New current transformer for bus differential protection

When the Optical Current Transformer (OCT) with different sampling frequencies is applied to differential protection, the output data of OCT of each branch of the differential protection are required to be converted to a uniform sampling frequency. The filtering algorithm is inevitably applied in the progress of frequency conversion. In the essay, a new Zero Phase Maxflat filtering algorithm, the prototype of which is IIR digital filter, achieving zero phase maxflat pass band amplitude characteristics and zero-phase filtering. The algorithm is with high accuracy and achieves a rapid filter with lower order along with the shorter filter time and fast protection action. In the end, simulation is used to verify the feasibility and effectiveness of the algorithm.

Download Full-text

Histogram-Based Method to Avoid Maloperation of Transformer Differential Protection Due to Current-Transformer Saturation Under External Faults

IEEE Transactions on Power Delivery ◽

10.1109/tpwrd.2017.2712806 ◽

2018 ◽

Vol 33 (2) ◽

pp. 610-619 ◽

Cited By ~ 8

Author(s):

Tao Zheng ◽

Ting Huang ◽

Yulong Ma ◽

Zihang Zhang ◽

Lianguang Liu

Keyword(s):

Current Transformer ◽

Differential Protection ◽

Transformer Differential Protection ◽

External Faults

Download Full-text

The Analysis and Discussion of the Actual Case about the Differential Protection Malfunction Caused by the Transient Exciting Current of Large-Scale High-Voltage Main Transformer at the Time of Switching

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.694-697.785 ◽

2013 ◽

Vol 694-697 ◽

pp. 785-789

Author(s):

Yang Gao ◽

Guo Yan Liang

Keyword(s):

High Voltage ◽

Large Scale ◽

Current Transformer ◽

Differential Protection ◽

Instrument Function ◽

Actual Case ◽

Test Analysis ◽

Use Of Data ◽

Exciting Current ◽

Transformer Differential Protection

In this paper, based on the choice of voltage level 500kV for large transformer differential protection of maloperation accident actually as an example, discusses how to improve the reliability and the transformer differential protection with the relationship between pressure test. Analysis found that in order to avoid the excitation transient exciting current transformer differential protection sparked the misoperation, on-site technical personnel in the differential protection setting calculation process, make use of data in conformity with the relevant parameters, rules and standards, familiar with differential protection, also need to understand the characteristics of transformer excitation transient exciting current high-voltage tests, the influence of characteristic more should fully exert the modern PC wave record device, instrument function can improve the actual effect of transformer differential protection. This factory for transformer differential protection for setting, protection greatly improves the reliability. This experience is worth popularizing.

Download Full-text