THE National Grid Corporation of the Philippines’ (NGCP) call for better and proper power system planning across all three main members of the energy supply chain – generation, transmission and distribution – got a stronger backup.
This was following the system disturbance and widespread power outages in Panay Island from April 27 to 29 and the red alert status raised in Luzon on May 8.
NGCP explained that while there were grid incidents monitored in both the Panay outages and Luzon red alert, these incidents ought not to have caused the effects seen.
“In the case of Panay Island, NGCP’s protection systems, which were communicated and coordinated with its grid-connected customers from both the generation and distribution sides, functioned as intended,” NGCP said. “As we explained to Congress, only the consumers connected to the line that tripped should have been disengaged from the grid. It was unfortunate that a power plant disengaged from the transmission system unexpectedly.”
It added, “This response from the generating unit is both unexpected and undesirable. The resulting undervoltage and underfrequency were severe and unrecoverable, and were the direct cause of the tripping of other power plants connected to the system, and ultimately, the Panay sub-grid collapsed.”
In a letter to Iloilo City’s Mayor Jerry Treñas, NGCP president and chief executive officer Anthony L. Almeda said “what happened to Panay last April 27 to 29 was both unfortunate and unacceptable, and everything must be done to prevent this from happening again.”
The subsequent trippings that occurred on April 28 and 29 were a direct result of the avoidable events of April 27.
“As grid operator and from a transmission point of view, NGCP assures the City of Iloilo that we will exert all efforts and implement all necessary transmission solutions to prevent this from happening again. With respect to the other sectors comprising the energy supply chain, we ask that they do the same,” Almeda stressed.
He added that they are asking for the cooperation of all members of the energy sector in making available, in a timely manner, all respective records, settings, and protection systems to come up with lasting solutions and provide the people of Iloilo City with immediate and accurate information.
“We ask for your continued support in the pursuit of our mandate. We remain committed to addressing all energy industry concerns, insofar as transmission is concerned, and continue to pledge our cooperation and devotion to finding holistic and long-term solutions,” said Almeda.
As for the Luzon red alert, NGCP’s initial investigation on the sequence of events on May 8 showed the tripping of Bolo-Masinloc 230-kiloVolt (kV) Line 2. This line is N-1, or operates with a redundancy. The load carried by Line 2 when it tripped was automatically transferred to Line 1. Each of Lines 1 or 2 is more than capable to singularly carry the entire loading of the Bolo-Masinloc 230kV facility at any time.
Moving forward, NGCP emphasizes the need for the following:
* Keep all transmission and distribution lines free from any obstruction which may affect the reliable flow of power in the transmission system;
* Review generator settings to ensure coordination with the transmission system by submitting their respective unit protection and control settings. Generators should ensure and demonstrate that these settings will not cause the degradation of the power grid to which they are connected;
* Improve generation planning to avoid heavy loading of lines and ensure sufficient generation per island, with a well-balanced mix of fuels and technology;
* Effective use of emerging technologies such as energy storage systems, among others;
* Accelerate grid reinforcement projects with the support of national and local government and the public;
* Immediate, open, and transparent information exchange among all players in the energy supply chain; and
* Review of the Philippine Grid Code to cater to variable renewable energy sources.
The NGCP further commits to complete several large transmission projects within the next few months to help strengthen the transmission system and better support the power system.
“We continue to advocate for a holistic approach to power planning. Development in all sectors involved in the power industry must be coordinated, with due attention given to each. We support the Department of Energy in all its efforts, and we are confident of its continued support to all sectors,” NGCP said.
It also assures the public and its stakeholders that it is exerting all efforts to implement all necessary solutions to prevent any similar grid incident./PN
