Standards Development

Scope

This part of IEC 63222 specifies requirements for estimation of power quality events influence zone over public power supply network at high voltage, medium voltage and low voltage with nominal frequency at 50Hz or 60Hz.

The power quality events in this document refer to discontinued phenomena defined in IEC TS 62749, e.g. voltage dips,voltage swells and voltage short -time interruptions, but fast time domain events and transient over-voltage events are excluded.

The boundaries between the various voltage levels can be different for different countries or regions. In the context of this document, the following terms for system voltage are used:

– low voltage (LV) refers to UN ≤ 1 kV;

– medium voltage (MV) refers to 1 kV < UN ≤ 35 kV;

– high voltage (HV) refers to 35 kV < UN

Because of existing network structures, in some countries or regions, the boundary between medium and high voltage can be different.

NOTE 1 Time domain analysis is not included in this document.

Purpose

With the development of modern electric power system, more and more power -electronic interfaced equipment/installations are integrated to power system,like renewable energy generations,EV chargers, energy storage,VSD(variable speed drive),etc,power grids b ecome more and more flexible and compatible. However, in the other hand, power -electronic based interfaces are ‘sensitive’ to power quality disturbances, especially to power quality events like voltage dips,swells and short time interruptions, they may lead frequent malfunctions of electrical equipment in industrial and commercial installations (e.g., adjustable -speed drives, process-control equipment, relays,contactors and computers). The economic impact of events is often expressed in millions (or even billions) of funds per year.

In the past, once the events happened, the post-events analysis will be carried out and corresponding measures will be taken for remediation. Nowadays,customers with important and sensitive loads may demand from their distribution companies detailed data s howing the information of outages, interruptions and voltage dips that should be expected at various locations in the network for taking proactive and comprehensive approach at planning/design stages to prevent the expected cost of failures. It could also guide the choice of location for new plants, the selection of manufacturing equipment or suggest the purchase of custom power devices.

Standardization on issue of analysis on events influence zone over public supply network is developed accordingly. Events influence zone, defined as area or distance from the event source in which the supply voltage may exceed the predefined voltage thresh old in case of event happened,provides full picture demonstrating event propagation,residual voltage level at different phase,etc., serving for market requirements.