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Network remote power feeding provides energy to telecommunications equipment over existing conductors normally used to transport data. Existing and emerging applications for remote powering are discussed along with the safety aspects, standards and limitations of using signal lines at elevated voltages. Finally the added capabilities of a new “digital” power distribution technology known as “Packet...
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.
Stationary battery energy storage systems are widely used for uninterruptible power supply systems. Furthermore, they are able to provide grid services. This leads to rising installed power and capacity. Lead-acid batteries provide one of the most mature and economically feasible solutions. Although this technology has been known and studied for more than 100 years, a further understanding of the...
Ohmic measurements (Conductance, Impedance, Resistance) have been in use in telecommunications networks for battery state of health assessment since the 1980s. The technology hasa track record of effectiveness and is an efficient tool for as part of an overall battery maintenance program, providing cost and time savings and advance warning of battery degradation in key systems.
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.
This paper addresses the reliability and availability of uninterruptable power supply systems (UPS) used in modern datacenters and telecom core infrastructure. As 380V DC power distribution systems are gaining wider acceptance, it is expected that they meet high standards imposed by the industry in terms of reliability and availability. In this paper, reliability and availability of AC UPS topologies...
With the development of telecom industry, the solution of energy saving and CO2 emission reduction ha become a hot topic since competitiveness and socia responsibility is more and more important. According to data statistics, cooling system has consumed up to 50% of tota energy consumption to maintain battery temperature at around 25°C by air conditioner.
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...
With the advent of increasing energy cost from the grid, need to go were no grid is or having to rely upon no grid, we have seen the emergence of hybrid solutions. With the beginnings of these new solutions, we see different business objectives, customer service expectations, municipal limitations and neighbourhood conditions that vary from carrier, region, site, et cetera. The result is that hybrid...
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.
This paper describes a molded-cased circuit breaker (MCCB) for higher voltage direct current (HVDC) power feeding systems. To protect circuits from fault current, such as an overcurrent or a short circuit current, an overcurrent circuit breaker is installed in power feeding systems. When a large-scale overcurrent circuit breaker is required, the case which uses MCCBs in HVDC power feeding system can...
Sodium Nickel Chloride Batteries for stationary applications have demonstrated to be effectively used for high energy density deployment in telecom facilities. This paper reviews the characteristics of Sodium-Chloride batteries and describes the installations in telecom facilities.
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.
This paper presents a reconfigurable solar photovoltaic (PV) battery charger. A traditional PV charger either utilizes a DC/DC converter between the PV array and load, or it connects the battery directly to the PV array without any power conversion. Different from these approaches, our proposed PV charger avoids conventional DC/DC converters by using a reconfigurable switch matrix. This switch matrix...
The aim of a new site solution concept (i-Site) has been to optimize energy costs, speed of deployment, and site equipment such as number of PV modules. The present study provides the first example of a Life Cycle Assessment (LCA) quantifying the future environmental benefit of i-Site for support of a radio base station in South African Vodafone network. This study will moreover show the business...
After a stationary battery has reached end-of-life or is no longer required for use, it must be carefully managed and steered through a mandated disposal and reclamation process. The failure to do this, can cause the owner to fall foul of several regulatory requirements that may result in various legal actions resulting in heavy fines or even imprisonment. In most cases, the owner is deemed to be...
The continuous increase in fuel costs for generators is driving organizations that use power in off-grid locations to search for more cost-effective ways of powering their sites. This is especially the case within the telecoms sector where grid supply is unreliable. Therefore, choosing a reliable method (including equipment) to generate electricity to run sites is vital to successfully operate equipment.
With over 20 years of continuous monitoring of batteries, archival of a trillion points of data, timelines, and trends of over 1.2 million battery units, we are finding some common aging history.
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