CLP Power Research Articles

Go over the mountain and overcome the challenges to power the city

ABSTRACTTo cope with future electricity demand and upgrade power system stability against extreme weather, CLP Power Hong Kong Limited (CLP Power) has developed a new 400kV overhead line circuit. The project involved building a new gantry situated on a natural steep slope, which natural terrain hazards including open hillslope failure, rockfall needed to be addressed. This technical note discussed the technical considerations and challenges to cater for the geological settings, methodologies applied in the geological assessment from desktop studies, site reconnaissance, natural terrain hazard assessment, mitigation measures, foundation design, and the use of Building Information Model (BIM) to enhance project planning and development.

Electromagnetic compatibility of 132 kV power cables in vehicular tunnels

This paper shares CLP Power’s experience in studying the electromagnetic compatibility of 132 kV cable in vehicular tunnels and the mitigation measures to minimize the impact of magnetic fields and induced voltages on communication cables to meet stake holders’ requirements.

From Slim Design, to Strategic Sourcing of Supplier, to Optimised Installation and Commissioning of HV Cable System in CLP Power HK Limited

Driven by ever-changing business environment, technological innovations and changes of supply / demand markets are very common nowadays. These may create either risks or opportunities to power business operators. CLP Power Hong Kong Limited (CLPP), a power utility in Hong Kong, has therefore developed a systematic approach to ensure high reliability o f the High Vo ltage (HV) cable system wh ile driving the cost down. This paper shares CLPP's approach in three key parts, namely prudent design procedures, strategic sourcing of suppliers and installation management. Riding on the technology advancement of cable industry, HV s limCross-linked Polyethylene(XLPE) cable system is well proven learnt fro m the sound experience in Extra High Voltage (EHV) cable industry. The reduced cable size is beneficial for cable transportation, ergonomics and environ mental protection. The Co mpany's 2-level Strategic Sourcing Model helps source price co mpetit ive yet quality suppliers. W ith in-depth investigation in suppliers' long-term sustainability, the suppliers selected through this model created significant saving to the Co mpany without sacrificing system reliability. Together with the optimised installation and co mmissioning practices, the approach has delivered significant contributions to CLPP, such as maintaining high reliability, saving cost, securing cable material supply, and achieving high safety, health, environ ment and quality (SHEQ) performance.

The Conversion of a Hybrid Electric Vehicle into a Plug-in Hybrid Electric Vehicle

Towards low carbon living and clean air quality is CLP Power Hong Kong Ltd. (CLP)'s energy vision and to achieve this goal, the promotion of a cleaner mode of transportation in Hong Kong has been one of CLP's key green initiatives. Recently, CLP has successfully converted a few Toyota Prius hybrid electric vehicles (HEV) into plug-in hybrid electric vehicles (PHEV). Different from the HEV, a PHEV allows the driver to plug into a socket to connect the vehicle to the electrical grid to charge its larger battery pack that replaced the original smaller one. The objective of the conversion exercise is to test the capability and gauge the benefits of the converted PHEV to run on electricity as much as possible, whilst keeping the capability to switch back to conventional combustion engine if required for longer trips. This paper addresses the conversion technical details and shares the operation experience of employing a PHEV in the corporate fleet as well as discusses the underlying business assessment of such exercise. The benefits achieved with the PHEV in terms of reduced emissions and fuel cost savings are also reviewed.

Lessons Learnt from CLP's Smart Meter Pilot

The ‘Internet of Things’ (IoT) connects every day physical objects via Internet Protocols. Smart metering is an implementation of IoT in the energy sector. CLP Power Hong Kong (CLP) launched the 18-month smart metering pilot, named myEnegry Program, in May 2013. The key objectives were to investigate the costs, benefits, and challenges of implementing the smart metering integrated platform, such as seeing if customers are interested in tools and services which can help them conserve energy and to find out if smart metering is technically feasible in Hong Kong's unique densely populated, high-rise environment. This study discusses the technical challenges encountered with networks near customers’ end, namely Neighbourhood Area Network and Home Area Network. Making use of high mobile penetration rates in Hong Kong, user-friendly web portals and mobile apps were designed to allow customers to track their electricity consumption anytime anywhere. Furthermore, CLP paid considerable effort in maintaining cyber security for the network and its data. The myEnergy Program was a rewarding experience for both CLP and its customers, providing many technical lessons learned as Hong Kong begins its journey to a Smart City and embraces IoT.

