A nuclear energy heating system and its overspeed protection control signal transmission method

Abstract

The present invention discloses a nuclear energy heating system and an overspeed protection control signal transmission method thereof, wherein the overspeed protection control signal transmission method of the nuclear energy heating system comprises: after the steam turbine auxiliary system receives the overspeed protection control signal, the overspeed protection control signal is transmitted to the heating system respectively through multiple groups of signal transmission devices connected between the steam turbine auxiliary system and the heating system; if the heating system receives at least two groups of the multiple groups of overspeed protection control signals, a control signal is output, and the control signal is used to control the shutdown of the controlled equipment between the heating system and the steam turbine auxiliary system. The present invention is applicable to the overspeed protection control when the nuclear power unit is supplying heat to the outside, and can improve the reliability of signal transmission, shorten the transmission time, and improve the safety of the unit.

Description

Technical Field

[0001] The invention belongs to the field of nuclear energy heating system equipment, and in particular relates to a nuclear energy heating system and an overspeed protection control signal transmission method thereof. Background Art

[0002] As the adjustment of energy structure continues to increase, the advantages of nuclear energy as a clean energy source continue to be reflected. Nuclear energy heating can solve the urban energy supply, reduce transportation pressure and eliminate the environmental pollution caused by burning coal. At present, the requirements for nuclear power units are no longer limited to power generation, but also require the configuration of urban heating function to solve the environmental pollution problems caused by existing coal-fired heating plants.

[0003] Overspeed Protection Control (OPC) is a protection control that inhibits overspeed of steam turbine generator sets. Its function is to close all regulating valves when the steam turbine overspeeds to prevent the turbine speed from further increasing. Currently, among the large nuclear power units put into operation in China, there is no application practice of using steam turbine extraction for external commercial heating.

[0004] The OPC signal in the thermal power unit heating project is a communication signal taken from the control system network CPU, and no hard wiring is used. The OPC signal in the thermal power unit heating project takes one communication signal from the control system network CPU. There is a response time (about 200ms) when the signal communication between different CPUs. This response time may have an impact on the safety of the nuclear power unit steam turbine; in addition, for important signals such as OPC, only one communication signal is taken in the thermal power unit heating project, which has a hidden danger of signal reliability. Summary of the invention

[0005] In view of the above problems, the technical solution adopted by the present invention is: a method for transmitting an overspeed protection control signal of a nuclear energy heating system, comprising:

[0006] After the steam turbine auxiliary system receives the overspeed protection control signal, it transmits it to the heating system through a plurality of signal transmission devices connected between the steam turbine auxiliary system and the heating system;

[0007] If the heating system receives at least two of the multiple groups of overspeed protection control signals, it outputs a control signal, and the control signal is used to control the shutdown of the controlled equipment between the heating system and the steam turbine auxiliary system.

[0008] Optionally, in the heating system, the scanning period of the overspeed protection control signal is 30 to 60 ms.

[0009] Optionally, the controlled equipment includes a regulating steam valve and a steam extraction check valve connected between the heating system and the steam turbine auxiliary system.

[0010] Optionally, before the steam turbine auxiliary system receives the overspeed protection control signal, the method further includes:

[0011] When the steam turbine generator set is in load rejection operation, the overspeed protection control system is triggered to generate a plurality of groups of overspeed protection control signals;

[0012] A plurality of groups of the overspeed protection control signals are transmitted to the relay;

[0013] The relay controls the connection of the pressure oil and the return oil according to the overspeed protection control signal, and adjusts the high-pressure speed regulating valve;

[0014] A plurality of groups of overspeed protection control signals are respectively transmitted to the steam turbine auxiliary system after being expanded by the relay.

[0015] Optionally, the signal transmission device is also connected between the heating system and the controlled device, and the control signal is transmitted through the signal transmission device;

[0016] The signal transmission device includes a connection terminal and a cable connected to the connection terminal.

