IEEE Std 1115 pdf free download

IEEE Std 1115 pdf free download.Sizing Nickel-Cadmium Batteries for Stationary Applications.
3. Definitions
For the purposes of this document, the following terms and definitions apply. The IEEE Sianclarcl.c
Diciionari’ Online should be consulted for terms not defined in this clausc.3
available capacity: The total ampere-hours or watt-hours that can be withdrawn from a cell based UOfl a specific set of operating conditions (including initial state-of-charge, dischargc rate, initial ccli temperature. and end voltage) and the state of health of the cell.
battery duty cycle: The sequence of loads a battery is expected to supply for specitied time periods.
float service: Operation of a dc system in which the battery spends the majority of the time on float charge with infrequent discharge. Syn: standby service.
period: An interval of time in the battery duty cycle during which the current (or power) is assumed to be constant for purposes of cell sizing calculations.
rated capacity: The capacity assigned to a cell by its manufacturer for a given discharge rate, at a specified electrolyte temperature, to a given end-of-discharge voltage.
standby service: See: float service.
state of charge (SOC): The stored or remaining capacity of a battery expressed as a percentage of its fully charged capacity.
4.2.4 Other considerations
The lists of typical loads appearing in 4.2.2 and 4.2.3 are not a full catalog of the dc loads at any particular installation. Loads applied to the battery are normally typed as constant power, constant resistance, or constant current. However, for sizing purposes. loads are treated as constant power or constant current. The designer should review each system carefully to be sure all possible loads and their variations are included (see Annex B).
4.3 Duty cycle diagram
4.3.1 General
A duty cycle diagram showing total load at any time during the cycle is an aid in the analysis of the duty cycle. To prepare such a diagram, all loads, expressed as either power or current expected during the cycle, are tabulated along with their anticipated inception and shutdown times. The total time span of the duty cycle is determined by the requirements of the installation.
4.3.2 Known loads
Loads that have inception and shutdown times that are known arc plotted on the duty cycle diagram as they would occur, lithe inception time is known but the shutdown time is indelinite, it should be assumed that the load will continue through the remainder of the duty cycle.
4.3.3 Random loads
Noncontinuous loads that occur at random should be shown at the most critical time of the duty cycle in order to simulate the worst-case load on the battery. To determine the most critical time, it is necessary to size the battery without the random load(s) and to identify the section of the duty cycle that controls battery size. Then the random load(s) should be superimposed on the end of that controlling section. as shown in Figure 1 (see also 6.5.5).
5.2 Cell performance
All nickel-cadmium cells used in applications covered by this recommended practice are categorized by different performance types, generally determined by plate thickness. Generally, high-rate cells (with thin plates) are used for loads requiring high-discharge currents of short duration. Low-rate cells (with thick plates) are used for loads of long duration. Medium-rate cells (with medium plate thickness) are used for loads requiring combined performance. Any performance type can be utilized for any of these load requirements, but generally the economics will determine the correct type to be used. The different performance types are defined in IEC 60623 [B2].5 Cells designed for use in float operation are either vented or fitted with low-pressure valves. Hermetically sealed cells of the type used in portable appliances are not suitable for operation with constant potential chargers (see 6.4).IEEE Std 1115  pdf download.