UPS / DC Equipment and Battery Rack, Installation and Pre-Commissioning

This article is about UPS / DC Equipment and Battery Rack, Installation and Pre-Commissioning & Requirements of Electrical Power System Systems as per International Codes and standards for Commercial Buildings, Plants and Refinery Projects.

UPS / DC Equipment and Battery Rack, Installation and Pre-Commissioning

Review documentation for the Material Receiving of battery racks for any comments.

Material Inspection

Equipment and Materials shall be new and unused.
Battery rack and Equipment shall be in accordance with the Saudi Aramco-approved project-specific design drawings, diagrams, schedules, lists, databases, and associated design documents.

Battery Racks Installation

“For Valve Regulated Batteries:
a) Rack Construction
The modular battery rack shall be welded steel units containing a maximum of 6 cells per unit. Each module shall be designed to allow air circulation between individual cells to maintain uniform cooling of each cell. Alternatively, if a stackable battery rack-type is not available as a standard product, racks shall be constructed of welded or bolted structural steel frames with bolted steel runners and braces, and with provisions for anchoring to the floor.
”
“b) Rack Design
The modular rack design shall allow easy installation or removal of individual cells from any module without disturbing the modular rack assembly. Standard battery rack as specified in Sec. 11.1.1 shall be acceptable as well since it facilitates removal and/or installation of batteries.
”
“Stack Height
The vertically stacked height of valve regulated batteries shall not exceed 1700 mm above the floor. VRLA battery mounting on a standard rack shall be allowed with its shall not exceed 1700mm.
”
“c) Painting
All metallic components, excluding hardware and grounding connectors, shall be coated with an acid resistant baked powder epoxy or propylene or acid resistant plastic coating. Vendor shall supply a sufficient quantity of field-applied coating for touching up scratches.
”
“For Vented Lead-Acid & Nickel-Cadmium Batteries:
a) Rack Construction
Racks shall be constructed of welded or bolted structural steel frames with bolted steel runners and braces, and with provision for anchoring to the floor and grounding.
”
“b) Rack Design
Battery rack shall consist of up to 2 steps, and each step shall have only one row for the ease in maintenance. The maximum height from the floor level to the top terminal of the upper battery shall be 1700 mm, which may allow up to 2 tiers rack.
”
All metallic rack components that are in contact with the battery shall be insulated by removable covers or the rack shall be plastic coated.
“c) Painting
All metallic components, excluding hardware and grounding connectors, shall be coated with an acid resistant baked powder epoxy or propylene. Racks for nickel-cadmium batteries shall be coated with alkali-resistant coating. Where applicale, Vendor shall supply a sufficient quantity of field-applied coating for touching up scratches.
”

Paralleling up to 4 sets of battery strings of identical Ah capacity and potential shall be allowed, to achieve required Ampere Hour capacity.
All connections shall be bolted to the cell posts. All cell-to-cell connections in the same row shall be made by plated copper bus bars using 316 stainless steel hardware or nickel plated copper or equivalent. Tier-to-tier connections shall be made by insulated copper cables with 316 stainless steel hardware or nickel plated copper or equivalent. The cell-to-cell interconnecting hardware shall be sized to allow discharge current at the 30-minute rate with no more than 15 mV drop between adjacent cells. The inter-cell connectors shall withstand the available short circuit current without damaging the unit. Insulated copper busbars or covers for the inter-cell connecters and the terminals shall be supplied with the batteries.
All nuts, bolts, washers, and similar hardware shall be 316 stainless steel or nickel plated copper or equivalent.
Battery enclosures for indoors mounting: Battery enclosures and cell supports shall be free-standing and made of fiberglass reinforced material or steel and conforming to NEMA250, Type1, or IE C60529 IP21. The enclosures shall have suitable ventilation, and provisions for anchoring to the floor and grounding.
Battery enclosures for outdoors mounting: Shall be completely weather-proof, dust-tight and rain-tight. Minimum enclosure protection class shall be NEMA250, Type4, or IEC 60529 IP65. The battery enclosures shall be made of fiberglass-reinforced material, with suitable ventilation and provisions for anchoring to the floor and grounding.
Replacement cells shall be provided with terminal grease, cell connectors, and connection hardware. Covers for the inter-cell connecters and terminals shall be provided with the batteries.
Circuit breakers or load disconnect switches shall be provided at the output of each UPS module for the purpose of isolating either or both UPS units from the load bus.
Batteries shall be either flooded (vented) type or valve regulated type in accordance with the requirements of Saudi Aramco Materials System Specification 17-SAMSS-511. But using valve regulated lead acid batteries requires prior concurrence form Saudi Aramco End User and the Manager of CSD.
The battery shall be protected by a fused disconnect switch or a DC circuit breaker, which shall be equipped with auxiliary contacts to provide an alarm when the DC circuit is open.
“The following shall be individually protected:
a) AC Input to the rectifier/charger: by circuit breaker(s) or fuse(s)
b) Battery disconnect: by fused disconnect switch or DC circuit breaker and shall have a facility to disconnect the battery from supplying its load upon reach of cell end of discharge voltage.”
Valve-regulated batteries shall not be used in locations where the average ambient temperature may be higher than 25°C.
Substation battery systems shall be dedicated to connected DC load and shall not be part of a plant UPS or other DC system.
The minimum number of series-connected cells shall be in accordance with Table 2:

Working space of at least 1 meter shall be provided in front of each battery rack or enclosure.
Batteries shall be supplied with covers for all inter-cell connecters and terminals or insulated copper busbars to enhance safety.
Battery rooms shall be vented to the outside air by forced ventilation to prevent accumulation of hydrogen and to maintain design temperature. The ventilation system is determined such that the hydrogen concentration shall be limited to less than 1% of the total air volume of the battery room.
Equipment with arcing contacts shall be located in such a manner as to avoid those areas where hydrogen pockets could form. Electrical equipment shall not be located directly above the batteries and, as a rule, shall have a minimum horizontal separation of 1.5 meters from the nearest cell. Commentary Note: It is recommended that all electrical devices with arching contacts (such as lighting switches) be installed outside the battery room as practically possible.
Temperature in the battery room shall be maintained at, but shall not exceed, 25°C.
Battery racks gounding and bonding shall be in accordance with SAES-P-111 and NEC 250 or EN 50178.
Stationary batteries shall be installed on open battery racks within a battery room to facilitate proper cooling, routine inspection, and maintenance.
Covers for all inter-cell connecters and battery terminals or insulated copper busbars shall be supplied as part of the battery to enhance safety.

International Standard and Codes for Battery Rack

3. NFPA 70 National Electrical Code (NEC), 2008 Edition
4. SAES-P-103 UPS and DC Systems, 02 June 2008
5. 17-SAMSS-511 Stationary Storage Batteries, 17 July 2007
6. 17-SAMSS-516 Uninterruptible Power Supply System, 13 August 2007