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With the rapid development of production automation, manufacturing enterprises have increasingly stringent requirements regarding electricity supply. In particular, continuous-production enterprises place greater emphasis on the “quality” of electrical power. As reliance on electrical automation grows, it drives continuous innovations in this field, enabling electrical automation to gradually replace traditional manual operations or relay control. The FSC disturbance-free transfer switch cabinet is specifically designed to ensure seamless switching between safe power sources on the incoming side of medium- and low-voltage systems. The FSC medium and low voltage disturbance-free switching cabinet is designed based on the actual power consumption needs of enterprises, taking into account the conditions of the power usage environment on site. It utilizes advanced switching technologies, sophisticated data collection and processing capabilities, as well as innovative operation principles to completely eliminate the problems caused by voltage fluctuations or unplanned power outages. The FSC medium- and low-voltage disturbance-free switching cabinet collects all information to be measured and input signals on both the high- and low-voltage sides, and makes a reasonable allocation of the output signals that need to be controlled. The disturbance-free fast transfer device aggregates various pieces of information from the site, such as bus voltage, incoming line voltage, incoming line current, and switch positions. Based on the system’s operating status, it promptly disconnects the faulty power source. When the voltage levels on both sides of the circuit to be closed meet the required criteria, it connects the backup power source. This prevents any power interruptions or damage to equipment caused by sudden power switching, thereby ensuring uninterrupted and disturbance-free operation of the load. Uninterrupted switching of power supplies is an important measure to ensure power supply reliability. What does power supply reliability mean? The traditional understanding is that it refers to the ability of a load to continue operating after losing one power source and obtaining a new one; this is the definition of reliability. The methods by which this can be achieved include manual switching, relay control, or the automatic transfer switch systems used in microcomputer-based comprehensive protection systems. However, these three methods are relatively simple and can no longer meet the power requirements of modern enterprises that operate on a continuous basis. When there are power fluctuations or unplanned outages, it becomes difficult for such enterprises to continue operating normally to the fullest extent, which leads to a series of \"failures\" or \"accidents.\" For manufacturing enterprises, the biggest challenge is how to maintain normal production to the greatest extent possible during power fluctuations or switching operations. The occurrence of voltage fluctuations is caused by multiple factors. When voltage fluctuations or unplanned power outages happen, traditional methods used in the past include manual switching operations, relay control, or automatic transfer switches within microcomputer-based integrated protection systems. This is achieved through the combination of the above three methods and on-site vacuum circuit breakers. Whichever method is used, it will cause the equipment to shut down, disrupting continuous production and resulting in significant financial losses ； Interruptions at key points in the production process affect product quality and waste raw materials ； For equipment designed to ensure safety, this is even more serious, as it can potentially result in casualties at any time. These are all fatal and irresistible factors for enterprises; thus, it is evident that previous manual switching or automatic control methods can hardly meet the current requirements of manufacturing enterprises regarding electricity usage. Among the aforementioned methods: operations such as manual switching, voltage fluctuations in the system, or unplanned power outages are, in most cases, impossible to predict in advance; by the time an accident occurs, it is already too late to take manual corrective actions ； For example, in relay control systems, there are numerous components, making the system complex. These systems have poor anti-interference capabilities and many potential failure points, which directly results in low reliability, poor sensitivity, inadequate selectivity, and excessively long operating times ； Take the automatic transfer switch system in microcomputer-based integrated protection as an example. Although it represents intelligent control, it operates by detecting the residual voltage on the busbar; closing occurs when there is no voltage or current. At this point, the busbar is already voltage-free, and all equipment has completely ceased operating. Meanwhile, since the operating mechanisms on-site are mostly composed of vacuum circuit breakers, their internal operation relies largely on springs. The force exerted by these springs is non-linear, and the operating time is excessively long; furthermore, arcing occurs at the contacts during the closing process. Therefore, the several traditional methods mentioned earlier can no longer meet the current electricity demands of enterprises. Furthermore, the actuators available on the market are mostly vacuum circuit breakers. Their advantages include low cost and mature technology, while their disadvantages are that they rely on springs for operation, and the force generated by these springs is nonlinear. The age of the equipment directly affects its operating time – the older the equipment, the longer it takes to operate – and arcing occurs during the closing of the contacts. The FSC medium and low voltage disturbance-free switching cabinet primarily addresses the following issues: 1) It enables disturbance-free switching in the event of voltage fluctuations or unplanned power outages, ensuring that the loads do not stop operating. 