Accurate protection system for valve control box

Abstract

The invention discloses a precise protection system for a valve control box, and relates to the technical field of valves. The system comprises a power supply module, a detection module, a control module and an execution module, power is supplied through a circuit breaker and a switching power supply, current / voltage parameters are monitored in real time through the detection module, and a relay is driven to control valve action and state indication after being processed by the control module. The protection logic meets a specific mathematical expression, over-current, over-voltage and under-voltage protection can be accurately realized, and the response time is short. The system has the advantages of high protection precision, strong real-time monitoring capability, high reliability, clear state indication, low energy consumption and the like, can effectively solve the problems of single protection function, insufficient precision and the like of a traditional control box, is suitable for various industrial scenes, and can reduce the maintenance cost and the energy consumption.

Description

Technical Field

[0001] This invention relates to the field of valve technology, specifically a precision protection system for valve control boxes. Background Technology

[0002] In the field of industrial valve control, traditional valve control boxes are mainly used to realize the opening / closing operation of valves, and their core structure typically includes:

[0003] 1. Switch control module: Directly controls the valve motor to open or close via relay or contactor, realizing the "OPEN" and "SHUT" actions;

[0004] 2. Protection module: Thermal relays are often used as overload protection components. Some control boxes only have basic short-circuit protection (such as circuit breakers) and lack real-time monitoring of electrical parameters such as overvoltage and undervoltage.

[0005] 3. Power supply module: It adopts a simple transformer or resistor-capacitor step-down method to convert AC power into low-voltage DC power, which has poor stability;

[0006] 4. Status indicator module: Only a simple on / off status indicator light is configured, without fault alarm function.

[0007] Its working principle is as follows: a relay is triggered by a manual button or an external signal to control the power supply circuit of the valve motor. The thermal relay is connected in series in the motor circuit. When the current exceeds the rated value, the thermal element heats up and the contacts open, thus achieving overload protection. However, this protection method relies on the heat conduction of the mechanical structure, has a long response time (usually several seconds to tens of seconds), and the protection threshold cannot be precisely adjusted.

[0008] Problems with existing technology:

[0009] 1. Traditional control boxes can only provide overload protection and cannot monitor abnormal conditions such as overvoltage and undervoltage. Furthermore, the protection accuracy error of thermal relays exceeds 10% (e.g., when the rated current is 2A, the actual protection threshold may be above 2.2A), which cannot meet the needs of high-precision industrial scenarios.

[0010] 2. The existing control box lacks a real-time sampling module for current and voltage, and cannot provide timely warnings in the early stages of abnormal parameters (such as the current slowly rising to 110% of the rated value). It is often only discovered after the valve is overloaded and damaged, which leads to prolonged equipment downtime and increased maintenance costs.

[0011] 3. The power supply module of traditional control boxes has poor stability (such as using RC step-down), and voltage fluctuations can easily cause relays to malfunction; moreover, there is no heat dissipation design, and components (such as relay contacts and capacitors) are prone to aging after long-term operation, resulting in a high failure rate.

[0012] 4. The existing control box can only display the valve open / close status and cannot indicate fault information such as power abnormality or protection action. Maintenance personnel need to use tools such as multimeters to check segment by segment, which takes a long time to troubleshoot.

[0013] 5. Traditional control boxes have a power conversion efficiency of less than 60% (such as transformer step-down method), resulting in serious energy waste; and the wiring method is complicated (such as valve body wiring terminals without clear function markings), which can easily lead to short circuit faults due to wiring errors during installation.

[0014] Therefore, based on this, we have studied and improved the existing technology and proposed a precision protection system for valve control boxes. Summary of the Invention

[0015] The technical problem this invention aims to solve is to overcome the problems of traditional valve control boxes, such as limited protection functions (relying solely on thermal relays for overload protection, lacking overvoltage and undervoltage protection), insufficient protection accuracy (error exceeding 10%), lack of real-time monitoring capabilities (unable to collect current and voltage parameters in real time and issue early warnings), low system reliability (poor stability of power supply modules and easy aging of components), insufficient status visualization (no fault alarm function), and high energy consumption. The invention provides a valve control box precision protection system with accurate overcurrent, overvoltage, and undervoltage protection functions, capable of real-time monitoring of electrical parameters and rapid response, high reliability, and clear status indication.

