Anti-interference method for gas turbine island mode rotating speed YSIL card

Abstract

The invention relates to an anti-interference method for a gas turbine island mode rotating speed YSIL card. The anti-interference method comprises the following steps: step 1, constructing an anti-interference buffer loop on an interference source channel; and step 2, connecting the anti-interference buffer loops constructed in the step 1 in parallel in a plurality of drain gate channels causing the rotating speed interference of the YSIL clamping piece respectively. The problem that a rotating speed YSIL clamping piece is prone to being interfered can be solved.

Description

Technical Field

[0001] The invention belongs to the technical field of gas turbine power plants, and relates to an anti-interference method for a speed YSIL card, in particular to an anti-interference method for a speed YSIL card in an island mode of a gas turbine. Background Art

[0002] In power plants, whether the DCS system is safe and reliable directly affects the safe and stable operation of the entire unit. Among the many factors that affect the stability of DCS, signal interference is one of the most frequent and influential factors. Therefore, how to improve the anti-interference ability of DCS and eliminate signal interference as much as possible is of great significance in the actual production of power plants.

[0003] During the operation of the gas-steam combined cycle unit, it was found that its speed YSIL card was particularly susceptible to interference, especially when the unit was connected to the grid or when the load fluctuated greatly. The speed signal was extremely susceptible to interference, and the signal soared beyond the trip protection setting, causing the unit to trip. We used traditional anti-interference methods to check various factors such as grounding method, cable laying layout and type, communication network cable model, speed probe installation gap, etc., adjusted the grounding cable laying method, re-laid special multi-strand speed cable, upgraded the communication network cable from Category 5 to Category 6, and installed EMI anti-interference magnetic rings at the cable heads, re-installed the speed probe, and reduced the probe gap, etc., but none of them solved the anti-interference problem of the YSIL card.

[0004] Since the FCB island operation mode of the gas turbine will suddenly throw off the grid load and operate independently with the factory power, the load fluctuation is extremely large, and the requirements for speed accuracy are quite strict. Therefore, in order to realize the FCB island operation of the gas turbine, it is urgent to find a solution to the problem of speed YSIL card interference.

[0005] After searching, no published technical documents identical or similar to the present invention were found. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and to propose an anti-interference method for a speed YSIL card of a gas turbine in island mode, which can solve the problem that the speed YSIL card is easily interfered with.

[0007] The present invention solves the practical problem by adopting the following technical solutions:

[0008] An anti-interference method for a YSIL card for a gas turbine island mode speed includes the following steps:

[0009] Step 1: Build an anti-interference buffer loop on the interference source channel;

[0010] Step 2: connect the anti-interference buffer circuit constructed in step 1 in parallel in multiple drain gate channels that cause YSIL card speed interference.

[0011] Moreover, the specific method of step 1 is:

[0012] An anti-interference buffer circuit is constructed on the interference source channel, and the anti-interference buffer circuit includes: an arc-extinguishing resistor-capacitor absorber and a varistor; the arc-extinguishing resistor-capacitor absorber and the varistor are respectively connected in parallel to the valve coil.

[0013] Furthermore, the arc-extinguishing RC absorber and the varistor are respectively connected in parallel to the valve coil via a terminal block.

[0014] Moreover, the specific method of step 2 is:

[0015] The anti-interference buffer circuit is connected to the shaft seal balance pipe drain valve, the medium-pressure cylinder last-stage drain valve, the high-pressure cylinder body drain valve, the high-pressure main steam valve rear drain valve, the medium-pressure cylinder body drain valve, the medium-pressure balance pipe drain valve, and the medium-pressure main steam valve rear drain valve respectively.

[0016] Moreover, the RC arc-extinguishing resistor-capacitor absorber C adopts a 0.1UF, 600V+100R / 2W model; the varistor R adopts a V250LA2P model.

[0017] Advantages and beneficial effects of the present invention:

[0018] 1. Aiming at the problem that the speed YSIL card is easily interfered with, the present invention proposes an anti-interference method for the speed YSIL card in the island mode of the gas turbine, which is suitable for preventing the speed from overspeeding during the island operation of the gas turbine FCB. The present invention reduces the interference source signal by connecting the buffer circuit in parallel to the valve coil, thereby solving the problem that the universal YSIL card of the 9H gas turbine is interfered with, causing the speed to soar, triggering the machine trip protection, and failing to smoothly realize the FCB island operation.

[0019] 2. The present invention is an anti-interference method for the YSIL card of the island mode speed of the gas turbine. Since the DCS control system is a whole, each board shares a set of system power supply. Under a certain special working condition, it is possible to generate inductive load voltage fluctuations, causing interference between signals. To this end, the present invention proposes a buffer circuit to achieve the effect of surge suppression. The present invention first finds out the direct interference source that causes signal interference when the special working condition changes in the 9H type gas turbine control system, and designs a buffer circuit in the interference source channel, using anti-interference arc-extinguishing resistor-capacitor absorber and varistor to consume the energy generated by the self-inductance potential, reduce the damage of the arc to the node, and reduce the interference source signal. Finally, an interference test is performed, and the arc-extinguishing resistor-capacitor absorber and varistor models are matched according to the test results, and the interference problem of the YSIL card is finally solved. The present invention has the characteristics of simple operation, low cost and precise anti-interference.

