Located next to container terminals, TP-Singapore DP comprises of two 5-storey blocks offering 60,000m² of prime logistics space. This facility had an existing power system with 6.6kV feed from port. PowerQ’s role for Phase 1 was to evaluate current power demand and forecast future demands.
PowerQ evaluated multiple options for upgrade and prepared a detailed feasibility report.
Phase 2 of the work involved engineering design, liaising with utility distribution company, tendering and project management services. The system was upgraded to; 22kV feeders supplied from a new source, a new 22kV substation was built, an old 6.6 KV transformer was replaced with 4x2.5 MVA ONAN transformers, 22 kV ABB switchgear and a replacement of 4000 amp low voltage bus duct. Other than that, as part of the upgrade, the facility was installed with emergency diesel Genset to supply emergency loads.
The challenge was to create a parallel power system and transfer the power from 6.6 kV to 22kV during weekend/overnight shutdown to minimize the affect on ongoing work. The engineering contractor, Shinryo took care of all safety precautions to avoid disruption during power transfer by incorporating contingency measures such as portable gensets. The project involved as well an upgrade and alteration of other systems such as fire protection and ventilation system.
PowerQ evaluated multiple options and recommended the approved option for HVAC and electrical system for this 2 million Sq ft facility. PowerQ prepared the construction documents (drawings, specifications, cost estimates, design analysis) and performed construction services for the design of Electrical, ACMV, BMS and Fire Alarm system. The AC system has a capacity of more than 4000 R. Tr. and Electrical connected load is more than 12MW.
The design involved heat load calculations, electrical load calculations, power system study using SKM Power Tools software to evaluate short circuit levels and production of schematic, layout and detailed floor plan for tender bid package.
Preliminary sizing, design and cost estimates were prepared to provide an emergency engine generator (EG) to support portions of the HVAC equipment when normal utility source power fails. The ACMV system employs central pre-cooled fresh air and central chillers.
Based on the design specifications and drawings developed by PowerQ, the owner-India Land, awarded various contract in technical consultation with PowerQ for equipment from company such as Trane, ABB, Mitsubishi etc.
HFC in Singapore structured of twin office towers with floor area of more than 30,000 sq meters consists of blue-chip companies.
This high rise towers required additional electrical power upgrade to meet increased demand created by modern offices and computer systems. On the other hand, the reliability of power system need to be enhanced due to the new installation of 22KV transformer and LV Switchboard and tied with the existing system.
PowerQ worked with engineering contractors, switchboard manufacturers, facility team, structural engineers and statutory agencies to ensure that the shut-down for the upgrade will not exceed more than 8 hours as per client's requirements.
VT Expansion included a new 22,000 cubic-meter Third Party Chemical Tanks in Singapore.
VT expansion project had included additional 18 tanks with associated processes and utility systems. The raw material is generally offloaded from ships and transferred to storage tanks and finally to trucks through pumping systems which are monitored and controlled by a custody metering and system.
The EPC contractor engaged PowerQ to provide engineering services for electrical and instrumentation system. PowerQ reviewed the other similar terminals and studied the existing facilities. We had designed the electrical and instrument system for storage of multi-specialty chemicals for Vopak terminal.
PowerQ developed design documents for:
PowerQ reviewed the existing system and liaised with vendors and term maintenance contractor to produce improved design documents to integrate with the existing system.
The Dubai Mall in UAE, is one of the largest malls in the world. The mall is a part of ’Downtown Dubai’. PowerQ was engaged by consultants to analyse and study the potential impact of the strong electromagnetic field generated by the transformers, associated power cables, bus-ducts and switchgear.
