GB/Z 20840.100-2023Instrument transformers - Part 100: Guidance for application of current transformers in power system protection (English PDF)

Foreword

This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part 1. Structure and Drafting Rules of Standardization Documents" Drafting.

This document is Part 100 of GB/T (Z) 20840 "Transformers". GB/T (Z)20840 has released the following parts.

---Part 1. General technical requirements;

---Part 2. Supplementary technical requirements for current transformers;

---Part 3. Supplementary technical requirements for electromagnetic voltage transformers;

---Part 4. Supplementary technical requirements for combined transformers;

---Part 5. Supplementary technical requirements for capacitive voltage transformers;

---Part 6. Supplementary general technical requirements for low power transformers;

---Part 7. Electronic voltage transformer;

---Part 8. Electronic current transformers;

---Part 9. Digital interface of transformer;

---Part 14. Supplementary technical requirements for DC current transformers;

---Part 15. Supplementary technical requirements for DC voltage transformers;

---Part 100. Application Guidelines for Current Transformers for Power System Protection;

---Part 102. Ferromagnetic resonance in substations with electromagnetic voltage transformers;

---Part 103. Application of transformers in power quality measurement.

This document is modified to adopt IEC TR61869-100:2017 "Transformers Part 100. Application of current transformers for power system protection" Guidelines". The document type was adjusted from IEC 's technical report to my country's national standardization guidance technical document.

Compared with IEC TR61869-100:2017, this document has made the following structural adjustments.

---Added Appendix A;

---Appendix B and Appendix C of this document correspond to Appendix A and Appendix B of IEC TR61869-100:2017.

The technical differences between this document and IEC TR61869-100:2017 and their reasons are as follows:

---Deleted the term "3.1.7 time" in IEC TR61869-100:2017 because the term is the same as its concept and duplicates the abbreviation;

---Adjust the content of "Note" to the main text (see 6.1.3.6) to improve the standard technical content;

---Deleted the last paragraph of 8.2 of IEC TR61869-100:2017, the first sentence of paragraph 2 in 11.2.1, and the last one of Table 12 The content on high impedance protection in the first row and the third row from the bottom is in line with the actual situation in our country;

---In "Torque is no longer required, a rated current of 1A is sufficient, even a value of 0.1A is now being discussed and already used in special fields "However, for the transient protection current transformer with large primary current (such as generator outlet with more than 10000A)", " For the inductor, a larger value can be selected for the secondary current, such as 5A (this is considered from the perspective of CT manufacturing), and the corresponding resistive load should also be in accordance with "convert with the square of the current" (see 11.2.2) to conform to the actual situation in my country;

---Change "ALF or Kssc greater than or equal to 20" to "ALF or Kssc greater than or equal to 10" (see 11.3.2) to comply with my country's The actual situation;

---Deleted the content about "high impedance differential protection" in 11.5.6 of IEC TR61869-100:2017 to conform to my country's actual situation Condition. The following editorial changes have been made to this document.

---The figure of the full text has been redrawn, and the curve description in the figure is directly marked in the figure. Change the inductor symbols in Figure 3, Figure 43 and Figure 59 Adjusted to commonly used domestic symbols;

---Adjust the three-phase terminal marks of IEC TR61869-100:2017 from "L1, L2, L3" to "A, B, C";

---Numbered the unnumbered formulas in IEC TR61869-100:2017 and adjusted the numbers of other formulas in the full text;

---Change "Note 1" in 3.1.3 to "Note";

---In Figure 14, vertical lines at the ordinate and ttfp,max are added;

---Adjust "delta=3°" in the text above Figure 24 to "deltaphi=3°";

---The "unit value" has been deleted from the ordinate in Figure 31;

--- Figure 38 adds t"al and its description, Figure 39 adds the description of t"al;

---The symbol "^Psisc" representing the AC magnetic flux component of the short-circuit current is added to the previous sentence of equation (30);

---The duplicate im has been deleted from the symbol description in Figure 43;

---Change "TPY20×5.5" in the first paragraph of 10.4 to "TPY level, Kssc=20, Ktd=5.5";

---In Table 10, the quotation "Standard Specification:" is added to the requirements for TPX, TPY and TPZ, and "Note" is adjusted to "Note 1", adding Added "Note 2. For the transient accuracy level, GB/T 20840.2 stipulates that the two specification methods cannot be mixed, otherwise the The requirements for current transformers may be excessive", and the footnotes and notes are interchanged;

---Added introductory words to 11.4.3.1.2, 11.5.2 and 11.5.3.2, and changed the content of "note" in 11.4.3.1.2;

---Added note 11.4.3.1.3;

---Changed the current flow direction in Figure 68;

---The format of Table 2 and Table 3 has been adjusted, and the expression form of some contents of Table 2 has been adjusted. Table 4, Table 5, Table 7, Table 8,

Introduction

The establishment of transformer standards is to establish a set of best evaluation criteria for transformers, from raw material selection, design, production to Provide guidance on the precautions required in production, inspection, selection, operation and maintenance. GB/T (Z) 20840 is intended to stipulate that it is applicable to transformers The principles and relevant rules for design, manufacturing, testing, operation and maintenance are planned to be composed of 14 parts.

