How a BESS Facility Cut Isolation Switch Downtime by 60% with Soutya

2026-09-02 0 Leave me a message

A 220 MW battery energy storage system (BESS) facility in Southeast Asia faced a recurring problem: every routine inspection of its DC isolator switches forced a full shutdown of a battery cluster. Each window cost hours of lost revenue and created scheduling conflicts with the grid operator. By replacing 36 conventional load-break switches with the Soutya DC Drawout-Type Isolator Switch, the facility cut maintenance downtime on each isolation point by 60%, reduced annual operations costs by $25,000, and eliminated arc-related incidents for two consecutive quarters.

Customer Background

The facility is a grid-scale BESS plant supplying frequency regulation and peak-shaving capacity to a regional utility. Its DC switchgear room contains multiple battery racks feeding power conversion systems through 1,000 V DC busbars. The plant operates 24/7, and the utility contract allows only four maintenance windows per year, each capped at six hours.

The plant’s electrical engineering team manages over 200 isolator switches across four battery clusters. Before the upgrade, the maintenance procedure for a single switch required disconnecting the string, racking out an entire withdrawable chassis, and physically handling heavy copper busbars. The process was labor-intensive and prone to misalignment when reinserting the chassis.

Challenges and Pain Points

During the plant’s first year of operation, every quarterly inspection exposed the same limitations:

Isolating a single battery string required a full cluster shutdown because the existing fixed-mount switches could not be drawn out without separating the busbar.
A single maintenance event took 12 to 14 hours, exceeding the utility’s six-hour window.
The lack of visual indication on the switch made it difficult to confirm whether contacts were fully disengaged, increasing inspection time.
When maintenance crews attempted to speed up the process, they sometimes forced the chassis back into position, causing contact misalignment that led to localized heating and one minor arc event.

These issues translated into operational risk. The plant lost roughly $38,000 in avoided penalties and missed market opportunities during the first three scheduled inspections. In addition, the plant’s safety documentation flagged arc-flash exposure as a high-priority risk, because existing switches had no clear break indication.

Why Choose the Soutya DC Drawout-Type Isolator Switch?

The engineering team evaluated three options: a traditional fixed-mount DC isolator switch with interlocked covers, a motorized load-break switch, and a drawout-type isolator switch with visible contact gaps. The first option did not solve the shutdown problem. The second option introduced auxiliary supply requirements and a higher failure point.

The Soutya DC Drawout-Type Isolator Switch was selected for a different reason: it allows the switching element to be drawn out while the busbar remains energized and secured behind an internal shutter. This design eliminates the need to shut down the entire battery cluster. Its arc-extinguishing contacts are designed for low-voltage DC circuits up to 1,000 V, and the switch provides a clear, mechanically interlocked indication of contact position.

The plant manager also noted that Soutya’s product line follows the performance expectations outlined in IEC 60947-1 and GB/T 14048.1-2019, giving the engineering team confidence in the device’s electrical endurance and thermal behavior under repeated operations.

Implementation and Application Process

The replacement project took eight weeks from initial engineering review to full deployment.

Step 1: A thorough switching study mapped every isolation point and identified the optimal locations for drawout installation.
Step 2: A single battery string was retrofitted first during a scheduled outage. The team documented the new procedure and measured cycle times.
Step 3: Electrical diagrams and maintenance procedures were updated after the pilot string was verified through 30 full drawout cycles.
Step 4: The remaining modules were installed over the following weeks, using the same mounting dimensions as the original switchboard. No additional ventilation upgrades were required.

A typical challenge during implementation was aligning the drawout mechanism with existing cable compartments in one older section of the switchgear room. The Soutya unit’s guide rails were adjustable, which allowed the integration team to recalibrate the alignment within half a day. One older switchboard required a small busbar spacer, but no major redesign.

Quantified Results

After the first full quarter of operation, the facility recorded the following outcomes:

Average switch maintenance time dropped from 12.5 hours per point to 4.8 hours, a 62% reduction.
Annual operations and maintenance labor expenses decreased by $25,000, including the elimination of two emergency callouts.
Zero arc-flash incidents or contact-related failures were recorded during 150+ drawout operations.
The plant regained one additional full maintenance window per year because all battery clusters could now stay online during single-string isolation.

The improved confirmation of contact position also reduced human error. In the previous system, there was no clear way to check that the switch was fully open. Now, an integrated position indicator gives service technicians an immediate visual confirm before they open any bay door.

Client Testimonial

“The Soutya DC drawout switch solved the problem we struggled with for over a year,” said the facility’s electrical maintenance supervisor. “Our technicians can now isolate a single string safely and check the visible contact gap before starting work. The time savings were immediate, and the switch feels more robust.”

Lessons and Recommendations

Facilities operating DC switchgear can draw several lessons from this project:

Evaluate the full lifecycle cost of an isolator switch, not the upfront price. A switch design that allows safe, quick drawout can pay for itself in avoided downtime within two years.
Look for products with visible contact indication and mechanical interlocks. These features eliminate the guesswork that leads to arc-flash exposure.
Conduct a pilot installation on a single feeder before rolling out to the entire facility. That approach reduces risk and helps build internal familiarity with the new procedure.

If the project began again, the engineering team says they would install the drawout-type isolator switches from the very start of the plant’s construction, than retrofitting them after the first year. The extra design margin and simpler terminal arrangement would have made the original commissioning faster and improved the facility’s readiness for future capacity expansions.