Nortel Networks 411-2021-111 manual Power and grounding requirements

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5-2Power and Grounding Requirements

Power and grounding requirements

Typical cell site radio equipment is powered by a +24 Vdc power system. However, the primary power for a DualMode Metrocell is +27 Vdc nominal. The reason that +27 Volts is specified as the nominal voltage rather than +24 Volts is to highlight that the system requires the full float voltage level to enable it to deliver its fully rated available transmit RF output power level. When AC power is lost and the voltage level to the system is reduced to the nominal battery (that is, +24 Vdc), the power amplifiers will automatically step down their transmit RF output power. See the Dual Power Amplifier (DPA) section in NTP 411-2021-113Metrocell Radio Frequency (RF) Frame Description for details.

The power plant normally consists of a negative grounded 12-cell Valve Regulated Lead-Acid (VRLA) battery plant andAC powered battery charging units commonly referred to as the rectifiers. Under normal operating conditions, that is, when AC power is available, the batteries are maintained within their specified float voltage range via the rectifiers which must supply current to power the system and keep the batteries charged. When an AC outage occurs, the battery plant provides back-up power to the system. However, at this time, the system will experience a step drop in voltage due to a battery plant transition from the float state to the fully charged state. During the battery discharge period, the voltage supplied to the system will gradually drop from its fully charged voltage.

Under normal operating conditions an equalizing charge is not required. An equalizing charge is a special charge given to a battery when non-uniformity in voltage has developed between cells. It is given to restore all units to a fully charged condition by using a charging voltage higher than the normal float voltage and for a specified number of hours as determined by the specific voltage used. An equalize charge is also often applied when a recharge of the batteries is required in a minimum time following an emergency discharge.

A typical operating voltage range at the Power Distribution Plant of a Metrocell should not exceed the range between +22.8 Vdc to +29 Vdc. +22.8 Vdc assumes 1 V drop from the batteries to the Rack Interface Panel (RIP) and 0.8 V from the RIP to the load. The operating voltage range of a specific system could vary.

The power plant supplies two (designated as ‘A’ and ‘B’) power feeds to each Metrocell frame. Table 5-1 lists the performance requirements related to primary DC power in a Metrocell.

411-2021-111 Standard 01.01 June 1996

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Contents DualMode Metrocell Page Page Publication history JuneContents Datafilling a Metro Cell Site Power and Grounding RequirementsCell Site Components AppendicesBlock diagram of a 120 Stsr Metrocell using one RF Frame List of tablesPage About this document Intended audience for this publicationHow this publication is organized Applicability of this publicationBand List of termsCarrier RF DBW CellDBm DuplexerIsolation FilterForward path LossDqpsk ModulationOmni Return lossSector Signal RFSectorization Stsr Introduction Northern Telecoms DualMode MetrocellSystem architecture of a DualMode Metrocell Digital ready cellular productBasic components of a DualMode Metrocell Universal CE Frame Metro RF FrameChannel assignment for 800 MHz cellular systems 800 MHz cellular bandChannel assignment Band a 416 channels Band B 416 channels Introduction 6Introduction Standard 01.01 June Omni configuration Cell Site ConfigurationsOverview Sectorized configuration Omni N=7 frequency reuse plan120 N=7 sectorized frequency reuse plan 60 N=4 sectorized frequency reuse plan Omni cell site configuration Cell Site LayoutsControl Channel redundancy RF FrameCell Site Layouts 4Cell Site Layouts Transmit cabling TRU/DPA6Cell Site Layouts No. Receive cablingComponent requirement Frames TRUs ATCsStsr cell site configuration CE Frame Block diagram of a 120 Stsr Metrocell using one RF Frame RF FrameBlock diagram of a 120 Stsr Metrocell using three RF Frames 12Cell Site Layouts DPA 9 Port1 CCH ATC3 Port DPA 10 Port1 14Cell Site Layouts TRU/DPA ATC 16Cell Site Layouts Sector Sector Y Sector ZSector Y TX/RX, 3 RX Sector U Stsr cell site connectionControl Channel Locate Channel Receiver Sector Sector W22Cell Site Layouts Block diagram of a 60 Stsr Metrocell with two RF Frames 24Cell Site Layouts Block diagram of a 60 Stsr Metrocell with four RF Frames 26Cell Site Layouts Transmit cabling 28Cell Site Layouts TRU/DPA 30Cell Site Layouts Port2 ATC3 Port DPA Port1 RF Frame 32Cell Site Layouts Receive cabling 34Cell Site Layouts Sector Y 36Cell Site Layouts Component requirement 38Cell Site Layouts Standard 01.01 June Cell Site Components Major components of a DualMode Metrocell DescriptionNTAX98AA FRU Customer Service Operations 4Cell Site Components Standard 01.01 June Power and Grounding Requirements Safety requirementsPower and grounding requirements Power and Grounding Requirements 4Power and Grounding Requirements Frame power distribution Power distribution for the CE and RF Frames in a MetrocellSystem power protection Grounding UL/CSA approvalCEC par DC coupled signals Cable Identification 10Power and Grounding Requirements Standard 01.01 June Datafilling a Metro Cell Site Datafill OverviewTable Clli Table AcualmMetro RF Frame ATC Alarm PointsCavities Fan Pwr Hsmo +27V a Table VCHINV, CCHINV, Lcrinv Rip Connector J206Port # Frequency Assignment Example Example of Metro TRU datafillExample of Metro ICRM/TRU hardwire configuration Icrm8Datafilling a Metro Cell Site Standard 01.01 June System Configuration Appendix a DualMode Metrocell Cell Site SpecificationsRadio Frequency Alarms Audio InterfacePower Distribution Requirements DC Power RequirementsMechanical Packaging EnvironmentalRadiated Emissions Regulatory Electromagnetic EmissionsTelecom Compliance Product Safety Appendix B Frequency Plans =7 Frequency plan Band a=7 Frequency plan Band B =4 Frequency plan Band a =4 Frequency plan Band B10Frequency Plans Standard 01.01 June Page Cell Site Description
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