation in the power plant remote monitoring terminal RTU has problems such as high difficulty and easy impact on the original control program; (3) Implementation in the power plant's distributed control DCS or network control system NCS has the problem of incompatibility between gas-steam combined units and coal-fired power plants. Therefore, the three existing technical methods are difficult to meet the control needs of the smart grid AVC substation system of the gas-steam combined unit. Summary of the invention

[0003] One of the purposes of the present invention is to solve the problems of the prior art smart grid AVC substation control system, such as high cost, complex wiring, large or difficult circuit changes, easy impact on the original control program or poor compatibility, and to provide a control method for the smart grid AVC substation system interface, which has outstanding substantial characteristics and significant technical progress such as simple structure, low cost, good compatibility, safety and stability.

[0004] A second objective of the present invention is to provide a control logic structure of a smart grid AVC substation system interface.

[0005] One of the purposes of the present invention can be achieved by adopting the following technical solution:

[0006] The remote control method of the smart grid AVC substation system is characterized by:

[0007] 1) Connect the smart grid AVC substation system through the power plant's network control system NCS to transmit analog control signals, and realize communication between the smart grid AVC substation system and the main station through the power plant's remote monitoring terminal RTU to make full use of the power plant's original equipment; 2) Input the increase or decrease magnetization instructions of the gas-steam combined unit to the smart grid AVC substation system through the distributed control system DCS, and transmit it to the excitation regulator of the gas-steam combined unit; 3) Realize remote input and exit control, and increase or decrease magnetization logic interlock in the distributed control system DCS to simplify external wiring and improve equipment reliability; 4) The operating parameters and alarm signals of the smart grid AVC substation system are sent to the distributed control system DCS, and a monitoring screen is set on the display CRT of the distributed control system DCS to cancel the background management machine, facilitate the operation personnel to monitor the panel and save investment.

[0008] One of the purposes of the present invention can also be achieved by adopting the following technical solution:

[0009] Furthermore, the on / off control command signal of the smart grid AVC substation system includes an AVC on command, an AVC off command, a manual magnetization increase command and a manual magnetization decrease command.

[0010] Furthermore, the distributed control system DCS is connected to the remote on / off signal of the execution terminal of the smart grid AVC, and the operating personnel directly perform on / off operations on the AVC execution terminal through the CRT in the control room; the distributed control system DCS determines whether to allow automatic control based on the "self-test normal" signal sent by the execution terminal of the smart grid AVC. When a self-test normal signal appears, the distributed control system DCS allows the execution terminal of the smart grid AVC to be put into operation; when an abnormal situation occurs in the excitation system, the distributed control system DCS automatically cuts off the execution terminal of the smart grid AVC.

[0011] Furthermore, the automatic control of the smart grid AVC is set to be cut off without constraints, so that the operating personnel can cut off the automatic control of the smart grid AVC under the constraints; the automatic control signal output by the voltage regulator AVR of the smart grid AVC is connected to the distributed control system DCS, and the signal is forwarded to the execution terminal of the smart grid AVC through the distributed control system DCS, and the distributed control system DCS determines whether automatic control is allowed based on this automatic signal.

[0012] Furthermore, the execution terminal of the smart grid AVC sends a protection start-up access to the distributed control system DCS. When the protection start-up signal is received, the distributed control system DCS cuts off the execution terminal of the smart grid AVC. When the smart grid AVC execution terminal is put into use, the operating personnel cannot manually change the reactive power of the unit on the CRT. Only when the smart grid AVC is exited can the distributed control system DCS adjust the reactive power of the unit.

[0013] Furthermore, the increase and decrease magnetic pulse signal sent by the execution terminal of the smart grid AVC is connected to the distributed control system DCS, and forwarded to the signal input end of the voltage regulator AVR through the distributed control system DCS; in the smart grid AVC system, when the increase magnetic locking signal appears, the increase magnetic is locked, and when the decrease magnetic locking signal appears, the decrease magnetic is locked; the distributed control system DCS limits the pulse width of the connected increase and decrease magnetic signal, and when the increase and decrease magnetic signal pulse width exceeds the set value of 3 seconds, the distributed control system DCS automatically cuts off the execution terminal of the smart grid AVC and shields the increase and decrease magnetic outlet.

[0014] Furthermore, in order to prevent the smart grid AVC from being put into operation and causing misadjustment during the SFC dragging of the starting machine, the generator grid-connected signal is set to lock the smart grid AVC input, and the smart grid AVC input is allowed only after the generator is connected to the grid; in order to prevent the local smart grid AVC from being exited before the unit is shut down, resulting in the distributed control system DCS being unable to automatically reduce reactive power when the unit is shut down, the distributed control system DCS is set to automatically exit the smart grid AVC control logic while issuing a shutdown order.