[0017] And, a nuclear energy heating system, comprising a first controller, a second controller and a plurality of groups of signal transmission devices arranged between the first controller and the second controller;

[0018] The first controller is located in a steam turbine auxiliary system in a nuclear power generation system, and is used to send the received overspeed protection control signal to the second controller through a plurality of groups of the signal transmission devices;

[0019] The second controller is located in the heating system and is used to receive the overspeed protection control signal. If at least two of the multiple groups of overspeed protection control signals are received, the second controller outputs a control signal, which is used to control the shutdown of the controlled equipment between the heating system and the turbine auxiliary system.

[0020] Optionally, in the second controller, the scanning period of the overspeed protection control signal is 30 to 60 ms.

[0021] Optionally, the nuclear energy heating system also includes a third controller, which is located in the overspeed protection control system and is used to trigger the overspeed protection control system to generate and output multiple groups of overspeed protection control signals when the steam turbine generator set is running in load shedding mode.

[0022] Optionally, it also includes a relay cabinet, which includes a plurality of relays corresponding one-to-one to the multiple groups of overspeed protection control signals, and the relays are used to receive the multiple groups of overspeed protection control signals output by the third controller and transmit them to the first controller after expansion.

[0023] Optionally, the relay is also used to control the connection of pressure oil and return oil according to the overspeed protection control signal, and to reduce the high-pressure speed regulating valve.

[0024] The present invention adopts the above technical solution, so it has the following beneficial effects: it is suitable for overspeed protection control of nuclear power units when supplying heat to the outside, can improve signal transmission reliability, shorten transmission time, and improve unit safety.

[0025] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 A signal transmission flow chart of a nuclear energy heating system according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] like Figure 1 The signal transmission flow chart of the nuclear energy heating system shown in the figure, the present invention provides an embodiment of the overspeed protection control signal transmission method of the nuclear energy heating system, comprising:

[0030] S1: When the steam turbine generator set is in load rejection operation, the overspeed protection control system is triggered to generate multiple groups of overspeed protection control signals (i.e., OPC signals);

[0031] S2: multiple groups of overspeed protection control signals are transmitted to the relay;

[0032] The number of relays is the same as the number of groups of OPC signals, and each group of OPC signals is connected to a relay in a one-to-one correspondence. Specifically, a plurality of relays are located in a relay cabinet.

[0033] S3: The relay controls the connection of the pressure oil and the return oil according to the OPC signal, and adjusts the high-pressure speed regulating valve to a small value;

[0034] In the overspeed protection control system, it is mainly composed of two OPC solenoid valves, each regulating valve unloading valve, and OPC pipeline. When the relay receives the OPC signal, the OPC solenoid valve is activated to connect the pressure oil and return oil (pressure oil is hydraulic oil, which is the working medium for the hydraulic control system of the steam turbine. Return oil refers to the working medium in the hydraulic control circuit), and the high-pressure speed regulating valve is quickly closed (the high-pressure speed regulating valve is one of the combined valves installed at the steam inlet of the steam turbine. By adjusting its opening, the steam inlet flow of the entire steam turbine can be controlled) to ensure that the unit does not shut down due to overspeed.

[0035] Furthermore, a hardware circuit connected to two OPC solenoid valves is provided in the relay cabinet, each relay is connected to the hardware circuit, and the OPC signal controls the two OPC solenoid valves through the hardware circuit.

[0036] S4: Multiple groups of OPC signals are respectively transmitted to the turbine auxiliary system after being expanded by the relay; in this embodiment, the turbine auxiliary system refers to the process system where the auxiliary equipment related to the operation of the turbine body is located, such as: main steam system, steam-water reheat system, condensate system, feed water system, etc.

[0037] S5: After the steam turbine auxiliary system receives the OPC signal, the OPC signal is transmitted to the heating system through a plurality of signal transmission devices connected between the steam turbine auxiliary system and the heating system;

[0038] S6: If the heating system receives at least two of the multiple groups of OPC signals, it outputs a control signal, and the control signal is used to control the shutdown of the controlled equipment between the heating system and the steam turbine auxiliary system. In the heating system, the scanning period of the OPC signal is 30 to 60 ms. And the controlled equipment includes a regulating steam valve and a steam extraction check valve connected between the heating system and the steam turbine auxiliary system. After the OPC signal is triggered, the high-pressure regulating and medium-pressure regulating steam valves of the steam turbine generator set are closed, the steam extraction check valve protection of each stage of the steam turbine is closed, and the steam turbine heating circuit is cut off.