---Part 1. General technical requirements. The purpose is to stipulate the requirements for the design, manufacture and production testing of various types of transformers. General technical requirements for compliance.

---Part 2. Supplementary technical requirements for current transformers. The purpose is to specify complementary technologies suitable for various types of current transformers Require.

---Part 3. Supplementary technical requirements for electromagnetic voltage transformers. The purpose is to stipulate that it is applicable to various types of electromagnetic voltage transformers Supplementary technical requirements.

---Part 4. Supplementary technical requirements for combined transformers. The purpose is to specify complementary technologies applicable to various types of combined transformers Require.

---Part 5. Supplementary technical requirements for capacitive voltage transformers. The purpose is to stipulate that it is applicable to various types of capacitive voltage transformers Supplementary technical requirements.

---Part 6. Supplementary general technical requirements for low power transformers. The purpose is to provide for the compensation of various types of low power transformers. Fulfill technical requirements.

---Part 7. Electronic voltage transformer. The purpose is to specify supplementary technical requirements applicable to various types of electronic voltage transformers.

---Part 8. Electronic current transformer. The purpose is to specify supplementary technical requirements applicable to various types of electronic current transformers.

---Part 9. Digital interface of transformer. The purpose is to specify the technical requirements for digital interfaces applicable to various types of electronic transformers.

---Part 10. Supplementary technical requirements for low-power passive current transformers. The purpose is to establish suitable for various types of low-power passive power Supplementary technical requirements for current transformers.

---Part 11. Supplementary technical requirements for low power passive voltage transformers. The purpose is to establish suitable for various types of low-power passive power Supplementary technical requirements for pressure transformers.

---Part 14. Supplementary technical requirements for DC current transformers. The purpose is to specify the compensation requirements applicable to various types of DC current transformers. Fulfill technical requirements.

---Part 15. Supplementary technical requirements for DC voltage transformers. The purpose is to specify the specifications applicable to various types of DC voltage and current transformers. Supplementary technical requirements.

---Part 100. Application Guidelines for Current Transformers for Power System Protection. The purpose is to use various current transformers in power systems Provides guidance on the application of protection.

---Part 102. Ferromagnetic resonance in substations with electromagnetic voltage transformers. The purpose is to control various types of electromagnetic Provide guidance on the generation mechanism and suppression of ferromagnetic resonance in voltage transformer substations.

---Part 103. Application of transformers in power quality measurement. The purpose is to analyze the application of various types of transformers in power quality measurement. Provide guidance on usage.

GB/T (Z) 20840 clarifies the technical specifications of various types of transformer products through 14 parts, and provides specific technical requirements, tests Projects, test procedures, test methods and operation guidance, etc. By establishing clear scope, terminology, technical requirements and test requirements for various products etc:, so that personnel engaged in related product design, production, testing and use can operate more clearly and accurately, thus providing a basis for design, It lays the foundation for manufacturing high-quality products, better promotes trade, exchanges and technical cooperation, and provides guarantee for the normal operation of my country's power grid.

Since the promulgation of GB 16847-1997 "Technical Requirements for Transient Characteristics of Current Transformers for Protection", the application of current transformers for transient protection has The scope of use continues to expand. Therefore, the theoretical background for designing according to power system requirements becomes increasingly complex. This document is for Supplement to the technical content of GB/T 20840.2, and at the same time, background information on transient protection characteristics and its historical version of GB/T 20840.2 The technical content in this book is compared and explained, which is helpful for users to further understand the technical content of GB/T 20840.2.

1 Scope

This document provides advanced information for understanding the definition and requirements of electromagnetic current transformers (CT) for the general user or expert. information to help protective relay manufacturers, current transformer manufacturers and project engineers understand how current transformers respond to simplified or standard Standardized short circuit current signal. Where necessary, some abstract concepts are also covered, and responsibilities in the current transformer design process are discussed. aspects of the problem.

This document applies to electromagnetic current transformers for protection that comply with the requirements of GB/T 20840.2.

2 Normative reference documents

The contents of the following documents constitute essential provisions of this document through normative references in the text. Among them, the dated quotations For undated referenced documents, only the version corresponding to that date applies to this document; for undated referenced documents, the latest version (including all amendments) applies to this document.

GB/T 15544.1-2023 Calculation of short-circuit current in three-phase AC systems Part 1. Current calculation (IEC 60909-0:2016, MOD)

Note: There is no technical difference between the quoted content of GB/T 15544.1-2023 and the quoted content of IEC 60909-0:2001.

GB/T 20840.1-2010 Transformers Part 1. General technical requirements (IEC 61869-1:2007, MOD)

Note: There is no technical difference between the quoted content of GB/T 20840.1-2010 and the quoted content of IEC 61869-1:2007.

GB/T 20840.2-2014 Transformers Part 2. Supplementary technical requirements for current transformers (IEC 61869-2:2012, MOD)

Note: There is no technical difference between the quoted content of GB/T 20840.2-2014 and the quoted content of IEC 61869-2:2012.

3 Terms, definitions and symbols