[0015] The second object of the present invention can be achieved by adopting the following technical solution:

[0016] The control logic structure of the smart grid AVC substation system interface is characterized in that it is composed of a power plant remote monitoring structure, a power plant network control system and an AVC substation system structure. The power plant remote monitoring structure is connected to the AVC substation system structure through the network control system to input the status signal of the AVC substation system structure and output the control signal of the AVC substation system structure; the power plant remote monitoring structure includes an over-excitation limit output terminal, a low magnetic limit output terminal, an excitation abnormality alarm input terminal, an AC power supply fault input terminal, a DC power supply fault input terminal, a channel one fault input terminal, a channel two fault input terminal, an excitation system communication terminal TRIP, a voltage transformer PT line break fault input terminal and a rectifier bridge fault input terminal; the power plant network control system includes a grid-connected signal feedback terminal, a voltage regulator AVR automatic signal terminal and a voltage regulator AVR normal signal terminal; the distributed control system includes a manual magnetization instruction input The excitation regulator comprises an AVC increase magnetization locking terminal, an AVC increase magnetization command terminal, an AVC demagnetization locking terminal, an AVC demagnetization command terminal, a generator voltage increase command terminal, and a generator voltage decrease command terminal. The AVC increase magnetization locking terminal, the AVC increase magnetization command terminal, the AVC demagnetization locking terminal, the AVC demagnetization command terminal, the generator voltage increase command terminal, and the generator voltage decrease command terminal are connected to the controlled object through a networked control system to form an excitation regulation structure.

[0017] The second object of the present invention can also be achieved by adopting the following technical solution:

[0018] Furthermore, the fault input terminal of channel one and the fault input terminal of channel two are respectively connected to the engine AVC input signal channel output terminal and the engine AVC exit signal channel output terminal of the AVC substation system structure monitoring, channel one refers to the engine AVC input signal channel, and channel two refers to the engine AVC exit signal channel.

[0019] Furthermore, the voltage regulator AVR is equipped with a fundamental wave, harmonic compound excitation or an AC brushless generator equipped with a permanent magnet generator excitation PGM system, forming a compound excitation regulation structure or a permanent magnet generator excitation structure.

[0020] The present invention has the following outstanding substantive features and significant technical advances:

[0021] 1. The remote control method of the smart grid AVC substation system of the present invention is to connect the smart grid AVC substation system through the network control system NCS of the power plant to transmit analog control signals, and realize the communication between the smart grid AVC substation system and the main station through the remote monitoring terminal RTU of the power plant to make full use of the original equipment of the power plant; input the increase or decrease magnetization instruction of the gas-steam combined unit to the smart grid AVC substation system through the distributed control system DCS, and transmit it to the excitation regulator of the gas-steam combined unit; realize remote input and exit control, and increase or decrease magnetization in the distributed control system DCS Logical interlocking is used to simplify external wiring and improve equipment reliability. The operating parameters and alarm signals of the smart grid AVC substation system are sent to the distributed control system DCS, and a monitoring screen is set on the display CRT of the distributed control system DCS to eliminate the background management machine, facilitate operator monitoring and save investment. Therefore, it can solve the problems of the smart grid AVC substation control system in the prior art, such as high cost, complex wiring, large or difficult circuit changes, easy impact on the original control program or poor compatibility, etc., and has outstanding substantial characteristics and significant technical progress such as simple structure, low cost, good compatibility, safety and stability.

[0022] 2. In the present invention, since the analog quantity required by the smart grid AVC substation system is taken from the NCS system, the communication with the main station is realized through the NCS system RTU, which makes full use of the original equipment and saves investment; the unit increase and decrease magnetization instructions output by the present invention are sent to the excitation regulator through the DCS system, and remote input and exit control and related logical interlocking are realized in the distributed control system DCS, which simplifies external wiring and improves equipment reliability; the important operating parameters and alarm signals of the smart grid AVC substation system are sent to the distributed control system DCS, and a monitoring screen is set on the CRT of the distributed control system DCS, and the background management machine is cancelled, which is convenient for operating personnel to monitor the panel and saves investment.

[0023] 3. The present invention is used for the smart grid AVC substation system of the 9F-class gas-steam combined unit. By constructing the smart grid AVC substation system, the smart grid AVC substation system is interconnected with the central dispatch smart grid AVC master station system, the unit reactive power is automatically adjusted, and the 220KV bus voltage is controlled within the qualified range, which fully meets the relevant technical specifications of the central dispatch, ensuring the safe and stable operation of the power grid and reducing the workload of the operating personnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural block diagram of the control logic structure of the smart grid AVC substation system interface involved in the present invention.

