Market: Energy Plant

Bestact products with built-in Bestact contacts meet the high demanding specifications from the energy plant market, such as substations, for stable operation in high and rare frequency use and operating speeds in a few milliseconds.
From 1981 to the present, these long-selling products have been used in a wide variety of equipment, from control devices in plants to devices mounted on utility poles in the city.

① Digital Protection Relay Devices

Bestact relays are used in digital protective relay devices that disconnect faulty sections from the grid at power generation and substations.
It quickly detects faulty sections of power transmission lines and other power facilities caused by disasters, etc., and outputs commands to switch the system.


Since power equipment failures lead to power outages, it is necessary to minimize the time of power outages by quickly disconnecting the faulty section.

This is why Bestact relays, which operate in less than 5 milliseconds and have a long life, are used to achieve instantaneous command transmission.

Adopted Products

② Disconnect switchgear open/close confirmation device

Bestact magnetic proximity switches are used to check the on/off status of disconnects and grounding devices.
It serves as a safety confirmation device to protect workers during equipment inspections.


Since it is necessary to check the condition of disconnectors when inspecting power facilities, the PSMS series Bestact proximity switches, which are non-contact and resistant to rare and frequent operation, were adopted.

The PSMS series proximity switches have a long service life and are resistant to contact failures, making them ideal for long-term, maintenance-free use.

 Adopted Products

③ Protective Relay for Power Distribution Monitoring and Control Systems

It is used as a return relay in the child station of a distribution line remote monitoring and control system that detects equipment malfunctions.
The child station is installed on a utility pole, and judges the faulty section by returning an open/close signal by remote control.


The stable supply of electric power requires monitoring the status of distribution lines, and in the event of a breakdown, the status of each sub-station must be instantly confirmed.

For this reason, the RI/RZDR series of Bestact board-type relays, which operate reliably even in infrequent use with an operating speed of 5 ms or less, are used to enable instantaneous status confirmation.

 Adopted Products