In large commercial buildings where offices and work areas are located near electrical systems such as transformers, switchgears, bus-ducts and electrical panels, the occupants are usually exposed to a very high 50Hz magnetic field levels ranging from 10-1000 mG (milligauss). Fortunately, magnetic field strength rapidly diminishes as a function of distance from the electrical source. However, approaching the 50Hz magnetic sources, the occupant may be exposed to extremely high 1000-100000mG levels. Occupants are not aware of this potential hazard unless the magnetic source produces electromagnetic interference (EMI) in sensitive electronic equipments such as monitors, magnetic media, audio/video equipments etc. Once detected, 50Hz magnetic field management (mitigation) ultimately becomes the responsibility of the building's management.
The project team were concerned on the potential impact of strong Electromagnetic Field (EMF) generated by transformers, switchgears, bus-ducts and associated main cables at the proposed 4-storey shopping mall. The transformer rooms and switchgear rooms are proposed to be located at the lower ground floor while retail space is designed above the transformer.
PowerQ reviewed the drawing and specifications of installation before work could start. We had provided recommendations to mitigate strong magnetic field near sources such as 132 kV transformer sub-station, high amp cables carrying thousands of amperes and segregation from potential victim equipments.
PowerQ had performed power measurements on Switch Boards to determine the sufficient margin of capacity for future upgrade.
The power monitoring was conducted at Main Switchboard and SSB using Power Quality Monitor - Fluke 434. The objective was to carry out a power measurement with a view to determine the sufficiency of the existing Switchboards before installing any additional load.
- Determine maximum demand and various parameters
- Acquire and analyze data
This scope of monitoring is limited to MSB and SSB. Electrical supply was continuously monitored and parameters such as Maximum Demand, THD, Voltage and Current were captured and tabulated and issued as report.
Designed by renowned architect Zaha Hadid Ltd-UK, Chennai Tech Park is located in Ambattur Chennai. PowerQ was contracted to perform a feasibility study and design Integrated IBMS including chiller and security system.
This 2-million sq feet IT space is located in 3 towers. The goal of this project was to provide reliable control solutions that is able to remotely monitor and utilize to reduce energy consumption base-wide. The overall system is connected to the TAC BMS. This allows the Facility Managers to have capabilities to monitor and control from a remote central operator workstation.
Description of services performed:
- Full site survey
- Feasibility study
- Existing conditions report
- Cost estimate
- Life Cycle Cost Analysis
- Cost avoidance analysis
- Control system design
- Installation details
- Sequence of operations
The interconnected power system is considered as the largest and most complex machine. Power system analysis of interconnected or islanded system is concerned with understanding and operation of the system as a whole. The advancements in power systems and computerized analysis of them have taken a leap in the recent years. Power System Analysis is used for regular operational studies like load balancing, load forecast as well as for pro-active and planning studies, where they can alleviate/ prevent catastrophe.
With loads which could be more diverse equipments, the challenging problem in Power System Analysis is to appropriately model all the system components to get the aggregate effect. This article focuses on certain non-typical Power System studies encountered by PowerQ over the past one and half decades of experience primarily with oil and gas industry, mobile and fixed offshore systems. Apart from steady state analysis of power systems, in practice they undergo changes due to change in loads, outages of equipments due to maintenance or disturbances, such as equipment failures, live faults, lightning strikes or any number of other events. Extremely fast Electro-Magnetic transients, undetectable leakage currents, persistent harmonics, protective relay settings for different operations on site during commissioning are few of the peculiar experiences which have been discussed briefly in this article.
This will give an insight of the practical problems faced along with reasonable solutions that may guide/ be helpful to students, prospective engineers with an urge to elevate in this field of engineering/ power system analysis.
This document presents few of the practical problems in power systems experienced on site. Electro Magnetic transients, harmonics, TRVs are to name a few. It is essential for systems located in a place with high lightning activity to have appropriate lightning and earthing protection and electronic surge protection.
These systems should also thoroughly be referred against standards for their design and installation. Similarly, effects of harmonic voltages and harmonic currents are significantly more pronounced on marine generators due to their source impedance being typically three to four times that of utility transformers. The major impact of voltage and current harmonics is the increase in machine heating caused by increased iron losses, and copper losses, both frequency dependent In addition, there is the influence of harmonic sequence components, both on localized heating and torque pulsations.
