Smart Interlock System Prevents Human Error in Substations

Complete solution for safe switching operations

Mountain View, California - Unitech Smart Interlock System is a computer-based interlocking system designed to minimize human switching errors in substations.

Smart Interlock System provides a real-time simulation system that accurately models the connectivity of the substation and verifies logic of switching sequences. Through simulation, each switching step is proven safe before switching takes place.

With the unified standardized lock cylinder, the operator only needs to carry the Smart key to open all locks. By the use of RFID verification, the Smart Key enforces that the switching personnel operates the equipment in the correct sequence.


Smart Interlock System (SIS) is a computer based system designed to prevent human errors within substations. SIS consists of three main components, SIS host software, Smart Key and locking devices.

SIS host software has a user friendly graphical interface that simulates an operating order based on real-time equipment status and switching logic defined by customers. Through communication with RTU, SIS software displays a one-line diagram that reflects the real-time status of substation equipment. SIS host software uses AMEO programming language to express switching rule and interlocking logic for primary equipment within the substation. Using the real-time simulation system, each step of the operating order is verified, thus ensures the correctness of the operating order.

After simulation, the electronic operating order will be generated and transmitted to the Smart Key. With a unified lock cylinder, Smart Key is the single device that an operator needs for any substation operation. By following the operating order displayed on the Smart Key screen, the operator can easily locate designated devices. Smart Key ensures operations are carried out in the correct sequence and on the correct device by RFID verification.

SIS provides hundreds of locking devices and accessories to fulfill different interlocking requirements. All possible lock points are covered by the most suitable locking methodology ranging from regular padlock to control circuit lock. Each locking device can be uniquely identified by an embedded RFID chip. Unitech was established in 1991 and has over 24,500 deployments in substations, switch yards and power plants worldwide. Additional information can be found at

About Unitech:

Unitech is an industry leader in switching safety solutions. Established in 1991, Unitech products have been deployed in more than 24,500 power plants and substations worldwide to prevent power interruptions, equipment damage, and loss of human life. For more information, please contact Unitech by phone at (650) 965 1228, by email at or visit our website at


Press/Technical contact:

Danning Jiang

650 965 1228

General public:

Sean McGuinness


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