[0020] 3. In addition to being applicable to the YSIL card of the gas turbine speed, the present invention also has a positive effect in other interference circuits caused by voltage signal fluctuations and has promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of an anti-interference buffer circuit modified on an interference source channel of the present invention;

[0022] Figure 2 is a schematic diagram of impedance coupling of a common power line of the present invention;

[0023] Figure 3 is a schematic diagram of a buffer circuit of the present invention;

[0024] Figure 4 It is a decomposition schematic diagram of the unidirectional pulsating voltage of the present invention;

[0025] FIG5( a ) is a schematic diagram of a capacitor filter - an output circuit of a rectifier circuit according to the present invention;

[0026] FIG5( b ) is a capacitor filtering principle diagram of the present invention - a capacitor filtering circuit.

[0027] Description of reference numerals:

[0028] 1-arc quenching RC absorber; 2-varistor; 3-valve coil; 4-terminal block. DETAILED DESCRIPTION

[0029] The embodiments of the present invention are further described in detail below with reference to the accompanying drawings:

[0030] An anti-interference method for a YSIL card for a gas turbine island mode speed includes the following steps:

[0031] Step 1: When the unit FCB is running, the seven steam traps of the turbine body are opened almost simultaneously. When the valve coil loses power, a large back-electromotive force voltage spike will be generated, and these voltage spikes will be reflected on the DC power supply.

[0032] Therefore, the present invention constructs an anti-interference buffer circuit on the channels of these valve coils, that is, on the interference source channels;

[0033] like Figure 1 As shown, the specific method of step 1 is:

[0034] The anti-interference buffer circuit comprises: an arc-extinguishing RC absorber and a varistor; the arc-extinguishing RC absorber and the varistor are respectively connected in parallel to the valve coil.

[0035] In this embodiment, the arc-extinguishing RC absorber and the varistor are respectively connected in parallel to the valve coil via a terminal block.

[0036] Step 2, connecting the anti-interference buffer circuit constructed in step 1 in parallel in multiple drain gate channels that cause the YSIL card speed interference;

[0037] The specific method of step 2 is:

[0038] The anti-interference buffer circuit is connected to the shaft seal balance pipe drain valve, the intermediate pressure cylinder final stage drain valve, the high pressure cylinder body drain valve, the high pressure main steam valve rear drain valve, the intermediate pressure cylinder body drain valve, the intermediate pressure balance pipe drain valve, and the intermediate pressure main steam valve rear drain valve respectively;

[0039] The RC arc-extinguishing resistor-capacitor absorber C adopts the model of 0.1UF, 600V+100R / 2W; the varistor R adopts the model of V250LA2P;

[0040] The working principle of the present invention is:

[0041] 1. Cause Analysis

[0042] The sources of interference in the DCS system are multifaceted and even complicated. Interference comes from both outside and inside the system. External interference has nothing to do with the system structure and is only determined by external environmental factors such as usage conditions. Internal interference is caused by the system structure layout and manufacturing process. No matter what type of interference, it will always enter the DCS system in some way. The main ways of interference propagation are electrostatic coupling, magnetic field coupling and common impedance coupling. Through elimination and analysis, the present invention determines that the way to cause the speed YSIL card to be interfered is common impedance coupling.

[0043] Common impedance coupling occurs when the currents of two circuits flow through a common impedance, and the voltage drop of one circuit across the impedance affects the other circuit, resulting in mutual interference.

[0044] Figure 2 The figure is a schematic diagram of impedance coupling of a common power line. On a module circuit board, operational amplifiers A1 and A2 are two independent loops, but they are connected to a common voltage Ue. The equivalent resistances R1 and R2 of the power return line are the common impedance of the two loops. When the current i1 changes, the voltage drop change on R1 and R2 will affect the current i2 of another loop.

[0045] 2. On-site investigation

[0046] By investigating the actual situation on site, the present invention found that when the unit is connected to the grid and the load fluctuates, the seven drain doors of the main body are opened almost at the same time, namely, the shaft seal balance pipe drain door, the medium pressure cylinder final stage drain door, the high pressure cylinder body drain door, the high pressure main steam valve rear drain door, the medium pressure cylinder body drain door, the medium pressure balance pipe drain door, and the medium pressure main steam valve rear drain door. The simultaneous opening of these seven doors will cause strong interference, resulting in large fluctuations in the DCS system loop voltage and causing YSIL card speed interference.