Harmonic, in addition to causing additional heating, can create mechanical oscillations on the generator shaft. Another important phenomenon in a power system is Transient recovery voltage which is contingent upon the circuit conditions and parameters of the circuit, thus making it essential to study them for application of circuit breakers.
Generally, circuit breakers in a system are applied based on available short circuit capability at that point in the circuit. But, when circuit is interrupted it results in a TRV, this has deleterious effects on the circuit breaker. Thus TRV is a decisive parameter that limits the interrupting capability of a circuit breaker.
A review study for the west Natuna Sea, Indonesia records a relatively high lightning activity, where the gas field is situated. Weather is hot and humid and conditions are favorable for the development of lightning producing cumulonimbus clouds.
The destructive power of lightning is so tremendous that apart from igniting forest fires, damaging electronic equipments, disrupting electrical power and telecommunication system, they may cause fatality either directly or indirectly. Hence, the gas field in west Natuna Sea needed a detailed review of the design, construction and installation of the lightning and earthing protection system to be deployed for it. A clear practical recommendation was also needed based on the existing project status.
The platform built for drilling was built of steel with all major structures firmly welded to the deck. Earth bars were bonded to platform legs. Our experience with other projects added value in assessing this platform. The general observations from our experience shall be revealed that certain structures and equipments are usually not provided with lightning protection. The list of observations is as follows:
1. The external metal parts such as crane flare stack and generator exhaust stacks and telecom antennae are usually not provided with any air termination, down conductor or lightning arrestors.
2. The main earth bars are welded to structure while the panels and equipment are bonded to deck or earth bar by means of compression gland.
3. Surge Protection devices are not applied to Low voltage distribution panel supplying lighting and power socket outlets.
4. The cranes are not provided with any lightning arrestor or air terminals.
5. The CVT is not installed.
6. Also in our experience on other offshore projects involving drillships, semi-submersible vessels and jack up rigs, we have not observed any lightning protection system on certain projects.
The west Natuna Sea, Indonesia records a relatively high lightning activity, where the gas field is situated. The gas field once operational would bring gas to Singapore via 300km long subsea pipeline. Weather condition at this place where the CPP and WP is built is favorable for the development of lightning producing cumulonimbus clouds. The destructive power of lightning is so tremendous that apart from igniting fires, damaging electronic equipments, disrupting electrical power and telecommunication system, it may cause fatality either directly or indirectly. Hence, the gas field in west Natuna Sea needed a detailed review of the design, construction and installation of the lightning and earthing protection system to be deployed for it. A clear practical recommendation was also needed, considering the mid-way construction of the facility.
The platform for drilling was built of steel with all major structures firmly welded to the deck. Earth bars were bonded to platform legs. The design company had considered the standards IEC 62305, IEC 1312-3, API RP 2003, BS 6651:1992, UL 1449, IEC 61024-1 and NFPA 780 for applicable rules and regulation in the design, installation and maintenance of the systems on-board and to minimize the effect of lightning strikes on humans and materials. The real challenge was to evaluate the then existing design of the project whose construction was mid-way and make feasible recommendations should there be any short coming.
Findings By PowerQ:
The standard considered was IEC 62305 which is for on-shore systems. It was recommended to refer IEC 61892.
Lightning Protection zone: All panels were listed as in inner zone, away from direct lightning strike but should also have listed the equipments in zones of direct lightning strike.
