Application of DC Signal Surge Protectors in Classified Gas Distribution Stations
发布时间：
2022-03-16
When DC signal surge protectors are used for signal protection, there are many different types. When selecting the appropriate type of surge arrester, users must consider the specific application environment and determine which DC surge protector is most suitable; an improper choice can result in inadequate lightning protection. So, what types of DC signal surge protectors are available?
Application of DC Signal Surge Protectors in Classified Gas Distribution Stations
When DC signal surge protectors are used for signal protection, there are many different types. When selecting the appropriate type of surge arrester, users must consider the specific application environment and determine which DC surge protector is most suitable; an improper choice can result in inadequate lightning protection. So, what types of DC signal surge protectors are available?
In general, DC signal surge protectors can be broadly classified into four categories: network DC signal surge protectors, control DC signal surge protectors, antenna feed DC surge protectors, and rail-mounted DC signal surge protectors. Let’s examine the characteristics of each type.
Network surge protectors are widely used in telecommunications equipment rooms, network interfaces, broadcast control rooms, audio interfaces, and other applications, where they effectively safeguard against lightning-induced surges. Depending on their specific application, they can be categorized for use with routers, program-controlled PBXs, video surveillance systems, switches, and more.
Surge protective devices for control signals are primarily used to provide lightning protection for signal equipment in control circuits, data transmission circuits, industrial control circuits, fire-fighting and alarm circuits, dedicated communication lines, and telemetry signals. In addition, external surge protective devices for DC surges in control signals come in two types: resistive and inductive. Inductive devices are particularly suitable for protecting high-precision sensor circuits.
The DC surge protector for signal rails is designed to safeguard protected equipment from various hazards caused by induced lightning surges and surges on signal transmission lines. Such surge arresters are typically mounted on standard 35 mm DIN rails. Different signal protection lines vary in operating frequency, transmission bandwidth, interface type, and transmission rate.
In China’s gas stations, medium- and low-voltage distribution systems typically supply 220/380 V power, with TN-S and TN-C-S being the predominant earthing configurations. In accordance with the relevant requirements of China’s lightning protection technical codes, in order to prevent lightning current from entering the system and to minimize unnecessary electromagnetic pulse interference, in addition to electromagnetic shielding for overhead power lines, DC surge protective devices are also required. The specific implementation is as follows:
1. Install the DC surge protective device on the incoming external power lines at the boundary between the LPZOA or LPZOB zone and the LPZO1 zone, ensuring that the lightning current waveform passing through the surge protector is 10/350 µs. When the protected circuit is shielded, the lightning current rating for each SPD shall be determined as 30% of the specified current magnitude. Specifically, in the distribution panel, select a switch-type primary-side power surge protective device with a current rating of 100 kA (KSP-1).
2. According to the lightning current diversion theory, each tiered distribution cabinet shall be equipped with a secondary power surge protective device (KSP-80KA/4P/m) featuring an 8/20 µs waveform and a rated discharge current of 80 kA, which can limit the residual induced lightning overvoltage on the 4 kV line to below 2.5 kV.
3. Enhance lightning protection by installing, at the front end of each critical piece of equipment, an 8/20 µs waveform three-stage power surge protector with a discharge current rating of 40 kA (KSP-40KA/4P/m). In addition, to ensure that overvoltage or overcurrent does not damage terminal equipment, fine-tuned power surge protection should be installed at the front end of electrical loads, and a lightning protection strip should be installed at the front end of computer equipment (KS-CP-42N/M).
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