[0039] If the signal to start the system does not work when the unit is shedding load, the unit will shut down due to overspeed. More importantly, this may cause power outages and heat interruptions. If the OPC signal transmission is unreliable or has a large delay, it may cause the heating circuit to reflux, causing the turbine to overspeed, which will cause great harm to equipment operation and personal safety. Therefore, the OPC signal must be highly reliable and fast.

[0040] Furthermore, the signal transmission device is also connected between the heating system and the controlled device, and the control signal is transmitted through the signal transmission device. The signal transmission device includes a connection terminal and a cable connected to the connection terminal. The turbine auxiliary system is equipped with a plurality of input connection terminals DI and a corresponding number of output connection terminals DO, the heating system is equipped with a plurality of input connection terminals DI connected one-to-one with the output connection terminals DO on the turbine auxiliary system, and the heating system is also equipped with an output connection terminal DO.

[0041] Under the condition that the control system architecture remains unchanged, since the relay cabinet and the turbine auxiliary system have signal interlocks with the OPC solenoid valve and the check valves of the exhaust pipes at all levels of the turbine, and considering that it will not affect the safety protection circuit, the front-end signals of the relay cabinet and the turbine auxiliary system are not changed. Therefore, the OPC signal is divided into multiple channels and sent from different output connection terminals DO of the turbine auxiliary system to the heating system. At the same time, the scanning cycle of the OPC signal in the heating system is reduced, such as 50ms, to ensure that the response time of the adjusted OPC signal is shortened, so that the overall response time is shortened, which can meet the control requirements of the controlled equipment and run more safely.

[0042] In a specific embodiment of the present invention, three groups of OPC signals, namely OPC-1, OPC-2 and OPC-3, are transmitted to the heating system through three groups of transmission routes, and one OPC signal is output after three-out-of-two logic in the heating system controller to control the corresponding device action. The entire signal transmission process adopts a hard wiring method, which can improve signal reliability, avoid the response time of CPU processing during communication transmission, and improve the safety of nuclear power unit operation under heating conditions.

[0043] like Figure 1 The signal transmission flow chart of the nuclear energy heating system shown in the figure, the present invention also discloses a nuclear energy heating system, comprising a first controller, a second controller and a plurality of signal transmission devices arranged between the first controller and the second controller; wherein the first controller is located in a steam turbine auxiliary system in a nuclear energy power generation system, and is used to send the received OPC signal to the second controller through the plurality of signal transmission devices respectively;

[0044] The second controller is located in the heating system and is used to receive OPC signals. If at least two of the multiple groups of OPC signals are received, a control signal is output. The control signal is used to control the shutdown of the controlled equipment between the heating system and the steam turbine auxiliary system, thereby cutting off the heating circuit between the heating system and the steam turbine generator set to prevent steam from flowing back into the steam turbine generator set and causing a safety accident.

[0045] See also Figure 1 The nuclear energy heating system further includes a third controller, which is located in the overspeed protection control system. The third controller is used to generate an OPC signal by monitoring the operating state of the steam turbine and output it to the first controller. Specifically, the third controller is a controller in the overspeed protection control system, which is used to monitor the operating state of the steam turbine generator set and trigger the overspeed protection control system to generate multiple groups of OPC signals when the steam turbine generator set is in load rejection operation.

[0046] In this embodiment, the third controller is a controller in a conventional overspeed protection control system, which is a link in the control system architecture of the nuclear power generation system and is used for steam turbine monitoring, i.e., steam turbine trip protection. When the steam turbine generator set suddenly sheds load, the electric overspeed solenoid valve in the steam turbine protection system receives the load shedding signal, the solenoid valve is actuated, the pressure oil and return oil are connected, and the high-pressure speed regulating valve is quickly closed to ensure that the unit does not shut down due to overspeed.

