This article introduces relay roles and product information focusing on power storage systems.
What is a power storage system?
A power storage system repeatedly recharges high capacity storage batteries to store electricity and supply it to household electric devices. Relays used for the DC side (for switching direct current loads) of a power storage system are required to have high capacity DC cutoff capabilities and high reliability since they are used as safety cutoff relays in the event of defects and failures of the batteries and power storage system. In addition, relays used for the AC side (for switching alternating current loads) of a power storage system are required to provide high capacity AC cutoff capabilities and high reliability since they are used as safety cutoff relays for power grids to prevent abnormality in consumer side circuits from impacting commercial power supply circuits. Next, let's check these applications in more detail.
Relay roles and product information
(1) AC side safety cutoff
Relays are used to safely shut down power grids. When there are anomalies with the current converted by the inverter block of a power storage system, the current must be cut so that it doesn't impact the electric power on the commercial side (inverter block and storage batteries). High capacity relays are useful as safety measures for protecting electric power systems.
Recommended high capacity AC relays
| HE-N | HE PV | HE-S | LF-G |
 |
 |
 |
 |
（HE-N : 1a 120A 480V AC）
（HE PV : 1a 35A-90A 277V AC）
（HE-S : 2a/2a1b 35A 277V AC）
（LF-G : 1a 22A-33A 250V AC）
* Click the photograph of each product series to visit the website containing the corresponding detailed information.
▼ CAD/Catalog download
- Click here to download the HE-N relay data
- Click here to download the PV type HE relay data
- Click here to download the HE-S relay data
- Click here to download the LF-G relay data
(2) DC side safety cutoff
High capacity relays are key safety measures when there are defects and failures related to the storage battery block and the system side (inverter block) of a power storage system.
Recommended high capacity DC relays
<EP relays>
（1a 80A-300A 1,000V DC ※） ※ 1,000 V DC is the Max. switching voltage. The rating is 400 V DC.
＊ Click the photograph of each product series to visit the website containing the corresponding detailed information.
- Click here to download the CAD and catalog data
(3) For preventing inrush current to capacitors when a power storage system is charged (pre-charge circuit)
The power storage system turns ON the relay for preventing inrush current when it starts up and then turns ON the main relay after the storage batteries (capacitors) are charged. High capacity relays are suitable for applications handling high capacity and high current devices. Accordingly, relays also effectively work as protection against inrush current generated when storage batteries (capacitors) are charged.
Recommended relays for pre-charge circuits
<EP relays>
（EP : 1a 10A-20A 1,000V DC ※1） ※1 1,000 V DC is the Max. switching voltage. The rating is 400 V DC.
<HE-V relays>
（HE-V : 2a 20A 1,000V DC ※2） ※2 1,000 V DC is the Max. switching voltage when each 1 Form A contact is connected in series. The rating is 800V DC.
＊ Click the photograph of each product series to visit the website containing the corresponding detailed information.
▼ CAD/Catalog download
- Click here to download the EP relay data
- Click here to download the HE-V relay data
Was it clear that high capacity relays are useful as safety cutoff relays for the AC and DC sides of a power storage system as well as safety measures for preventing inrush current to the storage batteries?
* From a safety perspective, the use of our relay requires manufactures to confirm specifications and conduct evaluation test. Please understand that safety considerations prevent us from receiving inquiries from or dealing with private customers.
