GOST 21023-75 PDF

Full title and description

GOST 21023-75 — Power transformers. Methods of measuring partial discharge characteristics during power‑frequency voltage testing. The standard specifies methods, measurement arrangements and requirements for recording and evaluating partial discharge (PD) characteristics when testing oil‑immersed power transformers at industrial (50/60 Hz) frequency.

Abstract

This Soviet-era standard defines procedures to measure and quantify partial discharges in power transformer insulation under power‑frequency test voltages. It covers measurement circuits, calibration (grading) of the measuring system, noise‑reduction measures, test voltage waveforms and durations, required PD parameters (for example apparent charge and maximum apparent charge during the test), and reporting of results. The methods are intended to establish whether PD activity in the tested transformer exceeds values permitted by the transformer technical specification or normative documents.

General information

• Status: National standard of the former USSR; reissued with amendments and maintained in national collections (historical/technical standard used for transformer PD testing methodology).
• Publication date: Approved 25 June 1975; introduced (date of application) 1 January 1977; reissued (reprint) December 1996 with Amendments Nos. 1–4 noted in later bulletins.
• Publisher: Gosudarstvennyy komitet SSSR po standartam (Gosstandart of the USSR) — State Committee for Standards of the USSR (original publisher).
• ICS / categories: 29.180 — Transformers. Reactors (Electrical engineering: transformers, related test methods).
• Edition / version: Original designation ГОСТ 21023-75 (1975) with subsequently published amendments (Amend. 1–4) and a reprint (1996); often cited as the 1975 edition with changes incorporated in bulletins and reprints.
• Number of pages: Approximately 12 pages (standard text with figures and tables). This field is an approximate value when exact scanned/printed sheet count is not available in the consulted catalogue records.

Scope

Applies to oil‑filled power transformers (including autotransformers) of 220 kV class and above and establishes methods to measure PD characteristics during power‑frequency dielectric tests. The standard does not cover transformers already in service (it is intended for type, routine and acceptance testing in factory and test‑station environments). Specific measurement arrangements, limits for connecting capacitors, and calibration procedures are given so PD in the transformer insulation can be reliably detected and quantified.

Key topics and requirements

• Measurement circuits and recommended connections for coupling capacitors and measuring elements (use of measuring tap / built‑in measuring electrode on HV bushings or separate coupling capacitor).
• Grading (calibration) of the PD measuring installation before and after tests and requirements for calibration capacitors and coefficients.
• Definition and determination of apparent charge of discharges, maximum apparent charge during the test interval, and required statistical/peak measurements.
• Procedures for reduction of interference (corona screens, filtering, grounding and screening arrangements) to ensure measured signals are attributable to internal PD and not external noise.
• Test voltage waveforms, ramping procedures and durations for one‑minute and long‑duration test voltages, and measurement timing (typical intervals and number of measurements during long tests).
• Requirements on acceptable PD level of the coupling capacitor relative to the transformer under test and limits on coupling capacitor capacitance for reliable measurement.

Typical use and users

Used by transformer design and test engineers, factory test laboratories, independent test houses, quality and acceptance inspectors, and research groups working on dielectric diagnostics. Typical applications include type tests, routine and acceptance (factory) tests of new oil‑immersed power transformers and autotransformers at or above the voltage class stated in the scope.

Related standards

Related and referenced normative documents include contemporaneous GOSTs for transformer testing and measuring equipment (for example standards covering test voltage generation and voltage dividers, bushings and insulation tests). The methods in GOST 21023-75 are aligned in methodology with international practice for PD measurement (for example IEC/EN documents addressing PD measurement techniques such as IEC 60270 and later successor documents). National adoptions and later national standards (for example some regional standards and the Ukrainian DSTU implementation history) have referenced or replaced this GOST in national practice.

Keywords

power transformer; partial discharge; PD measurement; coupling capacitor; calibration; test voltage; power‑frequency testing; transformer testing; dielectric diagnostics; oil‑immersed transformer.

FAQ

Q: What is this standard?

A: GOST 21023-75 is a Soviet national standard that specifies methods for measuring partial discharge characteristics of power (oil‑immersed) transformers during tests at industrial (power‑line) frequency. It provides measurement arrangements, calibration and reporting rules intended for factory and acceptance testing contexts.

Q: What does it cover?

A: It covers measurement circuits (including use of coupling capacitors or measuring electrodes), grading (calibration) procedures of the measuring installation, requirements to limit external interference, definitions and measurement of PD parameters (apparent charge, maximum apparent charge, etc.), and the test voltage waveforms and durations used during PD testing.

Q: Who typically uses it?

A: Transformer manufacturers, test laboratories, quality/acceptance engineers, and researchers involved in dielectric and insulation tests for high‑voltage power transformers use the standard as a methodological reference for PD measurements during type, routine and acceptance tests.

Q: Is it current or superseded?

A: The document is the 1975 GOST edition (introduced in 1977) and has been reissued and amended in later bulletins (amendments Nos. 1–4 and a 1996 reprint). In many jurisdictions and modern test laboratories international standards (for example IEC documents on PD measurement such as IEC 60270 and later related guidance) are used alongside or instead of older national GOST texts. National adoption and replacement have occurred in some countries (for example Ukraine replaced the GOST by a national DSTU standard referencing EN/IEC practice). Users should check the current national standards registry or national standards body for the operative test standard in their country or for any superseding documents before relying on a single historical text.

Q: Is it part of a series?

A: It belongs to the corpus of transformer testing standards (GOST series and related industry standards) that together cover mechanical, electromagnetic, thermal and dielectric test methods for power transformers. It is cited alongside other GOSTs that specify voltage generation, bushing and insulation test requirements and is part of the broader normative framework for transformer testing.

Q: What are the key keywords?

A: Partial discharge, PD measurement, coupling capacitor, apparent charge, power‑frequency tests, oil‑immersed power transformer, calibration (grading), interference reduction, transformer acceptance testing.