Control method of oil purification device

Abstract

The invention discloses a control method of an oil purification device, which comprises the following steps: when the oil purification device is in an input state, acquiring a liquid level value and a vacuum value of the oil purification device; according to the liquid level value and first preset control logic, the liquid level fault type of the oil purification device is determined; determining a liquid level monitoring fault signal value according to the liquid level fault type; and according to the liquid level monitoring fault signal value, the vacuum value, the liquid level value, the preset liquid level value and the preset vacuum value, linkage start and stop of the vacuum pump, the oil inlet pump, the oil drain pump and the oil inlet electromagnetic valve are controlled respectively. According to the technical scheme provided by the embodiment of the invention, the technical problems that the control mode, vacuum and liquid level measurement of an existing oil purification device are inaccurate, oil inlet damage of a vacuum pump occurs many times, and unsafe incidents of on-site oil injection are caused are solved, and the vacuum and liquid level measurement accuracy and the system operation reliability and safety are improved.

Description

Technical Field

[0001] The invention relates to the technical field of control of lubricating oil system of steam turbine in thermal power plant, and in particular to a control method of an oil purification device. Background Art

[0002] The oil purification device of a thermal power plant is a lubricating oil filtration system under vacuum environment. Generally, the liquid level switch is used for alarm and interlocking the start and stop of the oil inlet pump and the oil discharge pump. After a long period of operation, once the oil inlet pump, the oil discharge pump, the liquid level switch or the motor fails, it is very easy to cause the oil storage tank of the oil purification device to be full of oil, which is discharged through the vacuum pump, causing the lubricating oil level of the steam turbine to be low, causing the steam turbine to trip and fire accidents.

[0003] The control method of the existing oil purification device, the inaccurate vacuum and liquid level measurement, has led to multiple oil inlet damage to the vacuum pump, causing unsafe incidents of on-site oil injection. Summary of the invention

[0004] The present invention provides a control method for an oil purification device to solve the technical problems that the control mode of the existing oil purification device causes inaccurate vacuum and liquid level measurement, resulting in multiple oil inlet damage to the vacuum pump and causing unsafe incidents of on-site oil injection.

[0005] According to one aspect of the present invention, there is provided a control method for an oil purification device, comprising:

[0006] When the oil purification device is in operation, obtain the liquid level value and vacuum value of the oil purification device;

[0007] Determining a liquid level fault type of the oil purification device according to the liquid level value and a first preset control logic;

[0008] Determining a liquid level monitoring fault signal value according to the liquid level fault type;

[0009] According to the liquid level monitoring fault signal value, the vacuum value, the liquid level value, the preset liquid level value and the preset vacuum value, the interlocking start and stop of the vacuum pump, the oil inlet pump, the oil discharge pump and the oil inlet solenoid valve are controlled respectively.

[0010] Optionally, determining the liquid level fault type of the oil purification device according to the liquid level value and the first preset control logic includes:

[0011] determining a liquid level signal of the oil purification device according to the liquid level value and a first preset control logic;

[0012] The liquid level fault type of the oil purification device is determined according to the liquid level signal and the second preset control logic.

[0013] Optionally, determining the liquid level signal of the oil purification device according to the liquid level value and the first preset control logic includes:

[0014] If the liquid level value is greater than the preset upper limit of the range after the first preset delay time, or if the liquid level value is less than the preset lower limit of the range after the first preset delay time, a first liquid level signal is output;

[0015] If the liquid level value is greater than the preset alarm upper limit after the first preset delay time, or if the liquid level value is less than the preset alarm lower limit after the first preset delay time, a second liquid level signal is output;

[0016] If the rising rate calculated according to the liquid level value is greater than the first preset range percentage after the first preset delay time, or if the falling rate calculated according to the liquid level value is greater than the first preset range percentage after the first preset delay time, then a third liquid level signal is output;

[0017] If the change rate calculated according to the liquid level value is less than the second preset range percentage after the second preset delay time, a fourth liquid level signal is output.

[0018] Optionally, determining the type of liquid level fault of the oil purification device according to the liquid level signal and the second preset control logic includes:

[0019] If the first liquid level signal is output and the liquid level value does not satisfy the condition of being less than the preset upper limit of the measuring range and greater than the preset lower limit of the measuring range after the third preset delay time, it is determined that the liquid level fault type of the oil purification device is a liquid level measurement error;

[0020] If the second liquid level signal is output and the liquid level value does not satisfy the condition that it is less than the preset alarm upper limit and greater than the preset alarm lower limit after the third preset delay time, it is determined that the liquid level fault type of the oil purification device is liquid level overlimit;

[0021] If the third liquid level signal is output and the rising rate / falling rate calculated according to the liquid level value does not satisfy the first preset range percentage after the third preset delay time, it is determined that the liquid level fault type of the oil purification device is a large liquid level change rate;

[0022] If the fourth liquid level signal is output and the change rate calculated according to the liquid level value does not satisfy the second preset range percentage after the fourth preset delay time, the liquid level fault type of the oil purification device is determined to be no change in liquid level.

[0023] Optionally, determining the liquid level monitoring fault signal value according to the liquid level fault type includes:

[0024] If the liquid level fault type is one of the liquid level measurement error, the liquid level exceeding the limit, the liquid level changing rate being large, and the liquid level not changing, and the oil purification device is in the operation state, then the liquid level monitoring fault signal value is determined to be 1.

