The growing demand, popularity and hence markets in the field of renewable energy, such as solar power plants and battery storage systems evoke an ever stronger interest in high voltage and high current switching devices that meet the contemporary requirements in terms of safety, productivity – and efficiency.
With the HE-V series, Panasonic Industry has developed a compact, low-cost but highly efficient relay capable of switching a load of up to 1,000VDC 20A and 40A inrush current. Focusing on arc parameters to minimize size and cost, it features a very effective blow-out mechanism and an optimized extinction gap.
An epic leap in the structure of power supply systems
During the past two decades, energy supply systems have undergone substantial changes. More and more photovoltaic plants and battery storage systems have entered the market. Global solar power production and the demand to store this energy has increased exorbitantly – and is expected to further grow.
By far the highest power is generated in residential systems: In Europe alone, there are already millions of DC/AC inverters installed with a typical power between 2 and 10kW. They are directly connected to the grid as single-phase or as three-phase system. For the entire safety of the grid systems, these inverters must fulfill several international and local standards and regulations. To achieve full galvanic isolation, a DC main switch as a protective device is required in photovoltaic (PV) systems between the DC side of the inverter and the solar generator. Details are regulated in the IEC 60364-7-712:2017 standard to protect humans during installation and maintenance.
Most installations are in residential buildings, containing only one or two inverters, and manual switches are sufficient to fulfill basic safety requirements. With the recent trend in larger PV installations in solar plants or on top of roofs of industrial buildings, there are new regulations from the utilities to control power generation. Due to overcapacity on sunny days, power plants with more than 100KW need a shutdown function to reduce the production capacity. Therefore, a high number of inverters requires a remote-control function to be connected or disconnected from the grid.
With its HE-V relay series, Panasonic Industry offers a dedicated DC breaking relay designed for solar power installations and battery storage systems.
The primary purpose has been to develop a failsafe relay that is well suited for use in solar inverters, string boxes and battery storage systems as well as a general-purpose relay for a wide range of DC applications.
| Characteristic | Performance |
|---|---|
| Contact rating (resistive load) | 20A 1,000 VDC |
| Max. switching voltage | 1,000V DC |
| Max. switching current | 40A |
| Surge breakdown voltage | 12kV |
| Nominal operating power | 1.8W |
| Contact gap | >3.8 mm |
| Holding power | 210mW |
| Dimensions (L×W×H) | 41.0×50.0×39.4mm |
| Ambient temperature | -40 to +85o C |
For the sake of cost efficiency, it is based on a coil and the armature system of a conventional 2 Form A power relay with two double bridge contacts. The outer dimensions are 41.0 × 50.0 × 39.4mm (L×W×H).
The main difference between the body block of the standard relay and the HE-V relay is the reinforced contact area. Four separate arc chambers provide space for four permanent magnets. To reach the targets for energy saving, the coil bobbin and the magnetic circuit have been modified. This results in a coil holding voltage reduced to 33% of the nominal operating voltage, amounting to a permanent power of only 210mW. The armature block is slightly changed to fulfill the requirements for reinforced isolation up to 10kVDC. With this construction, a minimum clearance distance of more than 10mm between coil and contact and a surge breakdown voltage of 12kV is achieved.
The movable contacts are directly connected to the armature by insertion molding via the contact spring. The armature is connected to the coil block via the release spring.
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