[0016] The technical solution adopted in this invention is: a valve control box precision protection system, comprising:

[0017] The power supply module is used to provide working power and includes a circuit breaker QF and a switching power supply SMPS. The input terminal of the circuit breaker QF is connected to the phase line L, the neutral line N and the ground line PE, and the output terminal is electrically connected to the input terminal of the switching power supply SMPS.

[0018] The detection module is used to monitor current / voltage parameters in real time. Its input terminal is connected to the output terminal of the power supply module, and its output terminal is electrically connected to the control module.

[0019] The control module includes a commutation module and relays KA1 and KA2. The power supply terminal of the commutation module is connected to the +24V output of the switching power supply SMPS, the signal input terminal is electrically connected to the output terminal of the detection module, and the signal output terminal is electrically connected to the coils of relays KA1 and KA2.

[0020] The execution module includes a valve body and status indicator lights HD1, HD2, and HD3. The contacts of relays KA1 and KA2 respectively control the opening and closing circuit of the valve body and the on / off state of the indicator lights.

[0021] The protection logic of the detection module satisfies the following mathematical expression:

[0022]

[0023] Among them, I detected To detect the current, U detected To detect voltage, I rated For the rated current, U rated The rated voltage is δ, and the protection accuracy coefficient is 0 < δ ≤ 0.1.

[0024] As a further aspect of the present invention: in the power supply module, the rated current of the circuit breaker QF satisfies:

[0025] I QF ≥k×I rated

[0026] Where k is the safety factor, 1.2≤k≤1.5, and the conductor cross-sectional area is 1 mm². 2 Its current-carrying capacity satisfies:

[0027] I wire ≥I QF .

[0028] As a further aspect of the present invention: the signal processing procedure of the detection module satisfies:

[0029] Otherwise

[0030]

[0031] Among them, S in S is the input current / voltage signal. ref As a reference threshold, S out This is the output switch signal (1 indicates abnormal, 0 indicates normal).

[0032] As a further aspect of the present invention: the control logic of the commutation module satisfies:

[0033] When the detection module outputs an abnormal signal, the commutation module outputs a control signal to activate relays KA1 and KA2, with an activation time t. action satisfy:

[0034] t action =t delay +t response

[0035] Among them, t delay The preset delay time is (0.5s≤t). delay ≤2s), t response This refers to the relay response time.

[0036] As a further aspect of the present invention: the wiring terminals of the valve body include 5 terminals, and the circuit continuity condition satisfies:

[0037] path

[0038] Passage=(KA1 contact ∨KA2 contact )∧(QF closed )

[0039] Among them, KA1 contact KA2 contact These represent the contact states of relays KA1 and KA2 (1 indicates closed, 0 indicates open), QF closed The circuit breaker status is indicated by 1 (1 indicates closed, 0 indicates open).

[0040] As a further aspect of the present invention: the logic control of the status indicator light satisfies:

[0041] When the off status indicator HD1 is on:

[0042] When the status indicator HD2 is lit: HD2 = KA2 contact ∧QF closed

[0043] When fault indicator HD3 is lit: HD3 = S out ∧QF closed

[0044] in, This indicates the NOT logic of the KA2 contact.

[0045] As a further aspect of the present invention: the overcurrent protection threshold of the protection system is set as follows:

[0046] I protect =I rated ×(1+δ)

[0047] When the detection current I detected Satisfy I detected ≥I protect When the protection action is triggered, the action delay is t. delay satisfy:

[0048]

[0049] Among them, T base As a reference delay (1s≤T) base ≤3s).

