Hands-On Central Office DC Power & Grounding On-Site or Virtual Live Instructor-led

Course Description

This extensive 2-day "Live" Instructor-Led (On-Site or Virtual) course is designed for Central Office Technicians or others with the responsibility for the installation, maintenance, troubleshooting, and repair of Central Office power equipment. NEW material has been added to reflect some of the latest tools available, including automatic power monitoring, infrared cameras, battery testers, plus sodium nickelchloride batteries.

The course provides a broad but detailed study of Central Office power systems, for both earlier and modern equipment. The course can also offer material on Data Center power, which typically uses AC-powered servers that are increasingly being used by telcos and service providers.

Basic electrical theory is effectively combined with a practical hands-on approach that enhances the students' learning experience. Examples include DC wattage versus reactive volt-amps, and how this affects surge currents and AC ground loops. Use of various testing equipment is demonstrated, showing how different vendors offer similar features. Multiple types of measurements are shown, including the use of DC current meters, battery resistance meters, ground field resistance meters, and automatic measurements made using continuously-monitored battery and power systems, showing on-demand measurements and trends.

Examples are shown for a typical central office with both earlier DC rectifier, battery, and BDFB components, plus newer systems that integrate some or all of these components. A remote equipment cabinet example is also shown, showing options for site grounding, including grounding that is coordinated with the power company.

The course can be adjusted to suit the needs of a given group, including grounding of outside-plant copper and fiber optic cables, and grounding at the customer premise, like shields, messenger leads, and tracer leads, plus sizing of the conductors and minimum length of the ground bar. Grounding to other metallic structures like fences, towers and nearby plant can also be included.

Students Will Learn

CO Power concepts including electrical fundamentals of L, C R
Ground Return Paths - How DC AC grounds are the same
Disconnects - AC DC interrupts to halt current flow
Breakers Fuses - including primary 'tell-tale'
DC Wiring Schemes - AB Feeds, Wire Gauges, Fuse Selection
Batteries Their Connections - including chemistries, charging vs. equalizing
DC Rectifiers - traditional vs. switching designs, features, load-sharing
DC Grounding zones - bus bar types, isolatedIGZ, etc.
DC volt ammeters - high-current, clamp-on vs. in-circuit
Dangers - including high-amperages, open circuits, loose connections, margins
Test Maintenance - battery maintenance, ground field, battery strap drop, etc.
Troubleshooting with previous examples
Telcordia, NESC and NEC best practices and requirements
And much more

Target Audience

Vendors and telecommunications personnel (incl. engineers, planners, supervisors and technicians) who
are responsible for Central Office equipment installation, maintenance, troubleshooting repair.

Prerequisites

None. A basic understanding of electrical concepts, telecommunications equipment terminologies and
OSP Bonding Grounding may be helpful.

Course Outline

Module 1 : CO Power Concepts

Safety - What Could Go Wrong?
What Exactly Is Ground?
Ground as A Conductor
Voltage Potential: AC & DC Voltage
Ohm's Law
Series & Parallel Circuits
Reactance: Capacitance, Inductance
Impedance
   - Resistance vs. Impedance
   - Power: Watts vs. Volt-Amps
   - Power Factor
   - Surge Current
Decibel Measurements
   - dBrn & electrical Noise

Module 2 : AC Power & Grounding

Commercial AC (supporting DC systems)
Conventions:
   - Single-Phase & Three-Phase
   - Wye & Delta Inputs
   - Multi-Grounded Neutral (MGN)
Power Conversion
   - Rectification
   - Peak-to-Peak, Average, RMS
Ground Potential Rise (GPR)
Disconnects
Surge Arrestors
Generator Transfer Switch
Rectifier Comparison:
   - early (non-switching) conversion
   - switching (early, modern, full-featured with monitoring)
   - settings: float, equalize, LVD, walk-in, surge current
Inverters:
   - functions, efficiency
   - configurations for redundancy
Examples
Exercise

