IEC/TR 63282 Ed. 2.0 en:2024

LVDC systems - Assessment of standard voltages and power quality requirements

IEC TR 63282:2024, which is a technical report, collects information and reports experience for the standardization of voltage levels and related aspects (power quality, EMC, measurement, etc.) for LVDC systems (systems with nominal voltage up to and including 1 500 V DC).

Rationale for the proposed voltage values is given. Variation of parameters for the voltage (power quality) for their boundaries are defined. Nevertheless, some of the technical items are not exhaustively explained in this document and some gaps are identified for future work.

Attention is paid to the definition of DC voltage.

Systems in which a unipolar voltage is interrupted periodically for certain purposes, e.g., pulse voltage, are not considered.

Traction systems are excluded from this document.

This document gives technical inputs to TCs in charge of the standardization of different issues and coordinated by SyC LVDC.

This second edition cancels and replaces the first edition published in 2020. This edition constitutes a technical revision.

This edition includes the following significant technical changes with respect to the previous edition:

• a) Optimized terms and definitions in Clause 3: DC system nominal voltage is modified. Oscillation is added. Active distribution system, passive distribution system are deleted.
• b) Modified the definition of voltage bands: In Clause 5, the definition of voltage limits in voltage bands is added, from U1 to U6. The definition of voltage bands, from B4 to B7, is modified.
• c) Distinguished the difference between oscillation and power quality phenomenon: In Clause 3, the definition of oscillation is added based on IEV 103-05-04. In 6.3, relationship between oscillation and power quality is clarified. Annex B gives a LDC oscillation typical example which has really happened in a MV&LVDC system in China.
• d) Modified the recommended voltage for distribution DC network: The factors considered in voltage values definition is clarified. And the voltage is divided in two domains, distribution domain and installation domain. The voltage recommendation in LVDC is listed corresponding to voltage bands.
• e) Modified the voltage immunity level assessment: It is mentioned in 7.2 that the assessment of voltage immunity levels of mass LVDC power electronic devices need to be further discussed, ripple as an example is introduced.
• f) Added DC power quality measurement methods: In 7.3, DC power quality measurement methods is introduced based on AC methodologies. And some additional DC power quality indices are recommended to assess the DC system. DC electric power and power quality measurement methods are introduced in 7.4, defining the electric value integration time and frequency ranges. Typical electric power and power quality computation methods are modified in Annex D.
• g) Added an annex on MVDC system: A use case of a typical MV&LVDC distribution system is added in Annex F, to support developments of TS of 8A and 8B on DC microgrids.
• h) Added an annex on CurrentOS voltage level: The voltage level applied in CurrentOS is introduced in Annex L to give more information on the LVDC voltage level recommendation.