[0025] Optionally, the preset liquid level value includes a first preset liquid level value, a second preset liquid level value, a third preset liquid level value, a fourth preset liquid level value and a fifth preset liquid level value, and the preset vacuum value includes a first preset vacuum value and a second preset vacuum value;

[0026] The interlocking start and stop of the vacuum pump, the oil inlet pump, the oil discharge pump and the oil inlet solenoid valve are controlled respectively according to the liquid level monitoring fault signal value, the vacuum value, the liquid level value, the preset liquid level value and the preset vacuum value, including:

[0027] When the oil purification device is in operation, the interlocking start and stop of the vacuum pump is controlled according to the liquid level monitoring fault signal value, the vacuum value, the liquid level value, the first preset vacuum value, the second preset vacuum value and the first preset liquid level value;

[0028] When the oil purification device is in the operation state, the interlocking start and stop of the oil feed pump is controlled according to the liquid level monitoring fault signal value, the liquid level value, the second preset liquid level value and the third preset liquid level value;

[0029] When the oil purification device is in the operation state, the interlocking start and stop of the oil discharge pump is controlled according to the liquid level monitoring fault signal value, the liquid level value, the fourth preset liquid level value and the fifth preset liquid level value;

[0030] When the oil purification device is in the operating state, the interlocking start and stop of the oil inlet solenoid valve is controlled according to the liquid level monitoring fault signal value, the liquid level value and the fourth preset liquid level value.

[0031] Optionally, when the oil purification device is in the operation state, controlling the interlocking start and stop of the vacuum pump according to the liquid level monitoring fault signal value, the vacuum value, the liquid level value, the first preset vacuum value, the second preset vacuum value and the first preset liquid level value includes:

[0032] When the liquid level monitoring fault signal value is 0 and the liquid level value is less than the first preset liquid level value, a first result is obtained through a "not" logic;

[0033] When the liquid level monitoring fault signal value is 0, a second result is obtained through a "not" logic;

[0034] The second result and the liquid level value greater than the first preset liquid level value are subjected to an “AND” logic to obtain a third result;

[0035] When the oil purification device is in the operation state, the vacuum value is greater than the first preset vacuum value, and the first result and the third result are met, the vacuum pump is started in a chain manner;

[0036] When the oil purification device is in the operation state and the vacuum value is less than the second preset vacuum value, the fourth result is obtained;

[0037] When the liquid level monitoring fault signal value is 1, or the liquid level value is greater than the first preset liquid level value, it is the fifth result;

[0038] When the liquid level monitoring fault signal value is 0 and after the “not” logic, and the liquid level value is greater than the first preset liquid level value, after the “and” logic, a sixth result is obtained;

[0039] If any one of the fourth result, the fifth result and the sixth result occurs, the vacuum pump is stopped in a chain reaction.

[0040] Optionally, when the oil purification device is in the operation state, controlling the interlocking start and stop of the oil feed pump according to the liquid level monitoring fault signal value, the liquid level value, the second preset liquid level value and the third preset liquid level value comprises:

[0041] When the liquid level monitoring fault signal value is 0 and after the “not” logic, and the liquid level value is less than the second preset liquid level value, after the “and” logic, a seventh result is obtained;

[0042] The seventh result and the liquid level value being less than the second preset liquid level value are subjected to an “OR” logic to obtain an eighth result;

[0043] When the oil purification device is in operation and the eighth result is satisfied, the oil inlet pump is started in a chain manner;

[0044] When the liquid level monitoring fault signal value is 0 and after the “not” logic, and the liquid level value is greater than the third preset liquid level value, after the “and” logic, a ninth result is obtained;

[0045] The ninth result and the liquid level value greater than the third preset liquid level value are subjected to an “OR” logic to obtain a tenth result;

[0046] When the oil purification device is in the operation state and the tenth result is satisfied, the oil inlet pump is stopped interlockedly.

[0047] Optionally, when the oil purification device is in the operation state, controlling the interlocked start and stop of the oil discharge pump according to the liquid level monitoring fault signal value, the liquid level value, the fourth preset liquid level value and the fifth preset liquid level value comprises:

[0048] When the liquid level monitoring fault signal value is 0 and after the “not” logic, and the liquid level value is greater than the fourth preset liquid level value, after the “and” logic, an eleventh result is obtained;

[0049] The eleventh result and the liquid level value being greater than the fourth preset liquid level value are subjected to an “OR” logic to obtain a twelfth result;

[0050] When the oil purification device is in operation and the twelfth result is satisfied, the oil discharge pump is started in a chain manner;

[0051] When the liquid level monitoring fault signal value is 0 and after the “not” logic, and the liquid level value is less than the fifth preset liquid level value, after the “and” logic, a thirteenth result is obtained;

[0052] The thirteenth result and the liquid level value being less than the fifth preset liquid level value are subjected to an “OR” logic to obtain a fourteenth result;

[0053] When the oil purification device is in the activated state and the fourteenth result is satisfied, the oil discharge pump is stopped in an interlocked manner.

[0054] Optionally, when the oil purification device is in the operation state, controlling the interlocking start and stop of the oil inlet solenoid valve according to the liquid level monitoring fault signal value, the liquid level value and the fourth preset liquid level value comprises:

[0055] When the liquid level monitoring fault signal value is 0 and after the "not" logic, the fifteenth result is obtained;

[0056] The fifteenth result, the oil purification device being in the operating state, and the liquid level value being greater than the fourth preset liquid level value are subjected to an “AND” logic to obtain a sixteenth result;

[0057] When the oil purification device is in the operation state and the sixteenth result is not satisfied, the oil inlet solenoid valve is controlled to be opened;

[0058] When the oil purification device is in the exit state and the sixteenth result is satisfied, the oil inlet solenoid valve is controlled to be closed.

[0059] A control method for an oil purification device provided in an embodiment of the present invention includes obtaining a liquid level value and a vacuum value of the oil purification device when the oil purification device is in an operational state; determining a liquid level fault type of the oil purification device according to the liquid level value and a first preset control logic; determining a liquid level monitoring fault signal value according to the liquid level fault type; and controlling the interlocking start and stop of a vacuum pump, an oil inlet pump, an oil discharge pump and an oil inlet solenoid valve respectively according to the liquid level monitoring fault signal value, the vacuum value, the liquid level value, the preset liquid level value and the preset vacuum value. The technical solution provided by the embodiment of the present invention, on the one hand, changes the original PLC control to DCS control in terms of hardware equipment, and cancels PLC control cards and other equipment with high environmental requirements, thereby effectively reducing the incidence of accidents; on the other hand, an analog pressure transmitter, an analog liquid level transmitter and a magnetic liquid level switch are used to obtain the liquid level value and vacuum value of the oil purification device, and combined with the first preset control logic, the interlocking start and stop of the vacuum pump, the oil inlet pump, the oil discharge pump and the oil inlet solenoid valve are controlled respectively, so as to realize real-time monitoring and prediction of the liquid level and vacuum of the oil purification device, effectively avoiding the problem of turbine tripping and fire accidents caused by low turbine lubricating oil level due to inaccurate vacuum and liquid level measurement, thereby improving the accuracy of vacuum and liquid level measurement and the reliability and safety of system operation.

