1 Introduction
In recent years, Yanzhou Mining (Group) Co., Ltd. has conducted research on the problems existing in the operation of various types of uninterruptible power systems (UPS) and emergency power systems (EPS) in coal mines, and on this basis, the existing operation and maintenance facilities Improvements have been made to improve the useful life of various types of UPS and EPS systems used in mines and effectively ensure the safety of mine production.
2 Correct selection and reasonable configuration of network UPS
The form of power supply and distribution of LAN systems - Uninterruptible Power System (UPS), is a high-tech power system that integrates power technology, control technology, and signal detection and communication technology. It is widely used in local area networks for data processing and data. Transmission and other occasions with high reliability requirements. The calculation center of Luzhou Mining (Group) Co., Ltd. conducts research on the correct selection and rational configuration of the UPS for the LAN system to ensure the normal operation of the LAN.
In the LAN system, the purpose of selecting a UPS is mainly to provide equipment backup power to prevent sudden power failure, resulting in data loss, network interruption and other failures; elimination of excessive voltage or low voltage caused by the utility grid, power surge and other phenomena Improving the power supply quality; suppressing electromagnetic interference, high-frequency signals, and other noise interference generated by other high-power electrical equipment in the power grid.
(1) Characteristics of UPS
1 The high reliability of the UPS ensures the normal operation of the LAN throughout the day
Responsibility requirements of UPS power supply system: Do not allow any momentary abnormal power supply accident; It does not allow the power supply from the mains power supply directly to the load through the AC bypass; It allows the maintenance of uninterrupted power supply under the continuous power supply of the UPS inverter power supply. Check the operation; when a short circuit fault occurs on the user equipment, the influence of the fault should be reduced to the minimum range.
2 UPS's high immunity to interference increases the availability of LAN equipment
One of the main reasons for the decrease of the "utilization rate" of electrical equipment is electromagnetic interference, which mainly comes from the city's power grid, poorly designed UPS, and in-network electrical equipment.
(2) Classification of UPS
1 Backup Uninterrupted Power System
Backup-type uninterruptible power supply system is a popular UPS power supply that can meet the requirements of general users. Stand-alone output capacity below 3kVA (usually O.25kVA ~ lkVA), when the city power is normal (165V ~ 270V), after the city power through the pressure regulator switch Sl to the load power supply, and floating charge to the battery; when the power When the voltage fluctuation exceeds this range, the inverter circuit is started to convert the DC power of the battery to the AC power output, and the switch S2 supplies power to the load (see Figure 1). Backup UPS has the characteristics of simple structure, low price, low noise, etc. Because it is powered by the mains supply directly to the load, it can not eliminate the electrical pollution such as surge, frequency drift, etc. existing in the mains, and it is suitable for low voltage stability requirements. Occasions.
2 Online Uninterrupted Power System
The inverter of the UPS is always in working condition, and there is no switching time in the inverter. It is suitable for occasions with high requirements for power supply.
3 Online Interactive Uninterrupted Power System
When the mains supply is normal (150V to 276V), the UPS performs the following working process: When the mains is in the range of 175V to 264V, it is supplied to the load via K0 and S1 under the control of the logic circuit; when the mains is in the range of 150V to 175V, Under the control of the logic circuit, K1 is closed, the voltage boosting device will boost the mains voltage (1.10~1.15) times, and the switch S1 will supply the load; when the mains power is at 264V~276V, under the control of the logic circuit, the K2 will be closed and the pressure reducing device The mains voltage is reduced to 0.9 times and the switch S2 supplies power to the load (see Figure 2). Online interactive UPS is an intelligent UPS that can implement a series of automatic detection functions. The online interactive UPS has a shorter switching time compared to the standby UPS and has a lower cost compared to the on-line UPS. Because the battery charging process is implemented by a bidirectional inverter, the charging effect is not ideal, and it is not suitable for a long-delay uninterrupted power supply. In addition, backup or online interactive UPS are all low-end products. Their technical performance is not as high as that of online UPS. When they encounter a rather harsh grid environment, they basically do not have the ability to suppress the transmission of network interference to network equipment.
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