Terrain Characterisation and Design Wind Profiles for Hong Kong

Numerous wind profiles at different locations in Hong Kong have been obtained from topographical model studies undertaken in the CLP Power Wind/Wave Tunnel Facility (WWTF) at the Hong Kong University of Science and Technology (HKUST). The results of these studies confirm that the impact of adjacent buildings and surrounding topography on the site wind profile is noteworthy and support the addition of more representative wind profiles to the current wind code of Hong Kong, Code of Practice on Wind Effects in Hong Kong 2004 (HK Wind Code 2004), so as to more accurately reflect the site wind characteristics in different regions of Hong Kong. Mean wind speed profile and turbulence intensity profile for three terrain categories, namely deep open sea, harbour-front and built-up, are proposed to be adopted in the wind code of Hong Kong. A case study of wind-induced loads on generic tall buildings with a square cross-section and varying heights demonstrated that the proposed wind profiles provide a more accurate ...

Economic perspectives of aerodynamic treatments of square tall buildings

This paper investigates the impact and value of aerodynamic modifications, based on wind engineering considerations, on the building economics of tall structures. Aerodynamically efficient plan shapes are shown to be an effective means of suppressing wind-induced loads, and hence construction cost, but may come at the cost of reducing both the size and value of saleable/rentable floor area. Therefore, it is not straightforward for engineers to decide on aerodynamic modifications, such as the size and type of corner modifications, with regard to both the structural responses and the effects on economic rewards. A series of wind tunnel tests were conducted at the CLP Power Wind/Wave Tunnel Facility, The Hong Kong University of Science and Technology, using the high frequency force balance technique for building models with different corner modifications. Empirical formulae are proposed to relate the cross-wind responses to the building dimensions and dynamic properties. Those formulations are subsequently employed to assess the financial profits for each building configuration. The construction costs and financial returns of tall buildings are also examined.

Mode shape linearization for HFBB analysis of wind-excited complex tall buildings

The high-frequency base balance (HFBB) testing technique has been developed and continuously improved for two decades. A number of researches have been devoted to the development of mode shape correction factors to account for the significant uncertainties in the prediction of generalized wind forces due to the non-ideal mode shapes. However, these correction factors are mostly derived based on presumed wind loading distributions and/or correlations, which introduce inherent uncertainties associated with the inappropriate modelling of the actual wind loads influenced by the site specific characteristic of the surrounding proximity. This paper proposes a new HFBB analysis method independent of the information of the wind load distributions, referred to as the linear-mode-shape (LMS) method, to minimize the discrepancy in the estimation of generalized wind forces due to nonlinearity of mode shapes. The uncertainties of the translational components of the generalized wind forces prediction are eliminated by linearizing the three-dimensional (3D) coupled mode shapes. A series of wind tunnel pressure tests was conducted at the CLP Power Wind/Wave Tunnel Facility, The Hong Kong University of Science and Technology to determine the distribution of wind loads on an example building, from which an “exact” wind-induced response was computed and used as a reference for the comparison of the LMS method and the conventional HFBB method. The accuracy of the generalized forces prediction, and hence the estimation of structural responses, for buildings with 3D coupled mode shapes was improved. In addition, a parametric study was carried out to examine the robustness and reliability of the LMS method for a range of practical mode shape power exponents. The detailed formulation of the LMS method is outlined in this paper.

