IEC/TS 62898-3-3 Ed. 1.0 en:2023

This part of IEC 62898 deals with frequency and voltage stabilization of AC microgrids by dispatchable loads, which react autonomously on variations of frequency and voltage with a change in active power consumption. Both 50 Hz and 60 Hz electric power systems are covered.

This document gives requirements to emulate the self-regulation effect of loads including synthetic inertia.

The loads recommended for this approach are noncritical loads, this means their power modulation will not significantly affect the user as some kind of energy storage is involved which effectively decouples end energy use from the electricity supply by the electric network. The self-regulation of loads is beneficial both in island mode and grid-connected mode. This document gives the details of the self-regulation behaviour but does not stipulate which loads shall participate in this approach as an optional function.

This document covers both continuously controllable loads with droop control and ON/OFF-switchable loads with staged settings. The scope of this document is limited to loads connected to the voltage level up to 35 kV. Reactive power for voltage stabilization and DC microgrids are excluded in this document.

NOTE 1 If agreed between system operator and grid user, the self-regulating principles outlined in this document can also be applied to loads in other electricity networks, see IEC/ISO Directives, Part 1:2023, C.4.3.2, Example 1.

NOTE 2 According to 3.1.7, critical loads with an electrical energy storage system such as an uninterruptable power supply are considered as noncritical and therefore dispatchable.