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CN-121984203-A - Method and system for guaranteeing power supply through multiple loops for chemical industry

CN121984203ACN 121984203 ACN121984203 ACN 121984203ACN-121984203-A

Abstract

The invention relates to the technical field of power supply safety in chemical production, in particular to a multi-loop guarantee power supply method and system for chemical industry. The method comprises the steps of configuring a three-stage power supply framework with a main power supply being two-way commercial power, a primary standby power supply being a UPS power supply and a secondary standby power supply being a diesel generator, monitoring the voltage, frequency and harmonic distortion rate of the main power supply in real time by using a PLC, switching to UPS power supply within 10-30ms when the main power supply fails, starting the diesel generator in advance and completing load transfer within 30-60ms when the UPS has insufficient energy storage, and switching back to load according to a principle of first-on-last-off after the main power supply is recovered. The invention realizes millisecond seamless power supply switching, remarkably improves the continuity and reliability of power supply of chemical key equipment, effectively reduces the risk of unplanned shutdown and the probability of safety accidents, and optimizes the operation economy through intelligent management.

Inventors

  • LI YAWEN
  • JIA XIAOJUN
  • SU FENG
  • ZHANG HONGCHANG
  • ZHANG XUEWEN
  • LI QIANG

Assignees

  • 金川集团股份有限公司
  • 金川集团化工新材料有限责任公司

Dates

Publication Date
20260505
Application Date
20251228

Claims (9)

  1. 1. The multi-loop guarantee power supply method for the chemical industry is characterized by comprising the following steps of: Step 1, configuring a multi-loop power supply system, wherein the multi-loop power supply system comprises a main power supply, a primary standby power supply and a secondary standby power supply, the main power supply is a double-path commercial power supply, the primary standby power supply is a UPS (uninterrupted power supply), and the secondary standby power supply is a diesel generator; Step 2, monitoring the voltage, frequency and harmonic distortion rate of a main power supply in real time through a PLC (programmable logic controller) based on a microprocessor, wherein the voltage threshold is AC380V +/-10%, the frequency threshold is 50Hz +/-0.5 Hz, and the harmonic distortion rate threshold is less than 5%; step 3, when the two-way mains supply of the main power supply is simultaneously powered off or the parameter exceeds the threshold value for 50-100 ms, the PLC controller sends a switching-off instruction to the main power supply circuit breaker, and simultaneously sends a switching-on instruction to the UPS power supply output end circuit breaker, and the switching-on instruction is switched to the primary standby power supply for power supply, wherein the switching time is 10-30 ms; Step 4, when the energy storage residual capacity of the UPS is less than 15% -25%, the PLC starts the diesel generator 3-8 minutes in advance, and after the output voltage of the diesel generator is stabilized to AC400V plus or minus 5% and the frequency is stabilized to 50Hz plus or minus 0.2Hz, load transfer from the UPS to the diesel generator is executed, and the switching interruption time is 30-60 ms; and 5, after the main power supply is recovered to be normal and the parameters are monitored stably for 8-15 minutes, the PLC switches the load back to the main power supply from the standby power supply according to the principle of connection before disconnection.
  2. 2. The multi-loop power supply method for chemical industry according to claim 1, wherein the two-way mains supply of the main power supply is from different substations, and the capacities of the two-way mains supply are 150-250 kVA.
  3. 3. The multi-loop power supply method for chemical industry according to claim 1, wherein the capacity of the UPS is 100-200 kVA, and the energy storage time is 20-40 minutes.
  4. 4. The multi-loop power supply method for chemical industry according to claim 1, wherein the capacity of the diesel generator is 200-300 kVA, and the starting time is less than 20 seconds.
  5. 5. The multi-loop power supply guaranteeing method for chemical industry according to claim 1, wherein the PLC integrates a voltage sensor and a current transformer, the precision of the voltage sensor is +/-0.3% - +/-0.8%, and the transformation ratio of the current transformer is 800/5A-1200/5A.
  6. 6. The multi-loop guarantee power supply method for chemical industry according to claim 1, wherein breaking time of the circuit breaker is 15-25 ms.
  7. 7. The multi-loop power supply guaranteeing method for chemical industry according to claim 1, further comprising the step 6 of sending an audible and visual alarm to a DCS central control room by a system when a power failure event is triggered, wherein the response time is less than 5 seconds, recording the power failure time, the switching time and the power supply parameter data, and the storage period is more than 1 year.
  8. 8. A multi-loop guaranteed power supply system for chemical industry, for implementing the method of any one of claims 1 to 7, comprising: The multi-loop power supply module comprises a main power supply, a primary standby power supply and a secondary standby power supply, wherein the main power supply is a double-path commercial power supply, the primary standby power supply is a UPS (uninterrupted power supply), and the secondary standby power supply is a diesel generator; the switching control module comprises a PLC (programmable logic controller) based on a microprocessor, a voltage sensor, a current transformer and a high-speed circuit breaker, wherein the PLC is used for monitoring the voltage, the frequency and the harmonic distortion rate of a main power supply in real time, and the monitoring threshold value of the harmonic distortion rate is less than 5%; the PLC is configured to control the high-speed circuit breaker to switch to the UPS for power supply when the two-way mains supply of the main power supply is simultaneously powered off or the parameter exceeds a threshold value for 50-100 ms, the switching time is 10-30 ms, and start the diesel generator and execute load transfer 3-8 minutes in advance when the energy storage residual capacity of the UPS is less than 15% -25%.
  9. 9. The multi-circuit, power-guaranteeing system for chemical industry according to claim 8, wherein the system meets SIL2 functional safety class requirements.

