Solar / Photovoltaic


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BENDER is a worldwide leader in providing ground fault protection equipment to the solar industry. Whether the array is grounded or ungrounded, BENDER offers a specially tuned product to protect array and inverters:

Ungrounded Arrays

NEC Article 690.35 requires ground fault protection on ungrounded DC arrays. The BENDER isoPV ground detector provides early indication of such faults, before leakage current may even be present. The isoPV is specially tuned to operate on photovoltaic systems and detect both AC and DC ground faults by monitoring the system's insulation resistance.

The isoPV's digital display shows the insulation resistance of the array in real-time. Alarm LEDs provide visual indication of an alarm state. Two voltage-free SPDT alarm contacts are provided in the event of an alarm.

Grounded Arrays - Solve the Blind Spot Issue with BlindSpot® Protection Products

Typical ground fault protection applications, such as the use of a fuse, in grounded solar arrays can encounter the "blind spot" issue - a ground fault on the already grounded conductor of a PV array does not drive sufficient current to trip the fuse. Additional faults can go undetected and cause unexpected behavior, leading to a high risk of fire. Bender's RCMA and RCMS series products detect low-level ground faults on grounded arrays by using a differential measurement method, thereby mitigating the blind spot issue. Advanced technology alerts technicians to conditions that may lead to fire on PV arrays. Bender's BlindSpot protection products include the RCMA420, RCMA423, and RCMS series ground fault relays, and more.

Grounded Arrays - At the Inverter

NEC 609.5 requires ground fault protection for inverters on grounded arrays. BENDER's RCMA series of ground fault monitors meet the requirements of today's photovoltaic systems by providing an advanced means of ground fault detection for arrays and inverters. The RCMA423 digital monitor detects both AC (up to 2000 Hz) and DC ground faults over a widely adjustable range. Utilizing an external current transformer, the RCMA423 monitors the inverter ground for any ground faults that may occur. A wide range of modular current transformers ensures that virtually all sizes of inverters may be monitored. A digital display shows the amount of ground fault current in real-time. Two sets of voltage-free SPDT alarm contacts are available in the event of a fault.

Grounded Arrays - At the Combiner Box

The RCMS460 and RCMS490 series monitors utilize up to twelve separate channels to monitor individual string groups at the combiner box level. A detailed digital display shows which string group contains the fault. The RCMS490 additionally features separate contact outputs for each string group in the event of an alarm. Remote communication capabilities provide a simple means of notifying personnel.