SP PowerGrid – On Power Quality

As a subsidiary of Singapore Power Group, SP PowerGrid manages Singapore’s electricity network with exceptional network reliability. Despite all its transmission and distribution network are placed underground, giving an immunity to lightning or other adverse weather conditions, SP PowerGrid has taken utmost care on power quality issues such as voltage dip. This is imperative due to the increase in high-tech industries, particularly semiconductor fabrication, petrochemical and pharmaceutical industries which demand high-precision control that is highly sensitive to voltage fluctuation.

With that in mind, SP PowerGrid set up Power Quality section to develop state-of-the-art technology which in turn provide improvements and monitor power quality performance across the nation. In this article, several initiatives will be briefly covered and in the last paragraph, we will take a look at an initiative taken by Australia in improving its network reliability. [1]

Power Quality Monitoring System

This is an island-wide system which records and analyzes the magnitude and duration of a voltage dip. The data will be publicly available for customers and investors alike to refer to while designing their equipment and installing adequate voltage dip ride-through. The monitoring system consists of monitoring blocks which location based on its network configuration, major customers’ locations, geographical coverage, type of load, and its capacity.

To achieve such capabilities, the system require two major requirements:

  1. The center must be able to quickly retrieve the distorted waveform in case of voltage dip
  2. The main database must be open and independent of the vendor providing

The second requirement allows data from different manufacturers to be stored, retrieved, and analyzed.

After the data is retrieved from the disturbance point, power quality software immediately analyzes and produces summary report on the event based on Power Quality Performance Index e.g. System Average Interruption Duration Index (SAIDI), System Average Interruption Frequency Index (SAIFI).

Application of Mitigation Technologies for voltage dip ride-through

SP PowerGrid also conducts test on application feasibility of available technologies. Lessons are learnt from this test including:

  • Reliability of power electronics components
  • Understanding of dynamic load characteristics
  • Fine-tuning of power quality device protection
  • Consideration of foot-print relating to space availability

Taking those lessons into account, another subsidiary of Singapore Power, Singapore Power Systems, developed a new range of voltage dip compensators – the single-phase DynaCom. The DynaCom deals with voltage sags by injecting a compensating voltage into the power supply, effectively substituting the voltage sags. The impressive thing about this is its ability to respond and compensate within 2 milliseconds for a voltage dips as low as 40 per cent nominal voltage up to 1 second. [2]

Network Enhancement

Voltage dip mitigation can also be done by restructuring the electricity network. Realizing from the benefits of having dedicated supply, SP PowerGrid introduced a 400kV transmission system in 1998. This new transmission system enabled PowerGrid to split the 230kV network into two electrical blocks, the North and South blocks. This significantly reduced the severity of electrical fault happening in one block seen by the other block. It has been proven in actual incidents in 1999 and 2000 due to faults between Senoko and Kallang Basin. In 1999, the Southern block would experience a dip of about 30% to 58% but with the new system, it would experience a dip of about 12% to 17%. [3]

Cost-Effective Mitigating Solutions

Comparing with network-based solutions, in-plant solutions are more cost-effective. Devices like coil-lock, constant voltage transformers, and low voltage sag compensators are effective for localized use and widely available in the market. Singapore Power itself provides financial incentive to industries to implement such solutions.

Cable Damage Prevention

Damaged cable is another contributing factor to power quality problems. SP PowerGrid has set up a Cable Damage Prevention Unit (CDPU) to prevent cable damage. This unit performs patrolling around major earthworks, advising contractors on conducting preventive measure, and giving dialogue sessions with consultants and developers around the issue.  It is proven effective as the number of damage on transmission cable was reduced from 4 to 1 case annually in 2000.

Conclusion

In summary, these are some of the initiatives SP PowerGrid has taken:

  • Routinely monitor power quality disturbance in the grid
  • Research & development of the latest power quality devices
  • Analyze the network for future upgrade possibilities
  • Incentivize in-plant solutions for other industries
  • Raising awareness of and preventing cable damage due to earthwork

Singapore has topped 22 global cities in network performance, and achieved 0.31 minute per customer per year for SAIDI, and 0.007 interruption per customer per year for SAIFI.
Pretty awesome, huh.

Power Quality in Australia

Similar to the Power Quality section in SP PowerGrid, Australia also established Australian Power Quality & Reliability Centre for research, education, and consulting in T&D system power quality. It collaborates with the electricity distribution industry to improve the quality and reliability of the overall supply for the customers. The center is also actively involved in industry bodies and standards organizations such as Standards Australia, IEC (International Electrotechnical Commission) and CIGRE (International Council on Large Electric Systems). For further detail, please refer to [4]

References

[1]S. T. Chang, K. Y. Chua, C. C. Siew and T. L. Tan, “Power Quality Initiatives in Singapore,” SP PowerGrid Ltd, Singapore, 2001.
[2]Power Engineering Int, “Power Engineering Int,” 2 October 2002. [Online]. Available: http://www.powerengineeringint.com/articles/2002/10/new-voltage-dip-compensators-from-singapore-power-division.html. [Accessed 27 February 2016].
[3]K. Y. Chua, C. C. Siew, B. H. Li and T. L. Tan, “Network and Plant-End Power Quality Solutions,” in International Power Quality Conference, 2002.
[4]University of Wollongong, “Australian Power Quality & Reliablity Centre – Home,” 14 January 2015. [Online]. Available: http://www.elec.uow.edu.au/apqrc/home. [Accessed 28 February 2016].

Hi, folks! Thanks for dropping by! This article is my submission for Assignment 1 of EE4534 Modern Distribution System with Renewable Resources System. I just thought it would look pretty neat to upload it somewhere so I decided to post it here. I hope this helps you understand more about SP PowerGrid initiatives on improving Singapore network reliability. Please like and/or share it too!

Starting March, I will start something new here. Stay tuned and remember to follow Spark It! My Way 🙂

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Author: Arga Roh Sahrijal Saragih

I love to learn. I love to code. I love to read. Gonna be a professional Software Engineer. Happy to sing and to write. Enjoy a good company. Prefer tea. Manage an online library at https://instagram.com/ruangbaca__

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