[0060] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0062] Figure 1 A flow chart of a control method for an oil purification device provided by an embodiment of the present invention;

[0063] Figure 2 A control logic diagram for selecting an oil purification device provided in an embodiment of the present invention;

[0064] Figure 3 A logic diagram for determining a liquid level signal provided in an embodiment of the present invention;

[0065] Figure 4 An output logic diagram of a liquid level fault type provided by an embodiment of the present invention that is a liquid level measurement error;

[0066] Figure 5An output logic diagram of a liquid level fault type of liquid level exceeding a limit provided in an embodiment of the present invention;

[0067] Figure 6 An output logic diagram for a liquid level fault type of a large liquid level change rate provided in an embodiment of the present invention;

[0068] Figure 7 An output logic diagram of a liquid level fault type of no change in liquid level provided in an embodiment of the present invention;

[0069] Figure 8 A control logic diagram of a chained start vacuum pump provided in an embodiment of the present invention;

[0070] Fig. 9 A control logic diagram of the interlocked stop vacuum pump provided in an embodiment of the present invention;

[0071] Fig.10 A control logic diagram of the interlocked start oil inlet pump provided in an embodiment of the present invention;

[0072] Fig.11 A control logic diagram of the interlocked stop of the oil inlet pump provided in an embodiment of the present invention;

[0073] Fig.12 A control logic diagram of the interlocked start-up of the oil drain pump provided by an embodiment of the present invention;

[0074] Fig.13 A control logic diagram of the interlocked stop of the oil drain pump provided by an embodiment of the present invention;

[0075] Fig.14 A control logic diagram of an interlocked start-stop oil inlet solenoid valve provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0076] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme 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 only 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 should fall within the scope of protection of the present invention.

[0077] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0078] As an important auxiliary equipment of the steam turbine lubricating oil system, the existing structure of the oil purification device is mainly composed of a vacuum system, a filtration system, a monitoring system, an oil delivery system, etc. The vacuum system consists of a vacuum pump, a vacuum degassing tank, a vacuum gauge, an exhaust solenoid valve, a gas-water separator, etc.; the filtration system consists of a coarse filter, a demulsifier, a polymer separator, a fine filter, etc.; the monitoring system consists of an electric control cabinet with a programmable logic controller (PLC), a vacuum monitoring instrument (electric contact pressure gauge), a liquid level monitoring instrument (high liquid level switch and low liquid level switch), a pressure monitoring instrument (on-site pressure gauge), a temperature monitoring instrument (temperature switch), etc.; the oil delivery system consists of an oil inlet pump, an oil discharge pump, an oil inlet solenoid valve and system pipelines. Working principle: The oil purification device is connected to the power supply, and the operator manually turns on the vacuum pump. After running for a certain period of time, the vacuum in the vacuum tank reaches the specified value (-60KPa), and the vacuum monitoring instrument (electric contact pressure gauge, set value -40KPa and -60KPa) sends a signal to the PLC, automatically maintaining the vacuum between (-60KPa ~ -40KPa). The PLC automatically sends a signal to the oil inlet solenoid valve, the oil inlet solenoid valve opens the oil into the equipment, and the PLC automatically starts the oil inlet pump according to the signal of the liquid level monitoring instrument (low liquid level switch). When the signal of the liquid level monitoring instrument (high liquid level switch) is triggered, the oil inlet pump is automatically stopped and the oil discharge pump is automatically started.

[0079] As can be seen from the above, the existing oil purification device uses the liquid level switch to alarm and interlock the start and stop of the oil inlet pump and the oil discharge pump. This control method has the technical problem of inaccurate vacuum and liquid level measurement, resulting in multiple vacuum pump oil inlet damage and unsafe on-site oil injection incidents.

[0080] In order to solve the above technical problems and improve the accuracy of vacuum and liquid level measurement and the reliability and safety of system operation, the present invention improves the hardware equipment of the oil purification device and proposes a new control method for the oil purification device. The improvements of the hardware equipment are as follows:

[0081] Improvement ① The monitoring system cancels PLC and is replaced by a distributed control system (DCS);

[0082] Improvement ②Cancel the vacuum monitoring instrument (electric contact pressure gauge) and replace it with an analog pressure transmitter;

[0083] Improvement ③ The liquid level monitoring instrument (high liquid level switch and low liquid level switch) is cancelled and replaced by an analog liquid level transmitter and two liquid level switches; it should be noted that the liquid level switch here is different from the liquid level switch used in the original oil purification device. The liquid level switch used in the original oil purification device is a float type mechanical liquid level switch, which is mainly composed of a float, a connecting rod, a micro switch and other components. The float is usually a hollow sphere, which may be made of plastic, stainless steel, etc. The float is connected to the micro switch through a connecting rod. When the liquid level rises, the float will float upward due to the buoyancy of the liquid. The rise of the float will drive the connecting rod to move, causing the connecting rod to touch the micro switch; when the liquid level drops, the float loses buoyancy and sinks, and the connecting rod will move accordingly, causing the micro switch to return to its original state. The on-off state change of the micro switch can be used as a liquid level signal output to determine whether the liquid level has reached the set high liquid level or low liquid level. The liquid level switch provided in the embodiment of the present invention is a magnetic liquid level switch. The magnetic liquid level switch usually uses the interaction between a magnetic float and a reed switch to measure the liquid level. The structure is as follows: one or more reed switches are installed in a closed non-magnetic tube, and then the tube passes through one or more hollow floats with an annular magnet inside. When the liquid level in the container changes, the float moves up and down as the liquid level rises or falls. Since there is a magnet inside the float, the movement of the float will change the position of the magnet. When the magnet in the float approaches the reed switch, the magnetic field will cause the two metal reeds in the reed switch to be magnetized and attracted; when the magnet is away from the reed switch, the reed loses its magnetic effect and disconnects. Through the attraction or disconnection action of the reed switch, a switch signal can be output to reflect the change in the liquid level.

