How Petronas Conducted Protection and Selectivity Studies for the RAPID Project Using ETAP Modeling

There are over 20 ETAP models from various EPCC contractors. A team led by my department was assigned to integrate all the models into one. We have to perform simulations of the complex as one integrated system. I can say that the integrated model reached up to 5000 buses if we look into the 275kV system.
By Mr. Rahman Waruah Matollah, Staff Engineer, Electrical Protection and Control, at PETRONAS

This presentation discusses the root cause of sympathetic relay operation during a line-to-ground simulation and the recommended solutions to mitigate it. Using ETAP's special features, engineering design firms and plant operators can understand the protection relay behavior during faults. A protection Coordination evaluation study for the RAPID complex was performed using "PD Sequence-of-Operation" to identify abnormal relay behavior. The power plant inside this vast complex is connected to the 275kV national grid system. Many engineering, procurement, construction, and commissioning companies (EPCC) working on the RAPID project use the rules suggested by Petronas.

Petronas (Petroliam Nasional Berhad) is a global energy company committed to producing and delivering energy and solutions needed to advance society responsibly and sustainably. As Malaysia’s national oil and gas company, Petronas safeguards and manages hydrocarbon resources. It aims to maximize value through an integrated business model to meet the energy needs of the nation and our customers across the globe.
Petronas is developing a Refinery and Petrochemical Integrated Development project (RAPID) and other associated facilities in Pengerang, Southern Johor, Malaysia, through a Pengerang Integrated Complex (PIC) project.

Location: Kuala Lumpur, Malaysia

Year: 2021

Providing complex earthing protection coordination study for EPC contractors working for the RAPID project

Challenges

  • Finding the right tool to make a virtual model of the RAPID electrical network. EPC contractors use the ETAP models in their designs. The facilities use many voltage levels: 400 V, 3,3 kV, 11 kV, and 275 kV. Malaysia operates 132 kV and 275 kV transmission systems.
  • Integrating all 20 EPPC models into one complex ETAP model. This model should enable the analysis of earthing solutions and protection methods.
  • Performing simulations on the complex, integrated distribution system with three substations for 275kV, 22 for 33kV, 55 for 11kV, and a lot of LV substations.
  • Providing the mitigation technique for sympathetic relay operation during a line-to-ground fault.
  • To answer a question of any potential risk of hazardous current flow, especially during line-to-ground faults. The 275 kV transformer is grounded at both the sending and receiving ends. Grounding a transformer at both ends triggers a question about circulating earthing currents.
  • Evaluating the EPC electrical design processes by finding recommendations with clear conclusions to use by every designer in the RAPID project.
  • The short-circuit contribution must be limited to half to resolve the demand of the national grid operators.

Which solutions did they choose?

Selected applications

They utilize ETAP to model and analyze the electrical topology of this vast project involving a refinery, petrochemical plant, and other associated facilities. The ETAP Digital Twin solution collects and processes enormous data and information about the electrical installation in RAPID.

A special ETAP software, Star - Sequence-of-Operation (PD Sequence-of-Operation), was used to check, evaluate, verify, and confirm the operation and selectivity of the protective devices for various fault types.

Why do they use ETAP?

Main Customer Benefits

  • The key success factor for this integrated study was the number of the right ETAP models from EPCC. Petronas took them from all EPCC consultants and verified them before integration.
  • They could use checked engineering data. Multiple engineers and various types of studies assessed the common working electrical data. Using the same model, they could run workflows for short circuits, transient stability, harmonic reliability, and more.
  • Engineers could perform simulations of the complex as one integrated system. The integrated model reached up to 5000 buses.
  • The system topology was simplified to the one main single-line diagram, enabling protection analysis. Both 275kV transformers at the sending end and receiving end were solidly grounded. 275 kV transformers have a permanently grounded neutral point (solid ground) to achieve lower dielectrics trying requirements.
  • Petronas team identified abnormal relay behavior thanks to use of the ETAP "PD Sequence-of-operation" function, to verify the protection coordination study done by over 20 EPC consultant. This function helped to evaluate the protection coordination proposed by EPC contractors. They found an issue with the sympathetic relay operation and all 275 kV healthy feeders. The protection relay on healthy feeders has an unnecessary pickup, and if the main protection fails to clear the fault, provoking a wider outage for the complex installation.
  • Thanks to ETAP Star PD Sequencer, they made the positive, negative, and zero sequence networks during line-to-ground faults. They could evaluate every sequence and make recommendations.
  • EPC consultants and designers should use new three recommendations: install double main differential protection, use bidirectional protection, and for 132 kV and 275 kV transmission systems only use solid grounding protection (such as differential, distance, and backup by overcurrent protection).

What do they think about ETAP?

Opinions

The ETAP model must be done correctly in the first place. Specific to the 275kV system, we simulated line-to-ground fault at one of the 275kV transformer feeders. From the observation, we found an issue with the sympathetic relay operation and all 275 kV healthy feeders. The protection relay on healthy feeders has an unnecessary pickup, and if the main protection (in this case, we refer to the differential protection) fails to clear the fault. There will be a wider outage for the complex.
By Mr. Rahman Waruah Matollah, Staff Engineer, Electrical Protection and Control, at PETRONAS

In conclusion, ETAP "PD Sequence-of-operation" is a special feature to identify the direction and magnitude of circulating earth current during a line-to-ground fault, especially for the circuits we've grounded at both ends. It will help engineering design firms and plant operators understand the protection relay behavior during faults. This relay behavior may not be detected using the conventional TCC method.
By Mr. Rahman Waruah Matollah, Staff Engineer, Electrical Protection and Control, at PETRONAS


Videos

Protection & Selectivity in Industrial Facilities

Protection & Selectivity in Industrial Facilities

PETRONAS RAPID project is the largest oil & gas refinery and petrochemical plant in Malaysia which is powered by a 1200MW utilities plant and connected to a 275kV Grid supply. The integrated ETAP model for the RAPID complex reached up to 5000 buses that consist of various distribution voltages from 400V up to 275kV. Protection Coordination evaluation study for the RAPID complex was performed using “PD Sequence-of-Operation” to identify abnormal relay behavior, which may not be observed in the conventional TCC curve. When simulating earth fault at 275kV system, there is sympathetic relay operation at all 275kV healthy feeders due to circulating earth fault current. The circulating earth fault current is more than 1pu, which will potentially cause a broader outage to the RAPID complex. Further analysis has been performed by the author and academician experts to ascertain the root cause of the circulating earth fault current. This presentation will discuss the root cause of sympathetic relay operation during 275kV earth fault simulations and the recommended solutions to mitigate the sympathetic operation. This will help engineering design firms and plant operators clearly understand the protection relay behavior during faults by utilizing ETAP special features.


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