2) Multiple starting modes for rapid identification, with the ability to monitor information such as voltage amplitude, frequency, and phase in real time. 3) Intelligent identification of faults inside and outside the zone to prevent false trips, with automatic holographic waveform recording in case of voltage disturbances. 4) The operating part uses a high-speed vacuum circuit breaker, with a permanent magnet operating mechanism inside. 5) It features short operating time, high consistency, fast arc extinction, and long service life. The FSC medium and low voltage disturbance-free switching cabinet is equipped with an independent microcomputer-based integrated protection device; the disturbance-free switching control system and the relay protection system are completely separate from each other, **which enhances the reliability of the cabinet and enables rapid identification of faults, whether they occur within or outside the circuit area. Automatic recording is initiated in response to bus voltage disturbances, as well as during switching operations; this facilitates the monitoring of grid disturbances, the inversion of switching processes, and the analysis of switching-induced disturbances. During switchgear operations, seamless one-click switching ； When a voltage dip occurs in the power grid, it switches quickly and seamlessly to a backup feed to ensure continuous operation of the load without any interruption. It comes standard with dual RS485 communication interfaces and dual 100M Ethernet communication interfaces, supporting common communication protocols. A 4G communication module can be installed according to user requirements, enabling remote maintenance via a mobile phone as well as waveform viewing through an encrypted gateway. As shown in the figure, this is the structural diagram of the low- and medium-voltage disturbance-free switching cabinet in the FSC. The primary circuit wiring of this disturbance-free switching cabinet features connections that enter from below and exit from above. The cable room area is primarily used for hanging incoming cables, as well as installing voltage transformers, grounding switches, arresters, and other devices ； The circuit breaker room area is composed of high-speed vacuum circuit breakers, trays, temperature probes, partitions, and other accessories ； The secondary instrument room area is equipped with accessories such as microcomputer-based circuit protection, disturbance-free quick switching, power distribution analysis instruments, intelligent operation displays/live display devices, and secondary wiring terminals. Voltage disturbances in the power grid are primarily caused by external power grids and faults within the grid itself. Voltage dips that result from such disturbances can, if they persist for a certain period of time, trigger alarms and cause the frequency converters to shut down. This, in turn, leads to loss of control over the secondary control circuits, resulting in the shutdown of the production system. In severe cases, this can lead to production accidents and casualties. To address the issue that has been plaguing everyone, the solution proposed by the FSC medium and low voltage disturbance-free switching cabinet is rapid switching. Fast switching requires a power supply with sufficient capacity, as well as a fast switching process to ensure that the device is not aware of the switch. It also requires high reliability, accurate detection of faults both within and outside the area, composite criteria for detecting PT wire breaks, and recording of various measurement data during system voltage dips. With disturbance-free rapid switching, system sampling and analysis are utilized; when there is a voltage dip in the system’s power supply, it is possible to quickly detect this situation and issue commands to operate the vacuum circuit breaker in order to cut off the faulty power source. The vacuum circuit breaker on the side of the safe power supply is then closed swiftly and intelligently, ensuring that the equipment remains powered without any interruptions or shocks during the rapid power switching process, thus allowing the system to continue operating continuously over the long term ； High-speed vacuum circuit breakers, permanent-magnet high-speed vacuum circuit breakers with unique technology, featuring short operating time, high consistency, fast arc extinction, and long service life ； The microcomputer-based line protection device enables rapid detection of faults within its coverage area, and works in conjunction with disturbance-free quick switching to achieve fast isolation of such faults. It features functions such as three-stage overcurrent protection, charging protection, and overload protection. The FSC medium-low voltage disturbance-free quick switching cabinet is an integrated solution designed to ensure a disturbance-free switchover of the safe power supply on the incoming line side; it improves compatibility among the control unit, actuation unit, and protection unit, offering fast switching speeds and higher reliability.