NOJA Power OSM series ACRs bring reliable power supplies to isolated Philippine islands

Electrical switchgear engineers NOJA Power today announces that its Quezon City, Philippines-based distributor, Power Equipment & Supplies Inc. (PESIN), is supplying OSM15 Automatic Circuit Reclosers (ACRs or “auto reclosers”) to National Power Corporation (NAPOCOR), a major Philippine utility. The ACRs are being used to connect and protect diesel-powered electricity generation for remote communities in the 7100-island archipelago.

NOJA Power has partnered with PESIN since 2004 and together the companies have been cooperating with NAPOCOR for the last two years. The latest ACR installations are for NAPOCOR’s Small Power Utilities Group (SPUG) and are part of standalone diesel-powered generating sets used on various islands to supply electrical power to remote communities. The diesel generation sets are operated for approximately 16 hours a day and produce 480 V which is stepped-up to 13.2 kV by transformers for distribution. Circuit protection and connection to the islands’ grids is made via single or multiple NOJA Power OSM15 ACRs.

Previously the diesel generator sets employed a circuit breaker between the generator and transformer and simple fuses to connect the 13.2 kV supply to the grid. This arrangement proved unreliable because on occasion the circuit breakers failed to trip after fuse operation causing damage to the generator sets. In addition, the blown fuses had to be manually replaced before power could be restored. Now, in the event of a fault, the OSM15 ACR performs a set number of reclose operations before locking out and sending a trip signal to the circuit breaker to guarantee the device’s operation. In addition, the ACR sends a throttle-back signal to the diesel generators to trigger a no-load idling condition. Upon rectification of the fault the ACR can be quickly closed to restore power.

In March 2016, NAPOCOR commenced installation and commissioning of the OSM15 ACRs with the units improving system reliability and eliminating diesel generator damage in the event of faults.

In the medium term NAPOCOR intends to take advantage of the OSM15 ACR’s remote communication capabilities. The OSM15 ACR’s RC control and communications cubicle includes ports for the connection of cellular (GSM or 4G) modems. Where a small island diesel generator installation is within 20 km of a larger island with a cellular network, an OSM15 ACR with a cellular modem will be used to send information via the cellular network to remote NAPOCOR control centres. The OSM15 ACR supports DNP3, 2179, IEC61850, IEC60870-5-101 and 104 communications protocols.

“Although much of NOJA Power’s business comes from demand for distribution automation equipment for major utilities’ smart grids, the flexibility of the company’s auto reclosers allows them to be used for even small distribution tasks,” says Neil O’Sullivan, NOJA Power’s Group Managing Director. “But while these diesel generator sets are small in terms of capacity, they are vital to these remote island communities who previously had to put up with intermittent service. By installing the OSM15 ACRs, NAPOCOR has dramatically increased the reliability and safety of supply to these communities. Further, the utility has an eye on the future with plans to leverage the auto reclosers’ built-in communication capabilities for remote control and system reporting."

“The combination of highly-reliable NOJA Power equipment and PESIN’s well-earned reputation for customer service was key to winning this contract,” adds O’Sullivan.

The Philippines has a population of 100 million spread across 7,100 islands. Such fragmentation makes it difficult to build a robust transmission and distribution system and in the remote islands, connection to the main power grid is often unviable because of the high generation costs and the low incomes of the end users. NAPOCOR’s SPUG has implemented a program to supply power to these off-grid areas. Where the group has installed equipment, the challenges in supplying power often mean that at best, electricity is available for 12 hours a day which can drop to 4 hours per day in instances of inclement weather. By protecting SPUG’s diesel-powered generating sets with NOJA Power’s ACRs, reliability of supply is increased and, when a fault does occur, power is quickly restored compared to replacing fuses. In the longer term SPUG intends to replace or supplement the diesel generators with solar, wind or hydroelectric energy sources. NOJA Power’s ACRs are ideally suited to renewable energy connection and protection.

The OSM15 ACR represents the most up-to-date distribution automation equipment available. The ACR has a rated maximum voltage of 15.5 kV, a rated continuous current of 800 A and a fault break capacity 16 kA. The ACR provides a comprehensive suite of protection and automation features, voltage measurement on all six bushings, current measurement on all three phases, bidirectional protection and extensive power quality and data logging capability. In addition, the OSM15 ACR benefits from the use of vacuum interrupters and solid dielectric insulation instead of the environmentally unfriendly oil or sulphur hexafluoride (SF6) gas used in older switches. The OSM series has been fully type-tested by independent laboratory KEMA in the Netherlands to ensure long life and reliability under the harshest environmental conditions.