[0047] See also Figure 1 The nuclear energy heating system also includes a relay cabinet, which includes a plurality of relays corresponding to the plurality of OPC signals. The signals returned from the field are isolated to avoid interference with the controller, and the signals are transmitted to the controller after isolation. The relay is used to receive the plurality of OPC signals output by the third controller, and transmit them to the first controller after expansion. The relay is also used to control the connection of the pressure oil and the return oil according to the OPC signal, and to reduce the high-pressure speed regulating valve.

[0048] Furthermore, the scanning period of the OPC signal in the second controller is 30-60ms, which can be adjusted by those skilled in the art according to the actual situation. Specifically, the implementation process of this embodiment is detailed in the implementation process of the corresponding steps in the above-mentioned overspeed protection control signal transmission method embodiment, which will not be repeated here.

[0049] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for transmitting an overspeed protection control signal of a nuclear energy heating system, characterized in that: include: After the steam turbine auxiliary system receives the overspeed protection control signal, it transmits it to the heating system through a plurality of signal transmission devices connected between the steam turbine auxiliary system and the heating system; If the heating system receives at least two of the multiple groups of overspeed protection control signals, it outputs a control signal, wherein the control signal is used to control the shutdown of the controlled equipment between the heating system and the steam turbine auxiliary system; Before the steam turbine auxiliary system receives the overspeed protection control signal, it also includes: When the steam turbine generator set is in load rejection operation, the overspeed protection control system is triggered to generate a plurality of groups of overspeed protection control signals; A plurality of groups of the overspeed protection control signals are transmitted to the relay; The relay controls the connection of the pressure oil and the return oil according to the overspeed protection control signal, and adjusts the high-pressure speed regulating valve; A plurality of groups of overspeed protection control signals are respectively transmitted to the steam turbine auxiliary system after being expanded by the relay.

2. The overspeed protection control signal transmission method of the nuclear energy heating system according to claim 1 is characterized in that: In the heating system, the scanning period of the overspeed protection control signal is 30-60ms.

3. The overspeed protection control signal transmission method of the nuclear energy heating system according to claim 1 is characterized in that: The controlled equipment includes a regulating steam valve and a steam extraction check valve connected between the heating system and the steam turbine auxiliary system.

4. The overspeed protection control signal transmission method for a nuclear energy heating system according to any one of claims 1 to 3, characterized in that: The signal transmission device is also connected between the heating system and the controlled device, and the control signal is transmitted through the signal transmission device; The signal transmission device includes a connection terminal and a cable connected to the connection terminal.

5. A nuclear energy heating system, characterized in that: It includes a first controller, a second controller, a third controller, a relay cabinet, and a plurality of signal transmission devices arranged between the first controller and the second controller; The first controller is located in a steam turbine auxiliary system in a nuclear power generation system, and is used to send the received overspeed protection control signal to the second controller through a plurality of groups of the signal transmission devices; The second controller is located in the heating system and is used to receive the overspeed protection control signal. If at least two of the multiple groups of overspeed protection control signals are received, the second controller outputs a control signal, which is used to control the shutdown of the controlled equipment between the heating system and the steam turbine auxiliary system; The third controller is located in the overspeed protection control system and is used to trigger the overspeed protection control system to generate and output multiple groups of overspeed protection control signals when the steam turbine generator set is in load rejection operation; The relay cabinet includes a plurality of relays corresponding one to one with the plurality of groups of overspeed protection control signals. The relays are used to receive the plurality of groups of overspeed protection control signals output by the third controller, and transmit them to the first controller after expansion. The relays are also used to control the connection of pressure oil and return oil according to the overspeed protection control signals, and to reduce the high-pressure speed regulating valve.

6. The nuclear energy heating system according to claim 5, characterized in that: In the second controller, the scanning period of the overspeed protection control signal is 30-60ms.

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