[0084] Improvement ④: Cancel the temperature monitoring instrument (temperature switch) and replace it with an analog thermal resistor.

[0085] Figure 1 A flow chart of a control method for an oil purification device provided by an embodiment of the present invention, see Figure 1 , the control method comprises:

[0086] S110. When the oil purification device is in an operational state, obtain a liquid level value and a vacuum value of the oil purification device.

[0087] Among them, since the control mode of the oil purification device is changed from local PLC to remote DCS control, in order to avoid misoperation by operators, an oil purification device startup confirmation button is added to the oil purification device DCS screen. The startup confirmation button is used to remind operators to check on-site before running the equipment; in emergency situations, in order to avoid damage to the equipment, an oil purification device emergency exit confirmation button is also added to the oil purification device DCS screen, which can exit all equipment operations of the oil purification system with one click. Its control adopts RS trigger for control, such as Figure 2 As shown, Figure 2 The oil purification device selection control logic diagram provided in the embodiment of the present invention, when S=1, R=0, the oil purification device selects the input state; when S=0, R=1, the oil purification device selects the exit state. Therefore, it is necessary to obtain the liquid level value and vacuum value of the oil purification device when the oil purification device is in the input state.

[0088] Specifically, the vacuum value of the oil purification device is measured by using a vacuum monitoring instrument in the monitoring system of the oil purification device, the original electric contact pressure gauge measurement is cancelled, and the vacuum monitoring instrument (electric contact pressure gauge) is replaced by an analog pressure transmitter; the liquid level value of the oil purification device is measured by using a liquid level monitoring instrument in the monitoring system of the oil purification device, the original liquid level monitoring instrument (high liquid level switch and low liquid level switch) measurement is cancelled, and is replaced by an analog liquid level transmitter and two magnetic liquid level switches.

[0089] S120: Determine the type of liquid level fault of the oil purification device according to the liquid level value and the first preset control logic.

[0090] The first preset control logic can be preset. The liquid level fault types include liquid level measurement error, liquid level overrun, large liquid level change rate, and no liquid level change.

[0091] Specifically, according to different measured liquid level values, in combination with the first preset control logic, different liquid level signals are output, and the liquid level fault type of the oil purification device corresponding to each liquid level signal is determined according to the different liquid level signals.

[0092] S130. Determine a liquid level monitoring fault signal value according to the liquid level fault type.

[0093] Specifically, if the liquid level fault type is one of liquid level measurement error, liquid level over limit, large liquid level change rate, and no liquid level change, and the oil purification device is in the operation state, the liquid level monitoring fault signal value is determined to be 1. Otherwise, the liquid level monitoring fault signal value is determined to be 0.

[0094] S140, according to the liquid level monitoring fault signal value, vacuum value, liquid level value, preset liquid level value and preset vacuum value, respectively control the interlocking start and stop of the vacuum pump, the oil inlet pump, the oil discharge pump and the oil inlet solenoid valve.

[0095] Specifically, according to the liquid level monitoring fault signal value, vacuum value, liquid level value, preset liquid level value and preset vacuum value, combined with different control logics, the interlocking start and stop of the vacuum pump, oil inlet pump, oil discharge pump and oil inlet solenoid valve are controlled respectively.

[0096] The technical solution provided by the embodiment of the present invention, on the one hand, changes the original PLC control to DCS control in terms of hardware equipment, and cancels PLC control cards and other equipment with high environmental requirements, thereby effectively reducing the incidence of accidents; on the other hand, an analog pressure transmitter, an analog liquid level transmitter and a magnetic liquid level switch are used to obtain the liquid level value and vacuum value of the oil purification device, and combined with the first preset control logic, the interlocking start and stop of the vacuum pump, the oil inlet pump, the oil discharge pump and the oil inlet solenoid valve are controlled respectively, so as to realize real-time monitoring and prediction of the liquid level and vacuum of the oil purification device, effectively avoiding the problem of turbine tripping and fire accidents caused by low turbine lubricating oil level due to inaccurate vacuum and liquid level measurement, thereby improving the accuracy of vacuum and liquid level measurement and the reliability and safety of system operation.

[0097] Optionally, determining the type of liquid level fault of the oil purification device according to the liquid level value and the first preset control logic includes:

[0098] A liquid level signal of the oil purification device is determined according to the liquid level value and the first preset control logic.

[0099] Specifically, Figure 3 For the liquid level signal determination logic diagram provided by the embodiment of the present invention, see Figure 3 If the liquid level value is greater than the preset upper limit of the range after the first preset delay time, or if the liquid level value is less than the preset lower limit of the range after the first preset delay time, a first liquid level signal is output.

[0100] Among them, the first preset delay time can be pre-set according to actual needs. The embodiment of the present invention illustrates the first preset delay time as 0.5 seconds as an example; the preset upper limit of the range and the preset lower limit of the range can be pre-set according to actual needs. The preset lower limit of the range and the preset upper limit of the range are usually set to 0-100%.

[0101] The output logic of the first liquid level signal is: when the acquired liquid level value is greater than the preset upper limit of the range after a delay of 0.5 seconds, or when the liquid level value is less than the preset lower limit of the range after a delay of 0.5 seconds, the first liquid level signal is output.

[0102] If the liquid level value is greater than the preset alarm upper limit after the first preset delay time, or if the liquid level value is less than the preset alarm lower limit after the first preset delay time, a second liquid level signal is output.