[0050] As a further aspect of the present invention: the sampling frequency f of the detection module s satisfy:

[0051] f s ≥2×f max

[0052] Among them, f max The highest harmonic frequency of the grid voltage / current is used to ensure that the sampling conforms to the Nyquist sampling theorem.

[0053] As a further aspect of the present invention: the output power P of the switching power supply SMPS out satisfy:

[0054]

[0055] Among them, P i P represents the power consumption of each module (detection module, commutation module, relays, etc.). res To reserve power margin

[0056] As a further aspect of the present invention: the overall malfunction rate R of the protection system error satisfy:

[0057]

[0058] Where, p j Let R be the failure rate of each module, and m be the total number of system modules. Through redundant design and parameter optimization, R can be optimized. error ≤10 -4 Once per year.

[0059] The beneficial effects of this invention are:

[0060] 1. Dual improvement in protection accuracy and response speed

[0061] Mathematical protection logic based on the detection module (threshold formula I) protect =I rated ×(1+δ), δ≤0.1), to achieve current / voltage protection accuracy control within ±0.1A / ±1V, which is more than 10 times better than the 10% error of traditional thermal relays;

[0062] The linkage response time t between the commutation module and the relay action =t delay +t response (t delay With a travel time of ≤2s, it shortens the mechanical action time of traditional thermal relays (5-10s) by at least 60%, enabling rapid disconnection of fault circuits in the early stages of abnormal parameters and preventing overheating damage to valve motors.

[0063] 2. Real-time monitoring and fault early warning capabilities for all parameters

[0064] The detection module adopts the Nyquist sampling theorem (f s ≥2×f maxDesign the sampling frequency to acquire current / voltage signals in real time, and use Boolean logic expressions (S) out =f(S) in Identifying abnormal conditions can help detect latent faults such as slow current increases and voltage fluctuations in advance, thus avoiding unplanned shutdowns.

[0065] Logical relationship between status indicator lights HD1-HD3 and relay contact status (HD3 = S) out ∧QF closed This system provides a visual indication of valve opening and closing status, power supply status, and fault signals. Maintenance personnel can quickly locate anomalies using indicator lights, reducing troubleshooting time by more than 70%.

[0066] 3. System reliability and stability optimization

[0067] The power supply module adopts a switching power supply SMPS(P) out ≥∑P i +P res P res ≥0.2∑P i The conversion efficiency is increased to over 85%, reducing energy consumption by 30% compared to the traditional resistor-capacitor step-down method. At the same time, the power margin design reduces component heat generation and extends service life.

[0068] The contact states of relays KA1 and KA2 and the logic control of the valve circuit (path path = (KA1) contact ∨KA2 contact )∧QF closed To avoid the risk of short circuits due to wiring errors, the overload protection of the circuit breaker QF (I) is combined with the circuit breaker QF. QF ≥k×I rated (k≥1.2), forming a multi-level protection mechanism, the overall system malfunction rate R error ≤10 -4 This reduces the number of times per year by more than 90% compared to traditional methods.

[0069] 4. Improved intelligence and adaptability

[0070] Overcurrent protection delay t delay Linear relationship with current deviation The protection time can be dynamically adjusted according to the degree of abnormality to avoid malfunctions when the motor starts, and adapt to the valve control requirements under different working conditions;

[0071] The standardized interface design of the detection module and the commutation module (such as IN± and MT± terminals) supports seamless integration with industrial control systems such as PLC and DCS, enabling remote monitoring and parameter adjustment, and improving the degree of automation compared with traditional local control methods.

[0072] 5. Overall reduction in maintenance costs and energy consumption

[0073] By precisely protecting the valve motor, the probability of it burning out due to overload can be reduced. According to statistics from industrial sites, the frequency of motor replacement can be reduced from 3-5 times per year to less than 0.5 times, and the annual maintenance cost can be reduced by 60%.

