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Circa 20 years ago, a large amount of small and medium distributed DC power systems were deployed in BT's UK fixed network. There is an aspiration to replace rectifiers used in the power systems with modern high efficiency products, but how to make it a good business case? BT in partnership with Huawei has devised a solution that achieves a 3 years ROI with many novel rectifier replacement techniques.
Two voltage levels of High voltage Direct Current (HVDC) systems in China are discussed in this paper. Their rated voltage are 240V and 336V (corresponding working voltages are 276V and 380V). After introducing the principle of the HVDC system, we reviewed the main characteristics \including the voltage ranges, system reliability and maintainability of HVDC system. As large quantity of 240V HVDC systems...
The explosive growth of mobile applications requires more bandwidth, which, in turn, requires more energy as well as additional investments in network infrastructure-money that service providers must find ways to recover.
We present a quantitative analysis of the benefits of the 380 VDC power distribution system compared to the current −48-VDC power supply system. The analysis is based on models of typical distribution configurations in global telecommunication sites and takes into account codes, regulations, and practices for wiring and voltage drop comparison between centralized/decentralized 48- and 380-VDC. In...
A consideration of short-circuit protection in high voltage direct current (HVDC) distribution system is written in this paper. There are some types of energy sources in HVDC system, and the behavior of short-circuit current is affected by the way to rectify. Therefore, it may be more complicated to protect short-circuit in HVDC system than it is in AC system. In this study, a protection technique...
Thermal runaway scares the heck out of many people; especially those that do not know how to detect that the conditions are being set for a thermal runaway. While thermal runaway can occur in most battery chemistries such as lead acid either VLA or VRLA, or Ni-Cad, or Lithium Ion, this paper is going to restrict itself to the VRLA technology.
Battery and DC power system assets management is a critical and important part of any operating Telco's service reliability and availability plans. This needs to be addressed within tighter constraints on CAPEX for assets that don't directly generate revenue and in an environment of an aging infrastructure.
Telecommunication operators must manage many types and models of power equipment from many manufacturers each with different characteristics. With Telco's globally reporting strong pressure on CAPEX reduction, it is important to develop capability not only of predicting end-of-life of equipment, but also of managing the vast number of types, makes and models used in a variety of environments. Delayed...
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