[0103] The preset alarm upper limit and the preset alarm lower limit can be preset according to actual needs, and the preset alarm upper limit and the preset alarm lower limit are usually set to 95%-50%.

[0104] The output logic of the second liquid level signal is: when the acquired liquid level value is greater than the preset alarm upper limit after a delay of 0.5 seconds, or when the liquid level value is less than the preset alarm lower limit after a delay of 0.5 seconds, the first liquid level signal is output.

[0105] If the rising rate calculated based on the liquid level value is greater than the first preset range percentage after the first preset delay time, or when the falling rate calculated based on the liquid level value is greater than the first preset range percentage after the first preset delay time, a third liquid level signal is output.

[0106] The first preset range percentage may be preset according to actual needs. In the embodiment of the present invention, the first preset range percentage is illustrated by taking 10% range / s as an example.

[0107] The output logic of the third liquid level signal is: when the rising rate calculated based on the liquid level value is greater than 10% of the range / s after a delay of 0.5 seconds, or when the falling rate calculated based on the liquid level value is greater than 10% of the range / s after a delay of 0.5 seconds, the third liquid level signal is output.

[0108] If the change rate calculated according to the liquid level value is less than the second preset range percentage after the second preset delay time, a fourth liquid level signal is output.

[0109] Among them, the second preset delay time and the second preset range percentage can be pre-set according to actual needs. In the embodiment of the present invention, the second preset delay time is shown as 5 seconds as an example; the second preset range percentage is shown as 1% range / s as an example.

[0110] The output logic of the fourth liquid level signal is: if the change rate calculated according to the liquid level value is less than 1% of the range / s after a delay of 5 seconds, the fourth liquid level signal is output.

[0111] The liquid level fault type of the oil purification device is determined according to the liquid level signal and the second preset control logic.

[0112] Specifically, if the first liquid level signal is output and the liquid level value does not satisfy the condition of being less than the preset range upper limit and greater than the preset range lower limit after the third preset delay time, it is determined that the liquid level fault type of the oil purification device is a liquid level measurement error.

[0113] The third preset delay time may be preset according to actual needs. In the embodiment of the present invention, the third preset delay time is illustrated by taking 3 seconds as an example.

[0114] The output logic of liquid level measurement error is as follows Figure 4 As shown, Figure 4 The output logic diagram of the liquid level fault type provided by the embodiment of the present invention is a liquid level measurement error. It can be seen from the figure that the liquid level measurement error can be output only when S=1 and R=0 are satisfied; that is, when the first liquid level signal is output, the liquid level value does not satisfy the condition of being less than the preset upper limit of the range and greater than the preset lower limit of the range after a delay of 3 seconds, that is, S=1 and R=0 are satisfied, then the liquid level fault type of the oil purification device is determined to be a liquid level measurement error. If S=0 and R=1, the liquid level measurement error is not output.

[0115] If the second liquid level signal is output and the liquid level value does not satisfy the condition of being less than the preset alarm upper limit and greater than the preset alarm lower limit after the third preset delay time, the liquid level fault type of the oil purification device is determined to be liquid level overlimit.

[0116] The output logic of liquid level exceeding limit is as follows Figure 5 As shown, Figure 5 The output logic diagram of the liquid level fault type provided by the embodiment of the present invention is the liquid level overrun. It can be seen from the figure that the liquid level overrun can be output only if S=1 and R=0 are satisfied; that is, when the second liquid level signal is output, the liquid level value does not satisfy the condition of being less than the preset alarm upper limit and greater than the preset alarm lower limit after a delay of 3 seconds, that is, S=1 and R=0 are satisfied, then the liquid level fault type of the oil purification device is determined to be the liquid level overrun. If S=0 and R=1, the liquid level overrun is not output.

[0117] If the third liquid level signal is output and the rising rate / falling rate calculated according to the liquid level value does not satisfy the first preset range percentage after the third preset delay time, it is determined that the liquid level fault type of the oil purification device is a large liquid level change rate.

[0118] The output logic of the liquid level change rate is large, such as Figure 6 As shown, Figure 6 The output logic diagram of the liquid level fault type provided by the embodiment of the present invention is a large liquid level change rate. It can be seen from the figure that the liquid level over-limit can be output only if S=1 and R=0 are satisfied; that is, when the third liquid level signal is output, the rising rate / falling rate calculated according to the liquid level value does not satisfy <10% of the range / s after the third preset delay time, that is, S=1 and R=0 are satisfied, then the liquid level fault type of the oil purification device is determined to be a large liquid level change rate. If S=0 and R=1, the large liquid level change rate is not output.

[0119] If the fourth liquid level signal is output and the change rate calculated according to the liquid level value does not satisfy the second preset range percentage after the fourth preset delay time, the liquid level fault type of the oil purification device is determined to be no change in liquid level.

[0120] The fourth preset delay time may be preset according to actual needs. In the embodiment of the present invention, the fourth preset delay time is illustrated by taking 8 seconds as an example.

[0121] The output logic of no change in liquid level is as follows Figure 7 As shown, Figure 7 The output logic diagram of the liquid level fault type provided for the embodiment of the present invention is that the liquid level does not change. It can be seen from the figure that the liquid level over-limit can be output only when S=1 and R=0 are satisfied; that is, when the fourth liquid level signal is output, the change rate calculated according to the liquid level value does not satisfy greater than>1% of the range / s after the fourth preset delay time, that is, S=1 and R=0 are satisfied, then the liquid level fault type of the oil purification device is determined to be the liquid level does not change. If S=0 and R=1, the liquid level does not change will not be output.

[0122] The first preset delay time, the second preset delay time, the third preset delay time and the fourth preset delay time may be the same or different, and the present invention is not limited to this.

[0123] Optionally, the preset liquid level value includes a first preset liquid level value, a second preset liquid level value, a third preset liquid level value, a fourth preset liquid level value and a fifth preset liquid level value, and the preset vacuum value includes a first preset vacuum value and a second preset vacuum value.

