Development of Independent‐Type Optical CT

Abstract

SUMMARY Optical current transformers (CTs) have the advantages that they can be made much smaller and lighter than conventional electromagnetic induction transformers by their simple structure, and contribute to improvement of equipment reliability because of their excellent surge resistance performance. The authors consider optical CTs to be next‐generation transformers, and are conducting research and development of optical CTs aiming to apply them to measuring and protection in electric power systems. Specifically, we developed an independent optical CT utilizing basic data on optical CTs accumulated for large‐current characteristics, temperature characteristics, vibration resistance characteristics, and so on. In performance verification, type tests complying with IEC standards, such as short‐time current tests, insulation tests, accuracy tests, and so on, showed good results. This report describes the basic principles and configuration of optical CTs. After that, basic characteristics of optical CTs including the conditions and results of verification tests for dielectric breakdown characteristics of sensor fibers, large‐current characteristics, temperature characteristics, and vibration resistance characteristics are described. Finally, a development outline of the independent optical CT intended for application to all‐digital substations and its type tests results are described. © 2013 Wiley Periodicals, Inc. Electron Comm Jpn, 97(1): 28–36, 2014; Published online in Wiley Online Library (http://wileyonlinelibrary.com). DOI 10.1002/ecj.11487

Study on Method for Field Secondary Signal Simulation of Optical Current Transformer

“…The optical current transformer [1,2] is widely used in the power system, especially the HVDC project [3,4], and plays an important role on the security and stability of the power system. As a core measuring equipment of HVDC, the optical current transformer is used to measure current including DC line current, pole bus current, valve high-side current, high-side current and imbalance current between the capacitor of AC or DC filter [5] and provide accurate and reliable measurement data for DC control and protection system [6]. It could have significant impact on performance of the DC control and protection system [7].…”