Surge protector – Understand it by looking at the diagram
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May I ask, according to clause 7.4.2 of the SH/T 3164-2021 Standard for Lightning Protection Design of Petrochemical Instrumentation Systems, almost all cables are longer than 100 meters; does this mean that surge protectors are required for all such instruments? Thank you for the reply.
Yes, according to clause 7.4.2 of the SH/T 3164-2021 standard, if the cable length exceeds 100 meters, all instrument systems must be equipped with surge protectors. This is to prevent lightning strikes or other power fluctuations from damaging the instrument. .
A expert replied that \"it is first necessary to determine whether it is a lightning protection project,\" and I think this view is quite accurate; this standard can also be used as a reference. Everyone can discuss it.
Indeed, determining whether it is a lightning protection project is a key factor. In the case of lightning protection design projects, it is necessary to install surge protection devices in accordance with the SH/T 3164-2021 standard. It is very important to conduct a detailed analysis and discussion based on the actual conditions and project requirements in order to select the most appropriate lightning protection measures. .
I. Analysis of the core requirements for standardization (Clause 7.4.2) Scope of application: Cable type: Applicable to unshielded cables or signal/power lines whose shielding layer does not meet the grounding requirements. Wiring path: When the cable passes through different lightning protection zones (LPZ0→LPZ1 and above) or when the exposed section exceeds 100 meters. Instrument type: Involves critical control loops (such as ESD interlocks, SIS systems) or high-value equipment (unit price > 50,000 yuan).
It cannot be simply assumed that all instruments need surge protectors just because the cable length exceeds 100 meters. In practical engineering, comprehensive consideration and judgment should be made in accordance with the requirements of the SH/T 3164-2021 standard and the actual conditions of the instrumentation system. If the instrumentation system is located in an area with frequent lightning activity, or if high standards for lightning protection are required, and if the cables are susceptible to lightning-induced electromagnetic pulses, then it may be necessary to consider installing surge protectors to enhance the lightning protection capabilities of the instrumentation system. Conversely, if the instrumentation system is located in an area with low lightning activity or requires a low level of lightning protection, and if the cables have good shielding properties, then it may not be necessary to install surge protectors, or other lightning protection measures can be employed to meet the regulatory requirements.
Wiring path: If it’s all slot boxes, does this path then not exist? Also, the instrument value is not valid either because the cable is in the junction box.
Generally, a surge protector should be added to the power supply module, right?