[0124] According to the liquid level monitoring fault signal value, the vacuum value, the liquid level value, the preset liquid level value and the preset vacuum value, the interlocking start and stop of the vacuum pump, the oil inlet pump, the oil discharge pump and the oil inlet solenoid valve are controlled respectively, including:

[0125] When the oil purification device is in operation, the interlocking start and stop of the vacuum pump is controlled according to the liquid level monitoring fault signal value, the vacuum value, the liquid level value, the first preset vacuum value, the second preset vacuum value and the first preset liquid level value.

[0126] Specifically, Figure 8 For the control logic diagram of the interlocked start vacuum pump provided in the embodiment of the present invention, see Figure 8 When the liquid level monitoring fault signal value is 0 and the liquid level value is less than the first preset liquid level value, a first result is obtained through the "not" logic.

[0127] The first preset liquid level value may be preset according to actual needs. In the embodiment of the present invention, the first preset liquid level value is illustrated by taking 385 mm as an example.

[0128] The first result means that the liquid level monitoring fault signal value is 0, that is, when there is no liquid level monitoring fault and the liquid level does not reach 385mm, that is, when both signal values ​​are 0, after the "not" logic, the output is 1. This result is the first result. It should be noted that 385mm here is a fixed value, and the oil purification device liquid level high switch signal has only two forms of 1 and 0, and the signal is a switch quantity.

[0129] The third result refers to the result when the second result output is 1 and the liquid level value is greater than 385 mm. Here, 385 mm is a simulation value.

[0130] When the oil purification device is in the operation state, the vacuum value is greater than the first preset vacuum value, and the first result and the third result are met, the vacuum pump is started in a chain manner.

[0131] The first preset vacuum value may be preset according to actual needs. In the embodiment of the present invention, the first preset vacuum value is illustrated by taking -30 KPa as an example.

[0132] The vacuum pump can be started in a chain only when the oil purification device is in operation and the vacuum value is greater than -30KPa and the first and third results are met.

[0133] Fig. 9 For the control logic diagram of the interlocked stop vacuum pump provided in the embodiment of the present invention, see Fig. 9 , when the oil purification device is in the put-in-place state and the vacuum value is less than the second preset vacuum value, it is the fourth result.

[0134] The second preset vacuum value can be preset according to actual needs. The embodiment of the present invention takes -60KPa as an example to illustrate the second preset vacuum value. The fourth result is that the oil purification device is in the input state, and the vacuum value is less than -60KPa, which is the result obtained by performing an "AND" logic operation on the two.

[0135] When the liquid level monitoring fault signal value is 1, or the liquid level value is greater than the first preset liquid level value, it is the fifth result.

[0136] The fifth result is the result obtained by performing an "OR" logic operation on the liquid level monitoring fault and the liquid level value>385mm. Here, 385mm is a switch value.

[0137] When the liquid level monitoring fault signal value is 0, and after the "NOT" logic, the liquid level value is greater than the first preset liquid level value, after the "AND" logic, the sixth result is obtained.

[0138] If any of the fourth result, the fifth result and the sixth result occurs, the vacuum pump will be stopped.

[0139] The control logic for interlocking the stopping of the vacuum pump and the control logic for interlocking the starting of the vacuum pump are based on the same principle, which will not be described in detail here.

[0140] When the oil purification device is in operation, the interlocking start and stop of the oil feed pump is controlled according to the liquid level monitoring fault signal value, the liquid level value, the second preset liquid level value and the third preset liquid level value.

[0141] Specifically, Fig.10 For the control logic diagram of the interlocked start oil feed pump provided by the embodiment of the present invention, see Fig.10 , when the liquid level monitoring fault signal value is 0, and after the "not" logic, the liquid level value is less than the second preset liquid level value, and after the "and" logic, the seventh result is obtained.

[0142] The second preset liquid level value is shown in the embodiment of the present invention by taking 50 mm as an example. Here, 50 mm is a simulation value.

[0143] The seventh result and the liquid level value less than the second preset liquid level value are subjected to "OR" logic to obtain the eighth result.

[0144] The second preset liquid level value 50 mm is a switch value.

[0145] When the oil purification device is in operation and the eighth result is met, the oil inlet pump is started in a chain manner.

[0146] Fig.11 For the control logic diagram of the interlocked stop of the oil feed pump provided in the embodiment of the present invention, see Fig.11 , when the liquid level monitoring fault signal value is 0, and after the "not" logic, the liquid level value is greater than the third preset liquid level value, and after the "and" logic, the ninth result is obtained.

[0147] The third preset liquid level value is shown in the embodiment of the present invention by taking 35 mm as an example. Here, 350 mm is a simulated value.

[0148] The ninth result and the liquid level value greater than the third preset liquid level value are subjected to "OR" logic to obtain the tenth result.

[0149] Among them, the third preset liquid level value 350mm here is a switch value.

[0150] When the oil purification device is in operation and the tenth result is met, the oil inlet pump is stopped interlocked.

[0151] When the oil purification device is in the operating state, the interlocking start and stop of the oil discharge pump is controlled according to the liquid level monitoring fault signal value, the liquid level value, the fourth preset liquid level value and the fifth preset liquid level value.

[0152] Specifically, Fig.12The control logic diagram of the interlocked start oil drain pump provided by the embodiment of the present invention is shown in FIG. Fig.12 , when the liquid level monitoring fault signal value is 0, and after the "not" logic, the liquid level value is greater than the fourth preset liquid level value, and after the "and" logic, the eleventh result is obtained.

[0153] The fourth preset liquid level value is shown by taking 370 mm as an example in the embodiment of the present invention, where the fourth preset liquid level value 370 mm is an analog value.

[0154] The eleventh result and the liquid level value greater than the fourth preset liquid level value are subjected to "OR" logic to obtain the twelfth result.

[0155] Among them, the fourth preset liquid level value 370mm here is a switch value.

[0156] When the oil purification device is in the operation state and the twelfth result is satisfied, the oil discharge pump is started in a chain manner.