Module 3 : DC Power Components

CO DC Components
   - Rectifier, Charge Bus, Discharge Bus, Battery String, Power Board, Inverter
   - Points of Failure
Rectifier Operation
   - Non-Switching vs. Switching Comparison
   - Review of Rectifier Types
Negative Voltage Systems
   - Wiring Conventions
Battery Types
   - Wet Cell: LA, LC, VLRA, NaNiCl
   - AGM
DC Power Boards
   - Main Disconnect, LVD, Shunt, meters
   - A&B distribution
DC Power Distribution
   - primary & secondary distribution buses
   - BDFB
   - bar types - Cu vs. Al, coated vs. non-coated
Fuse & Breaker Types
Wire Derating Charts
Testing
   - Reconciling Currents - potential & return leads
   - Voltage Drops: battery-to-power board, to equipment
   - How to take a measurement
Examples
Exercise
(Optional: DC-AC Inverters for Video Head-End or Data Center Servers)
(Inverter examples, redundancy configurations incl. cost vs. benefit, surge & efficiency specs)

Module 4 : Bonding & Grounding

RUS, AT&T, other standards
Ground Bar Types: MGB, OPGP
Wiring
   - RUS: PANI, CEGB, FGB, GWB, IGZ, etc.
   - AT&T: OPGP, CVGB, COGB, MGB, IBN, etc.
Isolated Grounds
   - Ground Window Theory: when and when not required
   - Noise fault locating, mitigation
Grounding Rods
   - size, depth, angle
   - chemical grounding (GEM, ground wells)
Bonding Methods
   - Exothermic Welds
   - Compression/Crimp Connection
   - other connection types
Grounding Standards:
   - Remote Site Example, MGE ground options
   - Ground cable types: cable-entrance, AC pedestal/MGN, DC equipment, etc.
   - Grounding at the Prem: ground bar depth, ground cable sizing
Measurements
   - OSP cable shield
   - Ground Field Resistance: multiple-electrode fall-of-potential & clamp-on meters
Exercise
(Optional: Customer Premise Grounding Examples: aerial or buried ground, detached-home
BET, trailer park, telco & power company grounds, citations from agencies like
the NEC/NESC/CFR, etc.)
(Optional: MTSO antenna tower grounding, fence and hut grounding)

Module 5 : CO Power-Related Routines

Battery String Maintenance
   - Specific Gravity, electrolyte level, voltage measurements
   - Frequency, common problems & solutions
   - Strap Continuity Test example
Rectifier & Powerboard
   - Voltage & Current Readings
   - Automatic power monitoring (Alpha Cordex example)
   - Floating vs. Equalizing
   - Common problems & solutions
Breakers & Fuses
   - Primary vs. GMT tell-tale
   - Oxidized or current-inhibiting contacts
   - Possible problems
Smoke & Fire Prevention
   - Symptoms - What to do
   - Firestopping
   - Causes of previous fires
Equipment List
   - Calibration vs. equipment that cannot be calibrated
   - Digital Multimeters: minimum capabilities, tolerances, data-logging
   - Ground Field Resistance Testers
   - Specific-Gravity/Hydrometer/Battery Density testers
   - Battery Internal Resistance Tester
   - Infrared Camera
Battery & Power System Monitoring
   - per-cell & system measurements
   - on-demand & trend measurements (Generex BACS & Emsys examples)
   - alarm history
(Optional: Power Monitoring System In-Depth Example: Enersys, Generex, Benning, etc.)

Module 6 : Power & Grounding Terms
Glossary & Dictionary of Terms
Regulatory & Standards Agencies (US)
Regulatory & Standards Agencies (Canada)
Metric Prefixes

Notes

This course is standard 2 Days but can be extended to a 3 Day course dependent on course options and lab requirements upon request.

Delivery Method

On-Site or Virtual Live Instructor-led with numerous labs and exercises.

Equipment Requirements
(This apply's to our hands-on courses only)

BTS always provides equipment to have a very successful Hands-On course. BTS also encourages all attendees to bring their own equipment to the course. This will provide attendees the opportunity to incorporate their own gear into the labs and gain valuable training using their specific equipment.

Course Length

2 Days