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Transformer protection relay – RET670/RET650 


Transformer protection relay – RET670/RET650 

S5T and manufacturer Hitachi Energy have provided RET670/RET650 in Vietnam market. The product meets the maximum requirements of safety and certainty, helps the equipment to operate stably, and optimizes operating performance.


Table of Content

Transformers are the most important equipment in substations, helping to raise the power transmission voltage from the generators to the power system and reduce the voltage to supply the loads. Understanding that, S5T and manufacturer Hitachi Energy have provided RET670/RET650 in Vietnam market. The product meets the maximum requirements of safety and certainty, helps the equipment operate stably and optimizes operating performance.


Hitachi Energy’s protective relay products

Some advantages of RET670/RET650 . transformer protection relay

With many years of experience and millions of IEDs operating on the global power system, Hitachi Energy provides protection solutions for RET670/ RET650 transformers. The product can meet all protection requirements for two-winding transformers, three-winding transformers, autotransformers. Hitachi Energy’s Relay is trusted by customers because of its modern, intelligent, fast-acting solution and stable and reliable operation.
  • Comprehensive protection, control and monitoring for two-winding transformers, three-winding transformers, GSU booster transformers, 87GT transformer block, special transformers used for high-speed railway industry, electric resistance.
  • Operating with a wide frequency range suitable for protection of transformers operating on power grids with variable frequency fluctuations.
  • The 87REF limited earth fault differential protection function works quickly with high sensitivity, making the relay protectable in the event of an internal fault near the neutral point of the high-voltage winding.
  • Relay also has the ability to control the change of voltage steps automatically to help adjust the voltage easily. Capable of controlling circuit breakers, isolators and monitoring circuit breakers, transformer loss of insulation monitoring.
  • Easy integration with traditional substation protection systems and digital substations.
  • The maximum number of Analog input channels up to 24AI (RET670) and 12AI (RET650) allows protection of all types of transformers from simple modal diagrams to complex modal diagrams.
  • Analog input channels are used to configure flexibly, allowing users to customize their use according to CT/VT channels.
  • The hardware of the RET670/REG670/REC670… in the Redlion 670 product line uses the same platform so that users can adjust the hardware of the relay lines together. This helps customers to optimize repair and replacement costs, and operate flexibly and simply.
  • The small ½ 19inch RET650 with integrated 12AI is suitable for protecting small power transformers with simple scheme schemes, saving upgrade costs.
  • The RET670 is available in ½, ¾, 1/1 19 inch sizes and integrates up to 24 Analog inputs suitable for protection of large power transformers with complex modal schemes.
  • The trip time of the 87T differential protection is only about <20ms, which is one of the fastest differential protection relays available today.
  • PCM600 configuration software is compatible with Windows 10, 11 operating systems.
  • Diverse, high-speed connections according to current standards of the electricity industry:
+ IEC 61850-8-1.
+ IEC 62439-3 (PRP).
+ IEC 62439-3 (HSR).
+ IEEE 802.1D (RSTP).
+ IEC/UCA 61850-9-2LE support 8 MUs.
+  IEEE 1344.
+ IEC/IEEE 60255.118 (C37.118).
+ IEC 60870-5-103, DNP 3.0, SPA, LON.

Typical operating modes of Hitachi transformer protection RET670/RET650 relay

Sơ đồ bảo vệ máy biến áp 2 cuộn dây của RET670-24 Analog input

Sơ đồ bảo vệ máy biến áp 2 cuộn dây của RET670-24 Analog input
Sơ đồ bảo vệ máy biến áp 3 cuộn dây của RET670-24 Analog input
Sơ đồ bảo vệ máy biến áp 3 cuộn dây của RET670-24 Analog input
Sơ đồ bảo vệ máy biến áp 2 cuộn dây của RET65012-Analog input
2 winding transformer protection diagram of RET65012 – Analog input
Sơ đồ bảo vệ máy biến áp 3 cuộn dây của RET650 -12 Analog input
3 winding transformer protection diagram of RET650 -12 Analog input

Services S5T provides

Currently, S5T Technology and Solution JSC is an authorized dealer of Hitachi Energy, responsible for distributing protective relays for generators, transformers, busbars and lines. Details of services that S5T provides when installing relay RET670/RET650 include:
  • Deployment and installation of new relay systems to protect generators, transformers, substations and lines.
  • Design consulting service, upgrade, renovate, replace the old relay system with the new relay system of Hitachi Energy.
  • Sales services and technical service solutions related to Hitachi Energy’s protection relay systems.
  • Training service, breakdown analysis, ready to support customers when encountering defects and problems related to the protection relay system.

Procedure to upgrade the relay system RET670/RET650 to protect the generator

Installing Hitachi Energy’s transformer protection relay system, S5T deploys according to the following process:
Step 1: Survey the existing relay system.
Step 2: Make a technical plan and design a diagram of SLD protection methods, make a BOM list of equipment used for replacement or upgrade.
Step 3: Deploy bid.
Step 4: Design the diagram of protection method and detailed design drawing, coordinate with dispatching level Ax to calculate and adjust.
Step 5: Deploy on-site installation, configuration, experiment, test run.
Step 6: Deploy training manuals and technology transfer.
Step 7: Care and support for customers after the system is put into operation.

Why should you choose to install the RET670/RET650 relay system to protect the S5T transformer?

S5T Vietnam Technology and Solution Joint Stock Company is currently the No. 1 reputable supplier of Hitachi Energy relay products. S5T owns a team of highly qualified staff who are capable of designing, upgrading and improving. create relay systems, and provide technical consulting services and support customers to handle defects, analyze problems.
  • Our technical team has experience in implementing and installing Hitachi Energy’s protection relay system, having participated in many projects at large factories such as: upgrading distance protection relay REL670 – Song Ba Ha Hydropower Plant, upgrading relay system to protect unit H3 Tuyen Quang Hydropower Plant …
  • A team of well-trained technical experts, having training certificates from Hitachi Energy, is autonomous in construction implementation, so the price is more competitive than other units.
  • We are ready to support customers 24/7 by online/offline forms, so make sure to answer questions quickly and promptly when needed.
For detailed information about products and services  provided when installing RET670/RET650, please send information to the mailbox for advice, or you can also contact us at the following address:
  • Address: S5T Vietnam Technology and Solution Joint Stock Company.
  • Lot B15, Duong Noi Resettlement Area, Duong Noi, Ha Dong, Hanoi.
  • Tel: 0243 540 1858 – Fax: 0243 540 1859
  • Email:
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Customers and partners need more advice about our products and services, please contact Hotline 0243 540 1858 or leave information for a free consultation.


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