2SIndustrial Power Controllers and Monitoring Systems Email: erazmus@wantree.com.au Network Power Systems/Network Computers Kampong Mendulong Site Report Page /6 ^(2Ze5(CPBrush 0 0 689 60BM>(<??????????????|x>?|???<????????p??p?~p??0~p?~p<0A| <8C|!?<I;8C|!><8C|!~<x?<~<|?x?>?||?x>?|?x|>|>9>|x??8`?<~|??8`>~???x`@`?~??@~?@`?????~?A`?????????????14th July 1998 PO Box 491 West Perth 6872 Western Australia Reference: /SEB/MENDLONG Ph and Fax +618 9444 8961 Fax only +618 9384 0861 Report: site works, Kampong Mendulong 26 March to 22 June 1998 Introduction This report describes site works undertaken at Kampong Mendulong (25Km from Sipitang,Sabah) during the period 26 March 1998 to 22 June 1998 to bring the Remote Area Power System (RAPS) to full automatic mode of operation. Two new types of controllers were installed to rectify the problem with the erratic Saft Nife battery charger. A new processor controlled Automatic Voltage Regulator (AVR) and microprocessor controlled Battery Charge Regulator (BCR) designed by Network Power Systems were installed and implement a very stable feedback loop through digital communications between the two modules. This allows very precise control and straightforward reprogrammability which could also be used in the event new battery technology replaces the original vented lead acid batteries. 1. Initial Conditions - 26 March 1998 System supplying power from engines alternating on 8 hour timers with engine operation normal though on very light load during the day (<10Kw) and slightly higher load during late evening (20 to 40Kw), various engine and power statistics recorded. PLC and all automatic systems off. Batteries fully discharged with varying levels of electrolyte, most below the level of plates but visible - voltage across batteries 16v (normal range is 235 - 300v), batteries were therefore sulphated but to unknown degree. Battery specific gravity readings were recorded. Existing Saft Nife battery charger could not be used (even at lowest setting) to put minimal charge into batteries preparation for efficient test installation of new equipment. 2. Installation - 27 March to 6 April 1998 Mounted PVC ducting for additional control cables between engine container and electronics container, fully disabled the inoperative Saft Nife battery charger. Wired several additional control cables for the new processor controlled Automatic Voltage Regulators (AVR) and interfaced these to the main electronics control cabinet. Mounted and wired in one new AVR on wall of engine container adjacent to 3-phase fan. Disabled old Genaust AVRs. Disabled battery charger contactor K3 to ease manual testing since PLC program changes were not initially accessible. 3. First trial of new charge system - 6 April 1998 Connected PC laptop to AVR on diesel engine 1 (Laptop operating in electronics container with RS-232 serial link to AVR within engine container). Whilst manually controlling battery charger main contactor, charging was started and PWM control tests performed successfully - this verified the AVR was correctly controlling the engine and confirmed the ability to perform fine changes in current/voltage control with full and safe stability. Batteries took 2 to 3 hours before current reached 100Amps whilst voltage maintained at 300V DC, charge current versus time was recorded to analyse state of battery sulphation. Next one and a half weeks were spent in bringing batteries to suitable state of charge to enable checking of inverters - which performed satisfactorily. By this time batteries had recovered significantly and were suitable for the next stage. Calibration data on AVR Pulse Width Modulation (PWM) versus current/voltage recorded for full range of operation at 250Amp and up to 273Amps. Some initial engine smoking was observed when charging over 200Amps but this reduced after approximately 30minutes which is consistent with diesel engine characteristics when used lightly loaded for long periods. As first AVR test was successful then second AVR for diesel engine 2 was installed and tested. Occasional early tripping of 150Amp/phase AC breakers was noticed during charging and decision to change to 250Amp/phase on next visit to Kota Kinabalu. 4. Battery Charge Regulator Initial Tests - 20 April 1998 Calibration tests on new Hall effect sensor and experiments to determine best place to mount given high magnetic fields from Saft Nife transformer. Calibration tests on BCR algorithm for current versus AVR control signal and experiments in setting maximum charge cell voltage with Amp Hour accumulator to record charge stored. Implementation of various end of charge conditions and calculation and implementation of cable compensation at level of 0.5volts/20 Amp DC charge. 5. Programmable Logic Controller (PLC) - 21 April 1998 The PLC determines the cycling of the engines, contactor charge cycling and handles fault conditions, this was not operating to specification due to changes made when it was originally discovered the Saft Nife rectifier was inoperative. Several PLC program changes were implemented to return the PLC program to specification and added logic to interface with the new charging scheme. Tests were performed for the following 5 days and it has been determined that the procedure to reset the PLC after a fault be amended to ensure no lingering internal memory retention - ie Turn the PLC off completely for at least 20 seconds after resetting any system fault. 6. Automatic cycle test - 28 April 1998 First test of completely automatic cycle was successful and associated test protocol document completed and supplied to JRC. Copy made for Sabah Electricity Board (SEB) and supplied to SEB during subsequent meeting at Kota Kinabalu. 