Supply Reliability and Power Quality
Find out how we achieve a world-class supply reliability of over 99.999%.
Our world-class reliability rate
We provide safe and affordable electricity at world-class reliability rate of >99.999%. From 2020 to 2022, the average unplanned power interruption duration was 5.7 minutes each year per customer, which was higher than the 0.99 minutes recorded last year. It is mainly due to the impact of a cable bridge fire incident in Yuen Long. If the impacts derived from the Yuen Long cable bridge fire incident were excluded, the three-year average was 1.0 minute.
In contrast, these cities averaged 13 to 31 minutes of unplanned interruptions from 2019 to 2021:
- Sydney’s Central Business District;
- New York; and
- London.
How we ensure power reliability
We take proactive steps to monitor the status of our power system. To ensure the integrity of our power supply system, our crews constantly conduct maintenance and improvement work.
Find out more about our power reliability measures:
Robust system
We operate our systems efficiently through:
- Asset management;
- Operational procedures; and
- International best practices.
Our network is also connected to Guangdong’s power grid and Hong Kong Electric. This enables mutual support during emergencies and reduces electricity reserve requirements.
Emergency preparedness
Our emergency crews are available 24/7 responding to all types of emergencies. We conduct regular emergency drills on typhoon, rainstorm, chemical spillage and fire. During each drill, we test our system's effectiveness in:
- Efficiency;
- Co-ordination; and
- Communication.
In the event of supply interruptions, we strive to restore electricity as soon as possible.
Vegetation management
Hong Kong has a wide coverage of trees, many of which are fast-growing species. Power failure may occur when vegetation contacts with overhead lines. This could happen due to windy weather.
In 2001, we set up a task force and adopted systematic vegetation management regime. With scientific techniques, we protect overhead lines and vegetation at the same time for mutual benefits of the public.
11kV Live line work
In 1999, we introduced 11kV Live Line Work (LLW) to:
- Minimise supply interruption time; and
- Enable more flexible maintenance and repair schedules.
This well-developed technique helps us to improve customer satisfaction and work efficiency. To date, we have 5 LLW teams with 20 live line workers.
Power quality services
We offer customers a wide range of power quality services to enable sensitive equipment riding through voltage dips. As overhead lines form a major part of our supply network in rural area, which are more vulnerable to adverse weather conditions such as typhoon and lightning. We minimise these voltage dips through vegetation management and lightning protection.