[0074] The application of switching power supplies and high-efficiency relays reduces the standby power consumption of the control box from 15-20W in traditional solutions to below 5W. Based on 24-hour operation, the annual power consumption is reduced by approximately 8760kWh, demonstrating significant energy-saving effects. Attached Figure Description

[0075] Figure 1 This is a schematic diagram of the overall system for a valve control box precision protection system according to the present invention.

[0076] Figure 2 This is an electrical diagram of the valve protection electrical box of a valve control box precision protection system according to the present invention.

[0077] Figure 3 This is a timing diagram of the protection logic for a precision protection system for a valve control box according to the present invention. Detailed Implementation

[0078] The present invention will be further described below.

[0079] See also Figure 1-3

[0080] Example 1: Basic Protection System Based on Hardware Modular Design

[0081] 1. System Composition and Connection

[0082] Power supply module: Uses circuit breaker QF (model: DZ47-63 / C10), rated current 10A, input terminals connected to AC220V phase line L, neutral line N, and ground line PE, output terminals connected to switching power supply SMPS (model: DR-24-24, power 24W, output +24VDC), conductor cross-sectional area 1mm². 2 Copper core wire, meeting I QF =10A≥1.2×I rated (Assuming the valve's rated current I) rated =8A).

[0083] The detection module integrates a Hall current sensor (model: ACS712, range ±30A) and a voltage sampling resistor (accuracy 0.1%). The input is connected in parallel to the valve motor circuit, and the output is connected to an MCU (STM32F103) via an operational amplifier (LM358) to achieve AD conversion of the current / voltage signal. The sampling frequency is f. s =10kHz≥2×f max (the highest harmonic frequency of the power grid f)max =4kHz).

[0084] Control Module: The commutation module uses solid-state relays (SSR-24VDC), with the power supply terminal connected to the +24V of the SMPS and the signal input terminal connected to the I / O port of the MCU. The coils of relays KA1 and KA2 (model: JQC-3FF / 24V) are connected in series with the output terminal of the solid-state relays, and the contacts control the opening / closing circuit of the valve motor and the indicator lights HD1-HD3 (LED lights, 24V) respectively.

[0085] Execution module: The valve body is an electric ball valve (DN50), with 5 terminals corresponding to the three-phase windings of the motor and the common terminal respectively. The status indicator lights HD1 (green), HD2 (red), and HD3 (yellow) are connected in parallel to the relay contact circuit.

[0086] 2. Working principle

[0087] When the valve motor starts, the circuit breaker QF closes, and the SMPS outputs +24V to power the detection module and control module. The detection module samples the current I in real time. detected With voltage U detected , if I detected >8A×(1+0.1)=8.8A (δ=0.1), the MCU outputs a high level to the commutation module, triggering relay KA1 to disconnect, and simultaneously HD3 lights up, realizing overcurrent protection. Protection action time t action =0.5s(t) delay =0.3s,t response =0.2s), which is 80% shorter than traditional thermal relays.

[0088] Example 2: Optimized Implementation of Adaptive Delay Protection

[0089] 1. Core parameter design

[0090] The detection module employs a dual-threshold sampling strategy: during normal operation, the sampling frequency f s =2kHz, when |(I detected -I rated ) / I rated When |≥0.05, the sampling frequency is automatically increased to 10kHz to ensure high-frequency acquisition of abnormal signals.

[0091] Overcurrent protection delay t delay Based on dynamic calculation of current deviation: when I detected =1.2I rated At that time, t delay =(1.2-1) / 1×2s=0.4s; when I detected =1.5I rated At that time, t delay= (1.5-1) / 1×2s = 1s, to avoid malfunctions during motor startup (starting current is usually 3-5 times the rated current).

[0092] 2. Hardware improvements

[0093] An RC filter circuit (100Ω resistor, 0.1μF capacitor) is added between the detection module and the MCU to suppress high-frequency interference and ensure S in The stability of the signal makes S out The false positive rate is ≤0.1%.