[0157] Fig.13 The control logic diagram of the interlocked stop of the oil drain pump provided by the embodiment of the present invention is shown in FIG. Fig.13 , when the liquid level monitoring fault signal value is 0, and after the "not" logic, the liquid level value is less than the fifth preset liquid level value, and after the "and" logic, the thirteenth result is obtained.

[0158] The fifth preset liquid level value is shown as 100 mm in the embodiment of the present invention, and the fifth preset liquid level value 100 mm is an analog value.

[0159] The thirteenth result and the liquid level value which is less than the fifth preset liquid level value are subjected to the "OR" logic to obtain the fourteenth result.

[0160] Among them, the fifth preset liquid level value 100mm here is the switch value.

[0161] When the oil purification device is in the activated state and the fourteenth result is satisfied, the oil discharge pump is stopped in an interlocked manner.

[0162] When the oil purification device is in the operating state, the interlocking start and stop of the oil inlet solenoid valve is controlled according to the liquid level monitoring fault signal value, the liquid level value and the fourth preset liquid level value.

[0163] Specifically, Fig.14 The control logic diagram of the interlocked start-stop oil inlet solenoid valve provided by the embodiment of the present invention is shown in FIG. Fig.14 , when the liquid level monitoring fault signal value is 0, and after the "not" logic, the fifteenth result is obtained.

[0164] The fifteenth result, the oil purification device being in operation and the liquid level value being greater than the fourth preset liquid level value are subjected to an "AND" logic to obtain the sixteenth result.

[0165] When the oil purification device is in the engaged state and the sixteenth result is not satisfied, the oil inlet solenoid valve is controlled to open.

[0166] When the oil purification device is in the exit state and the sixteenth result is met, the oil inlet solenoid valve is controlled to be closed.

[0167] It should be noted that the control logic of the oil inlet solenoid valve is controlled by the RS trigger. It is a single-control solenoid valve, that is, when the RS trigger output is 1, the solenoid valve is powered on and opened, and when the RS trigger output is 0, the solenoid valve is de-energized and closed. In other words, S = 1, R = 0, the RS trigger output is 1, and the oil inlet solenoid valve is controlled to open; S = 0, R = 1, the RS trigger output is 0, and the oil inlet solenoid valve is controlled to close.

[0168] The technical solution provided by the embodiment of the present invention effectively avoids turbine tripping and fire accidents caused by low turbine lubricating oil level through real-time monitoring and prejudgment of the oil purification device liquid level. In addition, the oil purification device is included in the DCS control, which solves the problems existing in the original local PLC control and reduces the accident rate. Since the PLC control card and other equipment with high environmental requirements are cancelled on site, and each thermal signal directly enters the signal channel of the DCS separately, the influence of the environment on the thermal control card in the past is eliminated, and the mutual influence between the various signals is also eliminated, which greatly reduces the accident rate. Since each thermal signal directly enters the DCS separately, the DCS system can record the changes of the thermal signal in real time. When an accident occurs, the relevant technicians can easily read the relevant data from the DCS system. The human-machine interface is friendly and intuitive, and the operating personnel can directly operate in the DCS system and can view the equipment operation status in real time at the operator station. The thermal logic configuration is convenient. Since the current logic is implemented in the DCS, the thermal personnel can directly view the relevant logic configuration and forced signals.

[0169] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0170] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A control method for an oil purification device, characterized in that: include: When the oil purification device is in operation, obtain the liquid level value and vacuum value of the oil purification device; determining a liquid level fault type of the oil purification device according to the liquid level value and a first preset control logic; Determining a liquid level monitoring fault signal value according to the liquid level fault type; According to the liquid level monitoring fault signal value, the vacuum value, the liquid level value, the preset liquid level value and the preset vacuum value, the interlocking start and stop of the vacuum pump, the oil inlet pump, the oil discharge pump and the oil inlet solenoid valve are controlled respectively.

2. The control method according to claim 1, characterized in that: Determining the type of liquid level fault of the oil purification device according to the liquid level value and the first preset control logic includes: determining a liquid level signal of the oil purification device according to the liquid level value and a first preset control logic; The liquid level fault type of the oil purification device is determined according to the liquid level signal and the second preset control logic.

3. The control method according to claim 2, characterized in that: Determining the liquid level signal of the oil purification device according to the liquid level value and the first preset control logic includes: If the liquid level value is greater than the preset upper limit of the range after the first preset delay time, or if the liquid level value is less than the preset lower limit of the range after the first preset delay time, a first liquid level signal is output; If the liquid level value is greater than the preset alarm upper limit after the first preset delay time, or if the liquid level value is less than the preset alarm lower limit after the first preset delay time, a second liquid level signal is output; If the rising rate calculated according to the liquid level value is greater than the first preset range percentage after the first preset delay time, or if the falling rate calculated according to the liquid level value is greater than the first preset range percentage after the first preset delay time, then a third liquid level signal is output; If the change rate calculated according to the liquid level value is less than the second preset range percentage after the second preset delay time, a fourth liquid level signal is output.

4. The control method according to claim 3, characterized in that: Determining the type of liquid level fault of the oil purification device according to the liquid level signal and the second preset control logic includes: If the first liquid level signal is output and the liquid level value does not satisfy the condition of being less than the preset upper limit of the measuring range and greater than the preset lower limit of the measuring range after the third preset delay time, it is determined that the liquid level fault type of the oil purification device is a liquid level measurement error; If the second liquid level signal is output and the liquid level value does not satisfy the condition that it is less than the preset alarm upper limit and greater than the preset alarm lower limit after the third preset delay time, it is determined that the liquid level fault type of the oil purification device is liquid level overlimit; If the third liquid level signal is output and the rising rate / falling rate calculated according to the liquid level value does not satisfy the first preset range percentage after the third preset delay time, it is determined that the liquid level fault type of the oil purification device is a large liquid level change rate; If the fourth liquid level signal is output and the change rate calculated according to the liquid level value does not satisfy the second preset range percentage after the fourth preset delay time, the liquid level fault type of the oil purification device is determined to be no change in liquid level.

