Home>IEC standards>IEC 60255-149-2013 pdf download

IEC 60255-149-2013 pdf download

IEC 60255-149-2013 pdf download.Measuring relays and protection equipment – Part 149: Functional requirements for thermal electrical relays.
4 Specification of the function
4.1 General
An example of a thermal protection function with its input energizing quantities, binary input signals, operate (trip), alarm and other binary outputs, and functional logic which includes measuring element, thermal level calculation, settings, and thresholds are shown in Figure 1.
The manufacturer shall provide the functional block diagram of the specific thermal protection implementation.
4.2 Input energizing quantitieslenergizing quantities
The input energizing quantities are the measuring signals, such as phase (or line) currents, and ambient/environmental or winding temperatures (if required or applicable). Their ratings and relevant requirements are specified in IEC 60255-1.
Input energizing quantities can be presented to the thermal protection functional logic either hardwired from current transformers and any additional input quantities such as ambient or winding temperature, or as a data packet over a communication ports using an appropriate data communication protocol, such as IEC 6 1850-9-2.
The input energizing quantities used by the thermal protection function need not be the current directly taken from the secondary side of the current transformers. Therefore the protection relay documentation shall state the type of energizing quantities used by the thermal protection function.
Examples of input energizing quantities are:
— single-phase current measurement;
— three-phase current measurement;
— positive and negative sequence current measurement;
— winding or ambient temperature sensor.
NOTE The ambient temperature, coolant temperature, top oil temperature or winding temperature of the equipment to be thermally protected can be measured by temperature sensors, such as resistance temperature detector (RTD), the values of which can be used for biasing the calculation of the thermal level replica specified in this standard, Output signals or values of these temperature sensors can be taken into account for the first-order thermal model algorithm, which can influence and compensate the calculated thermal level (based on the equivalent heating current and heating thermal time constant values).
4.3 Binary input signals
If any binary input signals (externally or internally driven) are used, their influence on the thermal protection function shall be clearly described on the functional logic diagram or in the protective device manufacturer documentation. Additional textual description may also be provided if this can further clarify the functionality of the input signals and their intended application or implementation.IEC 60255-149 pdf download.

Related PowerPoint Templates

Template Categories