IEC 60255-127:2010 pdf – Measuring relays and protection equipment – Part 127: Functional requirements for overlunder voltage protection.
4.5.2 Operate (trip) signal
The operate signal is the output of measuring and threshold elements, alter completion of any intentional operating time delay. In the case of instantaneous elements, this signal may occur at the same time as the start signal (if provided).
4.5.3 Other binary output signals
If any other binary output signals are available for use, their method of operation shall be clearly shown on the functional logic diagram. Additional textual description may also be provided if this can further clarify the functionality of the output signal and its intended usage.
5 Performance specification
5.1 Accuracy related to the characteristic quantity
For both independent and dependent time relays, the accuracy and the reset ratio related to the characteristic quantity shall be declared by the manufacturer.
For both dependent and independent time relays, the manufacturer shall declare the accuracy related to the characteristic quantity along with a setting value range over which it is applicable.
5.2 Accuracy related to the operate time
For independent time relays, the maximum permissible error of the specified operate time
shall be expressed as either:
• a percentage of the time setting value, or:
• a percentage of the time setting value, together with a fixed maximum time error (where this may exceed the percentage value), whichever is greater. For example, ±5 % or ±20 ms whichever Is greater, or:
• a fixed maximum time error
For dependent time relays, the reference limiting error is identihed by an assigned error declared by the manufacturer. For relays with a decreasing time function, the value of the assigned error shall be declared at the maximum limit of the effective range of the dependent time portion of the characteristic (G0) as a percentage of the theoretical time. The reference limiting error shall be declared either as:
• a theoretical curve of time plotted against multiples of the setting value of the characteristic quantity bounded by two curves representing the maximum and minimum limits of the limiting error over the effective range of the dependent time portion of the characteristic or.
• an assigned error claimed for the effective range of the dependent time portion of the characteristic of the characteristic quantity.
For both dependent and independent time relays, the manufacturer shall declare the maximum limiting error related to the operate lime along with a setting range of time delay over which it is applicable.
The manufacturer shall declare If the Internal measurement time of the characteristic quantity and the output contact operation time is included in the time delay setting or it is in addition to the time delay setting.
5.3 Accuracy related to the reset time
For relays with no intentional reset delay, the manufacturer shall declare the reset time of the element, For relays with a definite time delay on reset, the maximum permissible error of the specified reset time shall be expressed as either;
• a percentage of the reset time setting value, or;
• a percentage of the reset time setting value, together with a fixed maximum time error (where this may exceed the percentage value), wt’iichever is greater. For example, ±5 % or ±20 ms whichever is greater, or;
• a fixed maximum time error.
The manufacturer shall declare the maximum limiting error related to the reset time along with a setting range of time delay over which it Is applicable.
The manufacturer shall declare ii the internal measurement time (disengaging time) is included in the reset time setting or it is in addition to the reset time setting.
5.4 Transient performance
5.4.1 Overshoot time
The manufacturer shall declare the overshoot time.
5.4.2 Response to time varying value of the characteristic quantity
To ensure proper coordination with dependent time relays, the relay performance under time varying fault conditions (characteristic quantity varies with time) shall be tested. The manulacturer shall declare any additional errors, but in all cases, the additional error shall be less than 15%.
5.5 Voltage transformer requirements
The manufacturer shall declare the types of the voltage transformers required to maintain the claimed performance levels (refer to IEC 60044 series standards).
6 Functional test methodology.