5. The control method according to claim 4, characterized in that: Determining the liquid level monitoring fault signal value according to the liquid level fault type includes: If the liquid level fault type is one of the liquid level measurement error, the liquid level exceeding the limit, the liquid level changing rate being large, and the liquid level not changing, and the oil purification device is in the operation state, then the liquid level monitoring fault signal value is determined to be 1.

6. The control method according to claim 1, characterized in that: The preset liquid level values ​​include a first preset liquid level value, a second preset liquid level value, a third preset liquid level value, a fourth preset liquid level value and a fifth preset liquid level value, and the preset vacuum value includes a first preset vacuum value and a second preset vacuum value; The interlocking start and stop of the vacuum pump, the oil inlet pump, the oil discharge pump and the oil inlet solenoid valve are controlled respectively according to the liquid level monitoring fault signal value, the vacuum value, the liquid level value, the preset liquid level value and the preset vacuum value, including: When the oil purification device is in operation, the interlocking start and stop of the vacuum pump is controlled according to the liquid level monitoring fault signal value, the vacuum value, the liquid level value, the first preset vacuum value, the second preset vacuum value and the first preset liquid level value; When the oil purification device is in the operation state, the interlocking start and stop of the oil feed pump is controlled according to the liquid level monitoring fault signal value, the liquid level value, the second preset liquid level value and the third preset liquid level value; When the oil purification device is in the operation state, the interlocking start and stop of the oil discharge pump is controlled according to the liquid level monitoring fault signal value, the liquid level value, the fourth preset liquid level value and the fifth preset liquid level value; When the oil purification device is in the operating state, the interlocking start and stop of the oil inlet solenoid valve is controlled according to the liquid level monitoring fault signal value, the liquid level value and the fourth preset liquid level value.

7. The control method according to claim 6, characterized in that: When the oil purification device is in the operation state, controlling the interlocking start and stop of the vacuum pump according to the liquid level monitoring fault signal value, the vacuum value, the liquid level value, the first preset vacuum value, the second preset vacuum value and the first preset liquid level value comprises: When the liquid level monitoring fault signal value is 0 and the liquid level value is less than the first preset liquid level value, a first result is obtained through a "not" logic; When the liquid level monitoring fault signal value is 0, a second result is obtained through the "not" logic; The second result and the liquid level value greater than the first preset liquid level value are subjected to "AND" logic to obtain a third result; When the oil purification device is in the operation state, the vacuum value is greater than the first preset vacuum value, and the first result and the third result are met, the vacuum pump is started in a chain manner; When the oil purification device is in the operation state and the vacuum value is less than the second preset vacuum value, the fourth result is obtained; When the liquid level monitoring fault signal value is 1, or the liquid level value is greater than the first preset liquid level value, it is the fifth result; When the liquid level monitoring fault signal value is 0 and after the "not" logic, and the liquid level value is greater than the first preset liquid level value, after the "and" logic, a sixth result is obtained; If any one of the fourth result, the fifth result and the sixth result occurs, the vacuum pump is stopped in a chain reaction.

8. The control method according to claim 6, characterized in that: When the oil purification device is in the operation state, controlling the interlocking start and stop of the oil feed pump according to the liquid level monitoring fault signal value, the liquid level value, the second preset liquid level value and the third preset liquid level value comprises: When the liquid level monitoring fault signal value is 0 and after the "not" logic, and the liquid level value is less than the second preset liquid level value, after the "and" logic, a seventh result is obtained; The seventh result and the liquid level value being less than the second preset liquid level value are subjected to an "OR" logic to obtain an eighth result; When the oil purification device is in operation and the eighth result is satisfied, the oil inlet pump is started in a chain manner; When the liquid level monitoring fault signal value is 0 and after the "not" logic, and the liquid level value is greater than the third preset liquid level value, after the "and" logic, a ninth result is obtained; The ninth result and the liquid level value greater than the third preset liquid level value are subjected to an "OR" logic to obtain a tenth result; When the oil purification device is in the operation state and the tenth result is satisfied, the oil inlet pump is stopped interlockedly.

9. The control method according to claim 6, characterized in that: When the oil purification device is in the operation state, controlling the interlocking start and stop of the oil discharge pump according to the liquid level monitoring fault signal value, the liquid level value, the fourth preset liquid level value and the fifth preset liquid level value comprises: When the liquid level monitoring fault signal value is 0 and after the "not" logic, and the liquid level value is greater than the fourth preset liquid level value, after the "and" logic, an eleventh result is obtained; The eleventh result and the liquid level value being greater than the fourth preset liquid level value are subjected to an "OR" logic to obtain a twelfth result; When the oil purification device is in operation and the twelfth result is satisfied, the oil discharge pump is started in a chain manner; When the liquid level monitoring fault signal value is 0 and after the "not" logic, and the liquid level value is less than the fifth preset liquid level value, after the "and" logic, a thirteenth result is obtained; The thirteenth result and the liquid level value being less than the fifth preset liquid level value are subjected to an "OR" logic to obtain a fourteenth result; When the oil purification device is in the activated state and the fourteenth result is satisfied, the oil discharge pump is stopped interlocked.

10. The control method according to claim 6, characterized in that: When the oil purification device is in the operation state, controlling the interlocking start and stop of the oil inlet solenoid valve according to the liquid level monitoring fault signal value, the liquid level value and the fourth preset liquid level value comprises: When the liquid level monitoring fault signal value is 0 and after the "not" logic, the fifteenth result is obtained; The fifteenth result, the oil purification device being in the operating state, and the liquid level value being greater than the fourth preset liquid level value are subjected to an "AND" logic to obtain a sixteenth result; When the oil purification device is in the operation state and the sixteenth result is not satisfied, the oil inlet solenoid valve is controlled to be opened; When the oil purification device is in the exit state and the sixteenth result is satisfied, the oil inlet solenoid valve is controlled to be closed.

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