[0025] Figure 2 It is a control logic schematic diagram of a specific embodiment of the present invention. DETAILED DESCRIPTION Specific embodiment 1:

[0027] Reference Figure 1 and Figure 2 The control logic structure of the smart grid AVC substation system interface involved in this specific embodiment 1 is composed of a power plant remote monitoring structure, a power plant network control system and an AVC substation system structure. The power plant remote monitoring structure is connected to the AVC substation system structure through the network control system to input the status signal of the AVC substation system structure and output the control signal of the AVC substation system structure; the power plant remote monitoring structure includes an over-excitation limit output terminal, a low magnetic limit output terminal, an excitation abnormality alarm input terminal, an AC power supply fault input terminal, a DC power supply fault input terminal, a channel 1 fault input terminal, a channel 2 fault input terminal, an excitation system communication terminal TRIP, a voltage transformer PT line break fault input terminal and a rectifier bridge fault input terminal; the power plant network control system includes a grid-connected signal feedback terminal, a voltage regulator AVR automatic signal terminal and a voltage regulator AVR normal signal terminal; the distributed control system includes a manual magnetization pointer The excitation regulator comprises an input terminal, a manual demagnetization instruction input terminal, a normal shutdown instruction input terminal, a maintenance shutdown instruction input terminal, an AVC input instruction input terminal, an AVC device input feedback terminal, an AVC device protection start terminal, an AVC exit instruction input terminal, a voltage regulator AVR normal signal output terminal, an engine AVC input signal output terminal and an engine AVC exit signal output terminal. The manual magnetization instruction input terminal and the manual demagnetization instruction input terminal are connected to the input terminal of the excitation regulator; the excitation regulator is provided with an AVC magnetization locking terminal, an AVC magnetization instruction terminal, an AVC demagnetization locking terminal, an AVC demagnetization instruction terminal, a generator voltage increase command terminal and a generator voltage reduction command terminal; the AVC magnetization locking terminal, the AVC magnetization instruction terminal, the AVC demagnetization locking terminal, the AVC demagnetization instruction terminal, the generator voltage increase command terminal and the generator voltage reduction command terminal are connected to the controlled object through a networked control system to form an excitation regulation structure.

[0028] Furthermore, the fault input terminal of channel 1 and the fault input terminal of channel 2 are respectively connected to the engine AVC input signal channel output terminal and the engine AVC exit signal channel output terminal of the AVC substation system structure monitoring, channel 1 refers to the engine AVC input signal channel, and channel 2 refers to the engine AVC exit signal channel.

[0029] Furthermore, the voltage regulator AVR is equipped with a fundamental wave, harmonic compound excitation or an AC brushless generator equipped with a permanent magnet generator excitation PGM system, forming a compound excitation regulation structure or a permanent magnet generator excitation structure.

[0030] The remote control method of the smart grid AVC substation system involved in this specific embodiment 1 is characterized by:

[0031] 1) The smart grid AVC substation system is connected through the power plant's network control system NCS to transmit analog control signals, and the smart grid AVC substation system communicates with the main station through the power plant's remote monitoring terminal RTU to make full use of the power plant's original equipment;

[0032] 2) Input the magnetization increase or demagnetization instruction of the gas-steam combined unit to the smart grid AVC substation system through the distributed control system DCS, and transmit it to the excitation regulator of the gas-steam combined unit;

[0033] 3) Realize remote input and output control and magnetic increase or decrease logic interlock in the distributed control system DCS to simplify external wiring and improve equipment reliability;

[0034] 4) The operating parameters and alarm signals of the smart grid AVC substation system are sent to the distributed control system DCS, and a monitoring screen is set on the display CRT of the distributed control system DCS to eliminate the background management machine, facilitate the operation personnel to monitor the panel and save investment.

[0035] In the remote control method described in this embodiment:

[0036] The on / off control command signal of the smart grid AVC substation system includes an AVC on command, an AVC off command, a manual magnetization increase command and a manual magnetization decrease command.

[0037] The remote on / off signal of the execution terminal of the smart grid AVC is accessed from the distributed control system DCS, and the operating personnel directly perform on / off operations on the AVC execution terminal through the CRT in the control room.

[0038] The distributed control system DCS determines whether to allow automatic control based on the "normal self-test" signal sent by the execution terminal of the smart grid AVC. When a normal self-test signal appears, the distributed control system DCS allows the execution terminal of the smart grid AVC to be put into operation; when an abnormal situation occurs in the excitation system, the distributed control system DCS automatically cuts off the execution terminal of the smart grid AVC.