[0094] Output power P of the switching power supply SMPS out =24W≥∑P i +0.2∑P i The power consumption includes a 5W detection module, an 8W commutation module, 2×2W relays, and 3×1W indicator lights, with a reserved power margin P. res =6W, satisfying P res ≥0.2×(5+8+4+3)=4W.

[0095] Example 3: Implementation of Industrial-Grade Anti-Interference and Remote Monitoring

[0096] 1. Anti-interference design

[0097] The control box casing is made of 1.5mm thick cold-rolled steel plate, and an independent grounding copper busbar (cross-sectional area ≥4mm²) is installed inside. 2 The PE line is connected in a star configuration to the grounding terminal of each module to reduce grounding loop interference.

[0098] The signal cable of the detection module uses twisted-pair shielded cable (AWG24), with the shielding layer grounded at one end to avoid magnetic field coupling interference and ensure I... detected The sampling error is ≤ ±0.5%.

[0099] 2. Remote monitoring integration

[0100] An RS485 communication interface (chip: MAX485) is added to the ND and COM terminals of the commutation module to transmit the detection data (I) via the Modbus protocol. detected U detected S out The data is uploaded to the PLC (model: S7-200SMART) to enable remote threshold setting (such as dynamically adjusting δ to 0.05) and fault alarm.

[0101] The status indicator HD3 is connected in parallel with the relay contacts and the buzzer (24V, 85dB). When HD3=1, an audible and visual alarm is issued simultaneously, shortening the local maintenance response time to within 10 seconds.

[0102] Example 4: Explosion-proof implementation in high-risk environments

[0103] 1. Explosion-proof structural design

[0104] The control box housing is designed with an ExdIICT6 explosion-proof rating and is made of cast aluminum alloy with an anti-corrosion coating. All wiring ports are equipped with explosion-proof glands (model: PG13.5) to ensure that internal components are isolated from hazardous environments.

[0105] The circuit boards of the detection module and control module are encapsulated using epoxy resin AB glue, achieving an IP65 protection rating. They can operate stably in environments with temperatures ranging from -20℃ to +60℃ and humidity ≤95%RH.

[0106] 2. Intrinsically safe circuit optimization

[0107] The switching power supply SMPS was replaced with an explosion-proof intrinsically safe power supply (model: KDW127 / 12B), with an output voltage of +12VDC and a maximum power of 10W, meeting P requirements. out ≥∑P i +P res (∑P i =8W, P res =2W).

[0108] Relays KA1 and KA2 have been replaced with intrinsically safe relays (coil power ≤ 0.5W) with a contact capacity of 24V / 1A. They are isolated from the valve motor by a safety barrier (model: MTL5041) to prevent the risk of explosion caused by electrical sparks.

[0109] Example 5: Implementation of Multi-Valve Cluster Monitoring

[0110] 1. System Topology

[0111] The system adopts a master-slave distributed control: one master control box (structure of Example 1) is connected to eight sub-control boxes via a CAN bus (baud rate 1Mbps). Each sub-control box corresponds to one valve, realizing clustered protection and monitoring.

[0112] The sampling frequency f of the detection module in the main control box s =5kHz, the I of each sub-control box is processed by a weighted average algorithm. detected Data, when any sub-control box I detected >I rated When ×(1+δ), the main control box synchronously sends out a cluster alarm signal.

[0113] 2. Energy consumption optimization strategy

[0114] When the valve is stationary, the sub-control box enters a low-power mode: the SMPS output voltage drops to +12V, the sampling frequency of the detection module drops to 500Hz, the power consumption drops from 5W to 2W, the overall energy consumption is reduced by 60%, and the annual power consumption is reduced by about 12,000 kWh compared with the traditional solution.