Wind-induced self-excited vibrations of a twin-deck bridge and the effects of gap-width

A series of wind tunnel sectional model dynamic tests of a twin-deck bridge were conducted at the CLP Power Wind/Wave Tunnel Facility (WWTF) of The Hong Kong University of Science and Technology (HKUST) to investigate the effects of gap-width on the self-excited vibrations and the dynamic and aerodynamic characteristics of the bridge. Five 2.9 m long models with different gap-widths were fabricated and suspended in the wind tunnel to simulate a two-degrees-of-freedom (2DOF) bridge dynamic system, free to vibrate in both vertical and torsional directions. The mass, vertical frequency, and the torsional-to-vertical frequency ratio of the 2DOF systems were fixed to emphasize the effects of gap-width. A free-vibration test methodology was employed and the Eigensystem Realization Algorithm (ERA) was utilized to extract the eight flutter derivatives and the modal parameters from the coupled free-decay responses. The results of the zero gap-width configuration were in reasonable agreement with the theoretical values for an ideal thin flat plate in smooth flow and the published results of models with similar cross-sections, thus validating the experimental and analytical techniques utilized in this study. The methodology was further verified by the comparison between the measured and predicted free-decay responses. A comparison of results for different gap-widths revealed that variations of the gap-width mainly affect the torsional damping property, and that the configurations with greater gap-widths show a higher torsional damping ratio and hence stronger aerodynamic stability of the bridge.

Simulation of resonance over-voltage during energization of high voltage power network

Under network equipment outage conditions, the system has to be restored to normal operating conditions as fast as possible to ensure the supply security and avoid prolonged interruption of power supply. In the development of the restoration strategy under different contingencies, a wide range of issues are needed to be studied. For different contingencies, it is important that appropriate approaches, tools and study models are selected and used to meet different objectives. The extraordinary system conditions during restoration require special electromagnetic transient analysis with different system modelling methods and system parameters. All these are very different from those studies conducted for normal operating conditions. Field tests of various restoration arrangements also play an important role in calibrating the study models and parameters in order to verify the study results. With all these studies, CLP Power is able to establish practical and reliable system restoration plans.

Hong Kong's electricity market beyond 2008

In Hong Kong, electricity is supplied by two private utilities: Hongkong Electric and CLP Power (CLP). Both are regulated under the Scheme of Control (SOC). The SOC is a formal, long-term regulatory contract of 15 years, signed between a private firm and the Hong Kong Government. Under the SOC, the two electric utilities are subject to both rate-of-return control and price control. The current scheme will expire by 2008. In this paper, we propose a gradual and cautious approach to the introduction of market reform into the electricity industry in Hong Kong. For regulated markets, the government should consider replacing the SOC with performance-based regulation for wire businesses and the non-contestable market. For competitive markets, the government should consider introducing competitive tendering for new sources in the generation market and liberalising the supply market in phases.

TETRA Technology for Power Systems Control & Monitoring

Power utilities have unique requirements for reliable and secure elecommunicauons for the operation and control of their power systems. With the continuous expansion of the CLP Power’s (CLPP) elect...

Corporate Environmental Reporting — The CLP Power Experience

CLP Power Hong Kong Ltd. believes that environmental reporting is a management tool and a means to keep track of and to improve performance. Although it is relatively new to Asian power utilities, external reporting on environmental performance is becoming an international norm. There are some notable leaders in this field including those in Europe and in Northern America. We issued our first external environmental report (which also included elements on safety and health) in 1997 which was the first of its kind by local companies in the Hong Kong Special Administrative Region. Our report in 2000, known as Environment, Health and Safety Review 2000 was awarded the Best Environmental Report from the Hong Kong Eco-business Awards 2000. From our experience, external environmental reporting offers the advantages of maintaining good relations and partnerships with stakeholders, aligning with international best practice, improving environmental performance, and gaining external recognition. In this article, we will present our overall system on environmental reporting, share our experience in the production process of an environmental report with particular focus on the critical elements and considerations involved, and lastly discuss the benefits of environmental reporting to the company. The use of Intranet to facilitate reporting and the computerised information system in CLP Power are also briefly discussed.

Responding to growth — CLP's power transmission and distribution development programme

Electric power distribution over a relatively small, very densely populated and expanding area presents interesting problems to power-system engineers, and requires careful planning in both the long and short terms. This article outlines China Light & Power's strategy for Hong Kong.