[0039] The automatic control of the AVC of the smart grid is set to be cut off without constraints, so that the operation personnel can cut off the automatic control of the AVC of the smart grid under the constraints;

[0040] The automatic control signal output by the voltage regulator AVR of the smart grid AVC is connected to the distributed control system DCS, and the signal is forwarded to the execution terminal of the smart grid AVC through the distributed control system DCS. The distributed control system DCS determines whether automatic control is allowed based on this automatic signal.

[0041] The execution terminal of the smart grid AVC sends a protection start to access the distributed control system DCS. When receiving the protection start signal, the distributed control system DCS cuts off the execution terminal of the smart grid AVC. When the smart grid AVC execution terminal is put into use, the operating personnel cannot change the unit reactive power manually on the CRT. Only when the smart grid AVC is exited can the distributed control system DCS adjust the unit reactive power.

[0042] The increase and decrease magnetic pulse signal sent by the execution terminal of the smart grid AVC is connected to the distributed control system DCS, and is transferred to the signal input end of the voltage regulator AVR through the distributed control system DCS.

[0043] In the smart grid AVC system, when a magnetization lock signal appears, magnetization is locked, and when a magnetization lock signal appears, magnetization is locked; the distributed control system DCS limits the pulse width of the connected magnetization increase and decrease signal. When the pulse width of the magnetization increase and decrease signal exceeds the set value of 3 seconds, the distributed control system DCS automatically cuts off the execution terminal of the smart grid AVC and blocks the magnetization increase and decrease export.

[0044] In order to prevent the smart grid AVC from being put into operation during the SFC dragging of the start-up and causing misadjustment, the generator grid-connected signal is set to lock the smart grid AVC input, and the smart grid AVC input is allowed only after the generator is connected to the grid; in order to prevent the local smart grid AVC from being exited before the unit is shut down, resulting in the distributed control system DCS being unable to automatically reduce reactive power when the unit is shut down, the distributed control system DCS is set to automatically exit the smart grid AVC control logic while issuing a shutdown order.

[0045] The voltage regulator AVR is equipped with an AC brushless generator with a fundamental wave, harmonic compound excitation or a permanent magnet generator excitation PGM system. Since the transmission ratio between the generator and the engine is fixed, the speed of the generator will change with the change of the engine speed. During the operation of the car, the engine speed varies in a wide range, and the terminal voltage of the generator will also vary in a wide range with the change of the engine speed. The generator requires a stable voltage to supply power to electrical equipment and charge the battery, so in order to keep the voltage at a certain value basically unchanged, the output voltage of the generator must be adjusted.

[0046] The further working principle of this embodiment is described as follows:

[0047] The remote control switch-on / off signal (dry contact) of the smart grid AVC execution terminal is connected from the distributed control system DCS, and the operator can directly switch-on / off the smart grid AVC execution terminal in the CRT of the centralized control room; there are no constraints on switching off the smart grid AVC automatic control, and the operator can switch off the smart grid AVC automatic control at any time and in any state; when the smart grid AVC execution terminal is put into operation, the operator cannot manually change the unit reactive power at the CRT; only when the smart grid AVC is exited, the distributed control system DCS can adjust the unit reactive power;

[0048] The distributed control system DCS determines whether automatic control is allowed based on the "normal self-test" signal sent by the smart grid AVC execution terminal. Only when the normal self-test signal appears can the smart grid AVC execution terminal be allowed to be put into operation; the AVR automatic signal is connected to the DCS system, and the signal is forwarded to the smart grid AVC execution terminal through the distributed control system DCS. The distributed control system DCS determines whether automatic control is allowed based on this signal; if the excitation system is abnormally affected, the distributed control system DCS automatically cuts off the smart grid AVC execution terminal;

[0049] The magnetic increase and decrease pulse signals sent by the smart grid AVC execution terminal are connected to the distributed control system DCS and forwarded to the AVR through the distributed control system DCS; the magnetic increase blocking signal appears in the smart grid AVC system to block magnetic increase, and the magnetic decrease blocking signal appears to block magnetic decrease;

[0050] The distributed control system DCS should limit the pulse width of the incoming increase and decrease magnetic signal. When the pulse width of the increase and decrease magnetic signal exceeds the set value (3S), the distributed control system DCS can automatically cut off the smart grid AVC execution terminal and shield the increase and decrease magnetic outlet;

[0051] The smart grid AVC execution terminal sends a protection start signal to access the distributed control system DCS. When receiving the protection start signal, the distributed control system DCS cuts off the smart grid AVC execution terminal;

[0052] To prevent the smart grid AVC from being put into operation during the SFC dragging of the start-up and causing misregulation, the generator grid-connected signal is set to lock the smart grid AVC input. The smart grid AVC input is allowed only after the generator is connected to the grid; to prevent the distributed control system DCS from automatically reducing reactive power when the unit is shut down due to the failure to exit the local smart grid AVC before the unit is shut down, the distributed control system DCS is set to automatically exit the smart grid AVC logic at the same time when issuing a shutdown order.

