IEEE Std 937-2019 pdf download

IEEE Std 937-2019 pdf download.IEEE Recommended Practice for lnstallation and Maintenance of Lead-Acid Batteries for Photovoltaic (PV) Systems.
b) In the case of rack mounting, completely assemble and tighten rack fasteners before loading cells, and load in accordance with manufacturer’s recommendations.
c) Prevent impact of cells to avoid damage.
d) Confirm that all cell openings arc capped.
c) Avoid excessive tilting of vented cells that could result in electrolyte spillage.
4.3.6 General
The following are general safety precautions:
a) Establish unobstructed egress from the battery area.
b) Prevent unauthorized access to battery area.
c) Keep the top of the battery clear of all tools and other foreign objects at all times.
5. Installation design criteria
5.1 Introduction
Considerations that should be included in the design of a photovoltaic battery installation depend upon the requirements, function, and size of the system of which the battery is a part. General criteria for all photovoltaic battery installations are described in 5.2 through 5.5.
5.2 Enclosure
5.2.1 Introduction
Batteries should be protected by means of a suitable enclosure, which may vary from a box to a room. The enclosure should be clean, dry, adequately ventilated, and provide and maintain protection against detrimental environmental conditions.
5.2.2 Location
The following should be considered when deciding on the location of the battery enclosure:
a) The battery enclosure should be located as close as practical to the photovoltaic array, loads, and power conditioning equipment. consistent with item e) of 5.4.
b) The enclosure location should provide adequate structural support, and be as free of vibration as practical.
c) The battery location should preclude contamination of water supplies and damage to equipment in the event of electrolyte spillage.
d) The enclosure location should be readily accessible to emergency response personnel.
5.2.3 Mechanical considerations
The following mechanical aspects should be considered during the design or selection of the battery enclosure:
a) The size of enclosure should allow for sufficient clearance around the battery to provide access for installation and maintenance. Consideration should he given to the space required for safety and handling equipment (sec 4.2).
b) The surface on which the system is mounted should be adequate to support the weight of the battery and its enclosure.
c) The enclosure should be resistant to the effects of electrolyte, either by selection of materials used or by appropriate coatings. Provision should be made for containment of any spilled electrolyte per appropriate codes and regulations.
d) Any enclosure doors should allow unobstructed egress.
e) The enclosure design should include appropriate means to prevent unauthorized entry.
5.2.4 Environmental considerations
The following environmental aspects should be considered during the design or selection of the battery enclosure:
a) The enclosure shall be ventilated, either by natural or induced means, to prevent the accumulation of an explosive hydrogen mixture, and to limit the accumulation of other hazardous gases. The hydrogen concentration shall be limited to less than 2% by volume. The enclosure design should either avoid creation of difficult-to-ventilate areas, including false ceilings, or make adequate provision for their ventilation. The amount of hydrogen released is typically very small under most conditions, and no extra mechanical ventilation is usually necessary if the battery enclosure is not completely Thealed.” See IEEE Std 1635Th1 [B5] for further information and expected hydrogen gas release.
b) To prevent battery damage, the enclosure should be designed to maintain the electrolyte temperature above its freezing point. The temperature at which the electrolyte will freeze for a given battery state of charge and operating-specific gravity may be obtained from the battery manufacturer. Extremely high electrolyte temperatures may cause excessive water usage and may damage the battery. Battery manufacturers may recommend a maximum operating temperature for their batteries.
c) A cell electrolyte temperature of 25 0Q is normally the basis for rated performance in North America. A location where this temperature can be maintained at or below this level should contribute to optimum battery life. Either passive or active means to reduce temperature excursions from 25 °C should he considered. Passive means can include partial burial of enclosures, color of exterior finish, and insulation. Active means can include forced-air ventilation.
NOTE- If the electrolyte temperature varies from optimum, sizing may be atlected.
d) Temperature differences between cells within the battery should he limited to 3 °Q. Localized heat sources, including direct sunlight, radiators, steam pipes, and space heaters should be avoided.