[0115] Example verification and effect comparison

[0116]

[0117]

[0118] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A precision protection system for a valve control box, characterized in that, include: The power supply module is used to provide working power and includes a circuit breaker QF and a switching power supply SMPS. The input terminal of the circuit breaker QF is connected to the phase line L, the neutral line N and the ground line PE, and the output terminal is electrically connected to the input terminal of the switching power supply SMPS. The detection module is used to monitor current / voltage parameters in real time. Its input terminal is connected to the output terminal of the power supply module, and its output terminal is electrically connected to the control module. The control module includes a commutation module and relays KA1 and KA2. The power supply terminal of the commutation module is connected to the +24V output of the switching power supply SMPS, the signal input terminal is electrically connected to the output terminal of the detection module, and the signal output terminal is electrically connected to the coils of relays KA1 and KA2. The execution module includes a valve body and status indicator lights HD1, HD2, and HD3. The contacts of relays KA1 and KA2 respectively control the opening and closing circuit of the valve body and the on / off state of the indicator lights. The protection logic of the detection module satisfies the following mathematical expression: Among them, I detected To detect the current, U detected To detect voltage, I rated For the rated current, U rated The rated voltage is δ, and the protection accuracy coefficient is 0 < δ ≤ 0.

1.

2. The valve control box precision protection system according to claim 1, characterized in that, In the power supply module, the rated current of circuit breaker QF satisfies: I QF ≥k×I rated Where k is the safety factor, 1.2≤k≤1.5, and the conductor cross-sectional area is 1 mm². 2 Its current-carrying capacity satisfies: I wire ≥I QF 。 3. The valve control box precision protection system according to claim 1, characterized in that, The signal processing procedure of the detection module satisfies: Otherwise Among them, S in S is the input current / voltage signal. ref As a reference threshold, S out This is the output switch signal (1 indicates abnormal, 0 indicates normal).

4. The valve control box precision protection system according to claim 1, characterized in that, The control logic of the commutation module satisfies: When the detection module outputs an abnormal signal, the commutation module outputs a control signal to activate relays KA1 and KA2, with an activation time t. action satisfy: t action =t delay +t response Among them, t delay The preset delay time is (0.5s≤t). delay ≤2s), t response This refers to the relay response time.

5. The valve control box precision protection system according to claim 1, characterized in that, The valve body has 5 terminals, and its circuit continuity condition satisfies: path Passage = (KA1 contact ∨KA2 contact )∧(QF closed ) Among them, KA1 contact KA2 contact These represent the contact states of relays KA1 and KA2 (1 indicates closed, 0 indicates open), QF closed The circuit breaker status is indicated by 1 (1 indicates closed, 0 indicates open).

6. The valve control box precision protection system according to claim 1, characterized in that, The logic control of the status indicator light satisfies: When the off status indicator HD1 is on: When the status indicator HD2 is lit: HD2 = KA2 contact ∧QF closed When fault indicator HD3 is on: HD3 = S out ∧QF closed in, This indicates the NOT logic of the KA2 contact.

7. A valve control box precision protection system according to claim 1, characterized in that, The overcurrent protection threshold of the protection system is set as follows: I protect =I rated ×(1+δ) When the detection current I detected Satisfy I detected ≥I protect When the protection action is triggered, the action delay is t. delay satisfy: Among them, T base As a reference delay (1s≤T) base ≤3s).

8. The valve control box precision protection system according to claim 1, characterized in that, The sampling frequency f of the detection module s satisfy: f s ≥2×f max Among them, f max The highest harmonic frequency of the grid voltage / current is used to ensure that the sampling conforms to the Nyquist sampling theorem.

9. A valve control box precision protection system according to claim 1, characterized in that, The output power P of the switching power supply SMPS out satisfy: Among them, P i P represents the power consumption of each module (detection module, commutation module, relays, etc.). res To reserve power margin 10. A valve control box precision protection system according to claim 1, characterized in that, The overall malfunction rate R of the protection system error satisfy: Where, p j Let R be the failure rate of each module, and m be the total number of system modules. Through redundant design and parameter optimization, R can be optimized. error ≤10 -4 Once per year.

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