Discussion on Intelligent Power Distribution Cabinets
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Dear marine friends, everything is being upgraded and evolved these days, and distribution cabinet technology is also advancing. This is an inevitable trend, a necessity of technological progress! In the past, electrical distribution cabinets were used solely to supply power to certain devices or to control them; small devices were installed in some of the circuits within these cabinets to collect signal data, which was then connected via hard wiring to the PLC/DCS modules in the automatic control cabinet, thereby enabling signal collection or command transmission. (Things like small contactors, current transformers, etc.) This is the industrial control mode that is widely used today. There are several disadvantages: 1. Some control rooms are equipped with electrical cabinets, while others have control cabinets. It takes up space, increases construction work, and raises costs. 2 A large number of signal cables need to be laid between the electrical cabinets and the automatic control cabinets, which also increases the workload and the cost of construction. Given that, why not install the signal acquisition modules directly in each cabinet of the distribution panel as needed? These are distributed I/O modules; they’re just more dispersed than traditional distributed systems – in this case, the modules are installed directly inside the electrical cabinets. A large number of hardwired communication cables are also eliminated, as are the module locations within the control cabinets. In this way, signals can be transmitted to the PLC/DCS via module communication; the control room only needs to be equipped with CPU modules, as the acquisition modules are all installed in various electrical cabinets. Electrical cabinets now come with communication functions built-in, but they aren’t yet widely used; I’m not sure why. Are current regulations still preventing such installation? ? Afraid of electromagnetic interference? ? What do you all, sea friends, think? ! !
Electrical systems also have monitoring systems; although such systems are more expensive, they help reduce labor costs, ensure accurate detection, provide timely alerts, and enable precise judgments, thus preventing motor damage, equipment failure, and unplanned downtime. But it is used less now. The main network is ； Install the motor microcomputer main protector or the feeder microcomputer integrated protector (depending on the choice of protection equipment) in the electrical control cabinet. It communicates with the device management computer via 485, and the entire electrical network can be monitored through the configuration interface of the upper-level system. It is also possible to connect a cable (or fiber optic cable) directly from the communication device to the DCS (PLC/FCS); just a few hundred meters of cable are sufficient. There are several issues that need to be addressed in this regard ； 1. Standardization of communication protocols, using the standard Madbus protocol. 2. Communication protocols 3. Approval from corporate leadership and shift in mindset
This technology is already quite mature. In 2003, I worked on a project at an oil field facility where we manufactured power distribution cabinets; we installed centralized communication modules in each MNS power distribution cabinet to monitor the electrical parameters of each circuit. The circuit breakers and fuses were controlled electronically, and remote monitoring was enabled via the 485 communication protocol connected to a computer. We built a set of 7 switchgear cabinets, obtained 3C certification for them, and eventually sold one such system at the Daqing Oil Field – it consisted of around 5 cabinets, with the cost per cabinet being over 10,000 yuan. In the end, the cost remains high, project budgets are limited, and thus widespread adoption is not possible.
Every project designed by our company includes such a reserved network communication interface, RS485, to facilitate future modifications and upgrades; this technology is indeed quite mature. In high-pressure control systems, it is designed this way, and optical fibers are used.