[0053] A smart grid AVC substation control screen is provided in the distributed control system DCS, which can realize the smart grid AVC substation system on / off control and display of status signals, alarm signals and important parameters.

Claims

1. A remote control method for a smart grid AVC substation system, characterized in that: 1) The smart grid AVC substation system is connected through the power plant's network control system NCS to transmit analog control signals, and the smart grid AVC substation system communicates with the main station through the power plant's remote monitoring terminal RTU to make full use of the power plant's original equipment; 2) Input the magnetization increase or demagnetization instruction of the gas-steam combined unit to the smart grid AVC substation system through the distributed control system DCS, and transmit it to the excitation regulator of the gas-steam combined unit; 3) Realize remote input and output control and magnetic increase or decrease logic interlock in the distributed control system DCS to simplify external wiring and improve equipment reliability; 4) The operation parameters and alarm signals of the smart grid AVC substation system are sent to the distributed control system DCS, and the monitoring screen is set on the display CRT of the distributed control system DCS to cancel the background management machine, facilitate the operation personnel to monitor the panel and save investment; The remote switching signal of the execution terminal of the smart grid AVC is accessed from the distributed control system DCS, and the operating personnel directly switch the AVC execution terminal on / off through the CRT in the control room; the distributed control system DCS determines whether to allow automatic control based on the "self-check normal" signal sent by the execution terminal of the smart grid AVC. When the self-check normal signal appears, the distributed control system DCS allows the execution terminal of the smart grid AVC to be switched on; when an abnormal situation occurs in the excitation system, the distributed control system DCS automatically cuts off the execution terminal of the smart grid AVC.

2. The remote control method of the smart grid AVC substation system according to claim 1, characterized in that: The on / off control command signal of the smart grid AVC substation system includes an AVC on command, an AVC off command, a manual magnetization increase command and a manual magnetization decrease command.

3. The remote control method of the smart grid AVC substation system according to claim 1, characterized in that: The automatic control of the smart grid AVC is set to be cut off without constraints, so that the operating personnel can cut off the automatic control of the smart grid AVC under the constraints; the automatic control signal output by the voltage regulator AVR of the smart grid AVC is connected to the distributed control system DCS, and the signal is forwarded to the execution terminal of the smart grid AVC through the distributed control system DCS, and the distributed control system DCS determines whether automatic control is allowed based on this automatic signal.

4. The remote control method of the smart grid AVC substation system according to claim 1, characterized in that: The execution terminal of the smart grid AVC sends a protection start to access the distributed control system DCS. When receiving the protection start signal, the distributed control system DCS cuts off the execution terminal of the smart grid AVC. When the smart grid AVC execution terminal is put into use, the operating personnel cannot change the unit reactive power manually on the CRT. Only when the smart grid AVC is exited can the distributed control system DCS adjust the unit reactive power.

5. The remote control method of the smart grid AVC substation system according to claim 1, characterized in that: The increase and decrease magnetic pulse signal sent by the execution terminal of the smart grid AVC is connected to the distributed control system DCS, and forwarded to the signal input end of the voltage regulator AVR through the distributed control system DCS; in the smart grid AVC system, when the increase magnetic locking signal appears, the increase magnetic is locked, and when the decrease magnetic locking signal appears, the decrease magnetic is locked; the distributed control system DCS limits the pulse width of the connected increase and decrease magnetic signal. When the pulse width of the increase and decrease magnetic signal exceeds the set value of 3 seconds, the distributed control system DCS automatically cuts off the execution terminal of the smart grid AVC and shields the increase and decrease magnetic outlet.

6. The remote control method of the smart grid AVC substation system according to claim 1, characterized in that: In order to prevent the smart grid AVC from being put into operation during the SFC dragging of the start-up and causing misadjustment, the generator grid-connected signal is set to lock the smart grid AVC input, and the smart grid AVC input is allowed only after the generator is connected to the grid; in order to prevent the local smart grid AVC from being exited before the unit is shut down, resulting in the distributed control system DCS being unable to automatically reduce reactive power when the unit is shut down, the distributed control system DCS is set to automatically exit the smart grid AVC control logic while issuing a shutdown order.

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