Assessment of external protection:
1. The lightning density had to be confirmed which according to LPATS, is≥60 strikes/ km2/ year.
2. IEC 61892 was used as basis for protection.
i. External Lightning Protection (LP) was not required as against IEC 62305, which recommends air termination system for WHP & CPP. IEC 61892 says that on well-bonded platform the panels and equipment system will not be exposed to direct lightning strike and the air terminals are optional/ additional measures.
ii. Instruments, equipments and panels not protected or installed in grounded or installed in grounded metallic structure and prone to direct stroke to be listed.
iii. SPD selection should ensure that temporary voltage variation due internal switching transients caused by starting motors, transformers, photocopiers, or other loads on and off shall not trigger SPD’s.
iv. The connection of earth bar to other earth bar and platform legs were not by welding which ensures better bonding. The earth connection to equipment and panels were not by compression gland.
Recommendations By PowerQ:
A prudent approach to risk management of the lightning hazard is by being proactive and to apply legitimate defences.
1. Harmonise various document to IEC 61892 standard for lightning and earthing protection.
2. External and Internal lightning Protection
Lightning protection should be made in accordance with IEC 61892. CVT proposed was not recommended as per IEC, NFPA or other standards and also as the project was in construction stage. Platform should be well bonded.
Air terminal was not recommended for the generator and compressor exhaust stack as per IEC 61892, which is applicable to offshore platforms. Platform shall be well bonded and structure shall be protected against lightning strike. It was recommended to bond stack and cladding of stack to support structure and main deck by welding.
· Similarly, air terminal for crane and flare stack on was not recommended. Considering that fixed part of crane was welded to structure, it was recommended that movable part of crane and rotating upper part of the crane to the platform shall be bonded. Also electrical and control panel for crane shall be protected with SPD.
· For the crane operator cabin, it was recommended to bond to structure. Air termination was not required as cabin it reportedly made of steel.
· For generator control panel which could not be installed with SPD for design reason, it was recommended that the panel not be installed on enclosure wall to avoid reduce secondary electromagnetic effect of lightning strike and to bond the enclosure. Any cable to this panel exposed to outdoor was recommended to be installed in cable trunking or tray covered with metal covers and shall be bonded.
· Considering criticality of the telecom antennae it was recommended to install air terminal for radio telecom and TV antenna installed on the LQ Roof as an additional protection measure. The air terminal may be bonded by down conductor to nearest welded structure on deck.
3. Equipotential Bonding
Poor bonding may result in voltage rise mismatches, which in turn may lead to “arcs and sparks” on sensitive low voltage equipment.Without effective bonding, any lightning protection system will not work therefore following measures shall be adhered to:
· Bonding shall be made locally in close proximity to the items, which require bonding.
· Normally bonding connections shall be made by bolted connections to steel pads (earth bosses) which shall be welded to the steel deck or structure.
· For equipment installed on deck to use stainless steel boss for earthling for corrosion protection. Every bonding connection to earth shall be of copper or other corrosion resistant material and shall be securely installed and protected against damage and galvanic corrosion.
· Lugs may be of copper or its alloy and shall preferably be of the serrated contact type and effectively locked. Connections shall be secured against becoming loose due to vibration. Earth cable shall be installed with slack.
· Advise to produce quality control document to ensure that the grounding system is bonded as per design.
There is concern over earthing and lightning protection of crane, Generator and compressor panel and instruments for flare and flow metering and risk of direct strike and secondary effects of lightning currents.
· Flare boom, drilling rig or crane shall be bonded to the main structure. If satisfactory conductance through the structure is not achieved, additional earthing conductors shall be installed where necessary.
· Where possible isolate all wire-line communication services from remote ground with optical devices or isolation transformers.
· Minimum cross section in the local earthing shall be as per IEC and copper wire 6 mm2 due to mechanical strength.
5. The connection of earth bars and platform legs shall be by welding for better bonding. The earth connection to equipment and panels may be by compression gland. The main earth bars shall be solidly earthed via connections to a minimum of two earth bosses for each earth bar, cad welded to the main platform structure.
6. Surge Protection Devices
· A further rational approach was recommended for application of SPD. A coordination table shall be produced by the supplier of SPD.