[0047] 3. Solution

[0048] To address this issue, we will Figure 1 The anti-interference buffer circuits are connected in parallel to the seven drain gate channels, and the seven buffer circuits work together to suppress signal interference. Figure 3 As shown, (RC arc-extinguishing resistor-capacitor absorber C adopts 0.1UF, 600V+100R / 2W model, and varistor R adopts V250LA2P model, these models can meet the voltage level required on site)

[0049] 4. Effect inspection

[0050] After the implementation of the solution, we found that the interference problem of YSIL card components was solved through intercom interference test, unit lock-up test, and brake-open test. The speed no longer rises abnormally at the moment of grid connection or load fluctuation, laying the foundation for the island operation of 9H gas turbine FCB of our company, thus ensuring the successful realization of the island operation of 9H gas turbine FCB.

[0051] The anti-interference working principle of the arc-extinguishing RC absorber of the present invention is:

[0052] 1) Unidirectional pulsating DC voltage waveform, such as Figure 4 As shown in the figure, it can be seen that the direction of the voltage is consistent at any time, but the voltage amplitude fluctuates, that is, on the time axis, the voltage shows periodic changes, so it is pulsating.

[0053] 2) However, according to the waveform decomposition principle, this voltage can be decomposed into a DC voltage and a group of AC voltages with different frequencies. The dotted line part is the DC component of the unidirectional pulsating DC voltage U., and the solid line part is the AC component in UO.

[0054] 3) According to the above analysis, since the unidirectional pulsating DC voltage can be decomposed into AC and DC, in the filter circuit of the power supply circuit, the AC component in the voltage can be filtered out by using the characteristics of "isolating DC and passing AC" and energy storage of the capacitor, or by using the characteristics of "isolating AC and passing DC" of the inductor. Figure (5) shows the principle diagram of capacitor filtering.

[0055] 4) Figure 5(a) shows the output circuit of the rectifier circuit. After the AC voltage passes through the rectifier circuit, the output is unidirectional pulsating DC, which is UO in the circuit.

[0056] 5) Figure 5(b) is a capacitor filter circuit. Since capacitor C1 is equivalent to an open circuit for DC power, the DC voltage output by the rectifier circuit cannot pass through C1 to the ground, but can only be added to the load RL (RL in the figure). For the AC component output by the rectifier circuit, since C1 has a large capacity and a small capacitive reactance, the AC component flows to the ground through C1 and cannot be added to the load RL. In this way, the required DC voltage +U is extracted from the unidirectional pulsating DC power through the filtering of capacitor C1. The larger the capacity of the filter capacitor C1, the smaller the capacitive reactance to the AC component, which makes the AC component remaining on the load RL smaller and the filtering effect better.

[0057] The anti-interference working principle of the varistor of the present invention is:

[0058] The biggest feature of a varistor is that when the voltage applied to it is lower than its threshold value "UN", the current flowing through it is extremely small, which is equivalent to a closed valve. When the voltage exceeds UN, the current flowing through it surges, which is equivalent to the valve opening. By using this function, voltage clamping is performed when the circuit is subjected to overvoltage, absorbing excess current to protect sensitive devices, and suppressing abnormal overvoltages that often occur in the circuit, protecting the circuit from damage caused by overvoltage.

[0059] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0060] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0061] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0062] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

Claims

1. An anti-interference method for a YSIL card for a gas turbine island mode speed, characterized in that: The following steps are involved: Step 1: Build an anti-interference buffer loop on the interference source channel; Step 2: connect the anti-interference buffer circuit constructed in step 1 in parallel in multiple drain gate channels that cause YSIL card speed interference.

2. The anti-interference method for the YSIL card of the island mode speed of the gas turbine according to claim 1 is characterized by: The specific method of step 1 is: An anti-interference buffer circuit is constructed on the interference source channel, and the anti-interference buffer circuit includes: an arc-extinguishing resistor-capacitor absorber and a varistor; the arc-extinguishing resistor-capacitor absorber and the varistor are respectively connected in parallel to the valve coil.

3. The anti-interference method for the YSIL card of the island mode speed of the gas turbine according to claim 2 is characterized in that: The arc-extinguishing RC absorber and the varistor are respectively connected in parallel to the valve coil through a terminal block.

4. The anti-interference method for the YSIL card of the island mode speed of the gas turbine according to claim 1 is characterized in that: The specific method of step 2 is: The anti-interference buffer circuit is connected to the shaft seal balance pipe drain valve, the medium-pressure cylinder last-stage drain valve, the high-pressure cylinder body drain valve, the high-pressure main steam valve rear drain valve, the medium-pressure cylinder body drain valve, the medium-pressure balance pipe drain valve, and the medium-pressure main steam valve rear drain valve respectively.

5. The anti-interference method for the YSIL card of the island mode speed of the gas turbine according to claim 2 is characterized in that: The arc-extinguishing RC absorber C adopts 0.1UF, 600V+100R / 2W model; The varistor R is model V250LA2P.

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