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Theelectromechanical system of expressway consists of four systems, i.e.communication, tolling, monitoring and power supply. It utilizes modernelectronic technology and equipment to realize modern expressway management. Itinvolves multiple disciplines including electronic technology, automaticcontrol, communication technology and computer technology, etc., which istechnology-intensive, high-tech and high-skilled. Among the four systems, powersupply is the basis, communication the pivot, tolling the lifeline andmonitoring the means. Fault and accident in any link of the four systems wouldincur losses upon expressway operation, even shutdown.

   Mostly located in remote areas, expresswayhas to utilize farm-oriented power supply. The power supply condition there ispoor, e.g. big voltage fluctuation, frequent power failure; bad environmentalcondition such as high humidity inside the caves, large temperature differencebetween winter and summer and particularly severe disturbance in thunderstormseasons; weak technical force and poor maintenance capacity, etc. All these posestrict requirements for UPS. For example, UPS should be resistant againstsevere environment and capable of working unattended. In addition, to improvethe stability of the power supply system, expressway design department alsoincreases a parameter voltage stabilizer in front of UPS.

EVADAHQ (3/6/10/15/20/25/30KVA) series UPS adopts the design of on-lineVFI topological structure,which eliminates all kinds of disturbance from the power grid. AC/DC converter usesthree-phase full-bridge rectifying circuit while DC/ACconverter uses SPWM pulse width modulation technology, IGBT power module andoutput isolation transformer so that UPS output is a pure sine wave powersupply with stable frequency and voltage, background noise filtration,resistance against disturbance from power grid fluctuation and low distortion.Meanwhile, the system adopts phase locking synchronization technology anddouble electronic static output switches, whichguarantees UPS causes no disturbance toward backstage load during the switchingoperation between bypass power supply and inverter power supply. This way, UPSalso has good loading capacity, good load compatibility, wide range of inputvoltage and frequency from the mains supply, good generator compatibility andoutput without switch time, etc. Requirements for different applicationenvironments can be well satisfied. Besides, the tiny zero earth voltagedifference meets the power supply demand of precision instruments; the completeprotection system improves the stability and reliability of system operation;the intelligent battery management technology increases the service time of thebattery to a large extent; the user-friendly LCD interface design realizes zerodistance for man-machine communication; UPS and PC can have access to UPS functions(through SNMP) of service history, parameter monitoring, automatic startup& shutdown, unattended and remote network monitoring through RS232communication port, which is suitable for advanced network system.

HQseries UPS has its batteries externally installed. The DC working voltage is192V. Sixteen 12V maintenance-free lead-acid batteries are needed to ensure UPSperforms inversion normally. Meanwhile, suitable battery capacity (Ah) must bechosen according to different back-up time. Then the batteries shall beinstalled by choosing battery cupboards of different specifications according tobattery configuration.

Thisconfiguration is a traditional scheme that has been long used. Its advantage islow purchase cost while the disadvantage is that the reliability is low whileusing single UPS, the distribution system has single point of failure, and theuser’s loading equipment will be directly influenced by the mains supply incase of UPS fault.

Asfor more reliable application, the following series hotbackup configuration can be used. This configuration adopts two HQ UPSs ofthe same capacity. Specifically, one UPS is connected in series to the bypassof the other UPS so as to ensure there is a normal UPS providing stable andclean power supply for the loading equipment when either of the UPSs has faults:

Illustrationof HQ Series Hot Backup Configuration

Forusers depending much on UPS and allowing no power failure, we recommenddigitalized uninterruptible power supply with the function of redundant hot backup.Compared with the system with single UPS, this kind of UPS system with an N+X ACoutput redundant parallel operation is capable of providing higher reliability,stability, maintainability and longer average operation duration withoutfaults. Due to the automatic power distribution, the load applied is betterthan the maximum load allowed by single UPS. The bottlenecks caused by suchfactors as aging component under circumstance of single UPS are prevented. N+Xpower supply: If the user has a power supply load of 20KVA, the reliable methodwill be using 2 UPSs of 20KVA each or 3 UPSs of 10KVA each to realize redundantparallel operation (the number of UPS in parallel is determined by the economiccost). One UPS is automatically isolated after faults; the other UPSs cannormally provide power supply. The UPS with fault can be maintained through thefunction of hot plugging. The recovered UPS cango in parallel on line. This promises the system users extremely high powersupply usability and reliability.

Thedata exchange among the UPSs in parallel of this system is fulfilled through datacable (redundancy) to coordinate their operation status, distribute load evenlyand realize non-master-slave paralleling. 8 UPSs can go in parallel at maximum.

For more detailedinformation, please contact our representative office or our Business Departmentat the Head Office.