· Installation practice and relevant code such as IEC62305-3 and 62305-4 to be followed for SPD installation.
· It was recommended that additional SPD may be applied to downstream boards if they support electronic load equipment and to confirm that the short circuit KA rating for SPD was coordinated with the panel kA rating.
· Install SPD with a Circuit breaker or fuse for isolation, protection to avoid damage to SPD.
· It was recommended to bond panels prone to direct strike of lightning by cad weld where SPD could not be installed and the cables to the panel to be installed in metal trunking or metal covered cable tray.
· The protection of electrical and electronic equipment located in equipment rooms should be a combination of the following:
· Bonding of all metallic components entering an inner zone from an outer zone
· To install of SPD on all cables entering an inner zone.
· Bonded enclosures to act as magnetic shield.
7. Personnel protection from Lightning Strike on platform- People must avoid being a part of the current circuit path. It was recommended that personnel protection from lightning and evacuation shall be covered under platform Operation and maintenance manuals and Environmental Health and Safety (EHS) procedures.
8. Cable Routing
· Routing outdoor cable as far as practicable, in covered areas or area along a metallic vertical structure where there is lesser risk of the cables.
· Cables for telecom antenna shall be installed in a metal covered cable tray or metal trunking.
9. Testing and Quality Control
· Detail out specifications for testing of bonding system. The earthing bonding inspection shall not rely on a visual means to confirm that a ground clamp and lead are in place for proper grounding or bonding, with confirmation via resistance meters.
· The flexible leads are subject to mechanical damage, wear, corrosion and general deterioration. Hence, recommended to be tested and inspected frequently.
· This quality control inspection should evaluate cleanliness and sharpness of the clamp points, stiffness of the clamp springs, evidence of broken strands in the cables, and solidity of cable attachments.
· A more thorough inspection to be made during commissioning and periodically during maintenance, using an intrinsically-safe ohmmeter to test ohmic resistance and continuity.
· Provide documentation for precautions during testing of panels with SPD.
10. Lightning strike can cause secondary effect such as interference to communication, and Audio video system. An effort shall be made to confirm Electromagnetic Compatibility (EMC) compatibility of systems such as Satellite communication, on site walkie-talkie system, CCTV system, Public address and telephone system.
The WHP was relatively at less risk due to smaller size and shorter structure than CPP.
The WHP was also metallic structure and was covered by crane. It was recommended to follow the same protection philosophy as CPP. It was recommended to identify any critical system such as ESD, PSD system installed on WHP.
Transient recovery voltage is the transient across a circuit breaker. TRV is a decisive parameter that limits the interrupting capability of a circuit breaker.TRV manifests in different ways depending on circuit configuration, hence the objective of this report is to study the effects caused by the TRV and to validate the suitability of the proposed circuit breakers or other alternatives to reduce the effects of TRV in case it exceeds tolerable limits in the LNG plant under study. LNG Plants involve electrical system with many trains and may need a longer transmission of power between trains. They also have more reactive loads. Hence, effect of TRVs on the CBs of such system is critical in making the choice of CBs.
The TRV ratings define a withstand boundary. A circuit TRV that exceeds this boundary is in excess of the circuit breakers rated or related capability. However, the study shows that the highest TRV obtained is 19.3kV and is within limits of the Circuit Breaker TRV capabilities (23.5 kV) as per IEC IEC62271-100.
As the withstand boundary, including the time to peak and RRRV are within limits with adequate margin, the proposed selection of the 11kV Circuit Breaker is acceptable for use in the LNG plant.
The power system of this LNG plant need not be proposed with methods to reduce the effect of TRV. The reasons for TRV being within the limits are that the loads are concentrated in a small geographical area and are not capacities. However, system involving long transmission lines, high capacities loads, plants at direct-stroke lightning prone areas, cases involving transformer inrush during energisation etc. may have intolerable TRVs in the system and may need suitable remedy.