Description

Method and system for guaranteeing power supply through multiple loops for chemical industry Technical Field The invention belongs to the technical field of power supply safety in chemical production, and particularly relates to a multi-loop guarantee power supply method and system for chemical industry. Background In the chemical production process, the requirements of key equipment such as a reaction kettle, a rectifying tower, a pump group and the like on power supply continuity are extremely high, and any unplanned outage can cause reaction runaway, material solidification or equipment damage, so that serious safety accidents and huge economic losses are caused. According to statistics, the unplanned shutdown rate of the chemical industry caused by the main power failure is up to 37%, wherein about 22% of the unplanned shutdown rate can cause process parameter fluctuation and even safety accidents, and serious defects of the traditional single-loop power supply system in the aspects of reliability and safety are highlighted. There are a number of uninterruptible power supply switching schemes in the prior art, but all have certain limitations. For example, in the electronic factory building power supply guarantee system disclosed in CN114221328a, although equipment is classified and a UPS and a diesel generator are configured, switching logic is relatively simple, specific power quality parameters (such as harmonic distortion) of a chemical environment are not considered, and a multistage cooperative guarantee mechanism for long-time power outage is not formed. Patent CN203278382U provides a continuous switching power supply, which realizes millisecond-level fast switching, but the design of the patent CN203278382U is aimed at a general PLC system, only relates to two-way power supply switching, and lacks a full-link multistage standby architecture aimed at chemical critical equipment and an intelligent pre-judging mechanism based on the state of the standby power supply. The switching control logic of the existing scheme is relatively simple, is mostly judged based on a single voltage or frequency threshold value, and in chemical production, various parameters such as voltage, frequency, harmonic distortion rate and the like need to be comprehensively monitored, and priority dynamic adjustment is realized according to the state of a standby power supply (such as the residual capacity of a UPS), in addition, the existing scheme generally lacks consideration of special requirements on a chemical explosion-proof environment, a functional safety level (such as SIL 2) and the like, and is difficult to meet the severe standard of modern chemical production on power supply safety. Therefore, a multi-loop guarantee power supply method aiming at a chemical production environment is needed to realize a multi-stage standby architecture of a main power supply, a UPS and a diesel generator, and the undisturbed power supply switching is completed within millisecond time through chemical special parameter monitoring and priority switching logic, so that the dual requirements of chemical critical equipment on power supply continuity and safety are met. Disclosure of Invention Aiming at the problems existing in the prior art, the invention provides a multi-loop guarantee power supply method for chemical industry, which comprises the following steps: Step 1, configuring a multi-loop power supply system, wherein the multi-loop power supply system comprises a main power supply, a primary standby power supply and a secondary standby power supply, the main power supply is a double-path commercial power supply, the primary standby power supply is a UPS (uninterrupted power supply), and the secondary standby power supply is a diesel generator; Step 2, monitoring the voltage, frequency and harmonic distortion rate of a main power supply in real time through a PLC (programmable logic controller) based on a microprocessor, wherein the voltage threshold is AC380V +/-10%, the frequency threshold is 50Hz +/-0.5 Hz, and the harmonic distortion rate threshold is less than 5%; step 3, when the two-way mains supply of the main power supply is simultaneously powered off or the parameter exceeds the threshold value for 50-100 ms, the PLC controller sends a switching-off instruction to the main power supply circuit breaker, and simultaneously sends a switching-on instruction to the UPS power supply output end circuit breaker, and the switching-on instruction is switched to the primary standby power supply for power supply, wherein the switching time is 10-30 ms; Step 4, when the energy storage residual capacity of the UPS is less than 15% -25%, the PLC starts the diesel generator 3-8 minutes in advance, and after the output voltage of the diesel generator is stabilized to AC400V plus or minus 5% and the frequency is stabilized to 50Hz plus or minus 0.2Hz, load transfer from the UPS to the diesel generator is executed, and the switching in