Supporting Grid Resilience in Macau: Condition Assessment for Transformers of CEM
Customer Story | 4 min read
Companhia de Electricidade de Macau (CEM) is the sole electricity provider in Macau, responsible for transmission, distribution, and sales of electricity across various voltage levels. To ensure grid stability and reliability in the region, CEM required a comprehensive condition assessment of their transformer fleet, which was executed by Hitachi Energy. This led to the implementation of proactive maintenance strategies, addressing outdated components and providing the necessary guidance to extend the operational life of their transformers.
Challenges
Renewing Macau's power grid: Navigating the complexities of transformer replacement
CEM operates an extensive transmission network that includes 27 primary substations and 8 high-voltage switching substations, with 1,078 kilometers of high-voltage cables. Additionally, they manage two power stations on Coloane Island, with a total generation capacity of 407.8 MW.
Recognizing transformers' critical role in maintaining the power grid's stability and reliability, CEM undertook a project to update their transformer fleet to meet current standards and environmental regulations. CEM's commitment to high power reliability necessitated a careful assessment of each transformer to evaluate its health status and determine the required upgrades. The goal was to extend the operational life of transformers while accommodating the annual growth rate of energy consumption, which was 9.1% in 2023, without compromising safety or reliability.
The primary challenge was that most transformers had been in service for over twenty years, making many external components outdated and no longer in production.
Project data
Customer: Companhia de Electricidade de Macau (CEM)
Location: Macau, China
Application: Transformer Service
Solutions: Transformers Assess and Secure
- Condition Assessment: 9 small power transformers (66 kV and 110 kV)
- Asset Performance Management (Lumada APM)
Solution
Hitachi Energy's comprehensive approach to transformer assessment
Hitachi Energy's general methodology for assessing a fleet of transformers, which is also applied in this project with CEM involving 9 Small Power Transformers (66kV and 110kV), involves using the Asset Performance Management (Lumada APM) software. This software is designed to be flexible, catering to various levels of detail as required by the end-user’s needs.
The process begins with a broad scan of many transformers using easily accessible data such as nameplate information, standard oil and dissolved gas data, load profiles, and the unit's history. This initial step aims to identify which units need further, more detailed analysis, excluding those operating normally.
Experts conduct a detailed Condition Assessment for transformers identified as high-risk during the initial screening. This involves advanced diagnostics, site inspections, and testing using tools like Dissolved Gas Analysis (DGA), Furans, Sweep Frequency Response Analysis (SFRA), Frequency Domain Spectroscopy (FDS), and Partial Discharge tests. These methods help evaluate the transformer's main properties and assess the risk of failure.
Only a limited number of units undergo this in-depth analysis, which includes thermal simulations, mechanical calculations, and electromagnetic field computations. An internal calibration by a global expert team categorizes transformers into "normal," "attention," and "abnormal" states, providing specific recommendations for each.
The goal is to identify weak points and make necessary improvements to ensure the transformers meet serviceability requirements using the latest design and simulation tools from Hitachi Energy. This thorough approach, tailored to the user's specific needs and constraints, ensures an efficient and effective fleet assessment.
Benefits
Driving asset performance management and sustainability in Macau's power sector
The collaboration between Hitachi Energy and CEM showcases condition assessment methodologies, which are not only a proven technical solution but also a forward-looking strategy aligned with the goals of reliability, sustainability, and resource efficiency.
In this way, condition assessment and transformer life extension become a cornerstone of a resilient and sustainable energy system.
Hitachi Energy will complete the transformers' assessment according to CEM’s customer’s power outage plan and allow a smooth energy supply during regular operations.
By focusing on predictive maintenance strategies, Hitachi Energy met CEM's needs with its expertise. Hitachi Energy's methodology for assessing transformer condition is setting a benchmark for future projects and reinforcing its experience as a trusted partner in the transformer lifecycle, minimizing unplanned outages and ensuring operational continuity.
Finally, by providing a client-centric approach, Hitachi Energy aims to offer comprehensive advice and support, ensuring that trust and reliability are central to the long-term partnership with CEM.
Fleet Assessment and Transformer Life Extensions help our customers maintain a high standard of energy delivery while contributing to Sustainable, Circular, and Future-Ready Energy Infrastructure.