7. Battery capacity cycle tests - 30 April 1998 Following two weeks were spent in checking battery state to assess whether system was capable of higher charge currents. Cell number 103 was low on capacity and a replacement cell was organised from Sandakan which was in a 'dry charge' state. After installation, care was exercised to ensure this new cell was properly commissioned in accordance with procedures when acid is first added to a dry charged cell. All cells show signs of degradation due to long periods without being cycled, some recovery will take place now that system can properly charge them. System exception alarms were tested and adjustments made to timers for low electrolyte, high voltage and high current. 8. Contractual changes - 13 May 1998 JRC changed the terms of the contract without informing me and refused to pay my fee for successful completion. Having then been informed by JRC that I would only be paid upon formal visit and approval by SEB officer I decided to stay at site and observe the continued commissioning of the replacement cell and occasional automatic cycling to ensure all operations proceeded without exceptions. 9. Enhancements to charging algorithms - 19 May 1998 During the following 2 weeks it was observed that the battery temperature would creep up after several charge/discharge cycles and reach levels which were not helpful to ensuring longest life. One reason for this heating is the plywood boxes surrounding each cell - these act as good insulators but were considered by JRC to be impractical to remove. The other reason for the heating is the sulphated state of the batteries. I decided to enhance the battery charge algorithms to minimise heating effects and conducted several experiments to determine best charge rates with minimal heating. The final charge algorithm handles very well the sulphated state of the batteries but I still recommend the plywood cladding be removed as soon as possible such that the batteries have every opportunity to cool and thereby increase the charge storage efficiency and maximise service life. 10. Record/Display aids to site trial - 7 June 1998 As an assistance to recording data for the forthcoming 7 day site trial I decided to keep a record of charge discharge cycles in the screen display of the BCR. The last 4 charge/discharge cycles are shown and period of time since completion of the last cycle - this allows approximately the last 36 to 48 hours to be recorded in the display as an aid to site monitoring and diagnostics in the event of tracing a system fault. This feature has been retained and can be used by the SEB during normal site visits to keep track of performance. Test Report completed for enhanced features and additional alarm monitoring and supplied to JRC, with copy to SEB. 11. Seven day full site trial and load monitoring - June 1998 This proceeded very well indeed and the system performed flawlessly in full automatic charge/discharge cycles. Site data was recorded by Rosli Mustafa of JRC and it is my understanding that he will supply this to Sabah Electricity Board, unfortunately I was unable to obtain a copy since his episode with suspected malaria and subsequent flu but, expect to receive a copy soon when he recovers. 12. Final site commissioning and data record - 22 June 1998 Final site visit, all containers cleaned and records made of all meters and operational parameters. System left in full automatic mode, operation normal. A. System Status The system has been left in a state where it is operating reliably and at a capacity suitable for supplying the village at its current load and suitable for expected increase in load demand for the next 12 to 18 months provided it is properly maintained with particular attention to the batteries. Given the fact that the batteries were previously not fully charged for long periods has resulted in a loss of an estimated 25% in battery amp hour capacity from a nominal 800AH to approximately 600AH. Battery sulphation has resulted in higher station losses and is estimated at 30%, this can be improved either by possible chemical treatment of the batteries, incremental cell replacement or complete battery replacement. The Battery Charge Regulator control algorithm can be upgraded to cater for any type of battery technology. If the SEB decide to change from vented to sealed lead acid batteries then the BCR charge algorithm can be easily changed. There need not be any other changes to engines, alternators, controls or inverters except for normal maintenance. B. Short Term Recommendations The following recommendations have been determined as the minimum efficient and cost-effective to prolong system life and improve the reliability of village supply. Long term service recommendations (especially in respect of alternative batteries) could be made and this information will be made available upon request. B.1 Remove plywood boxes around batteries to allow batteries to properly cool. B.2 Attend to battery variations, it was noted that certain cells are operating at higher temperatures than others - these should be monitored on each visit and be the first to be replaced or chemically treated. B.3 Service engine starter motors - particularly engine 1 which seems to have a bad spot on the brushes since on occassion it refused to crank. B.4 Add a self reset fault controller to put the system back into automatic mode in the event there is a transient inverter overload which is not catastrophic. B.5 Provide an alarm condition for high battery temperature. B.6 Repair terminals on the 24v sealed lead acid standby batteries in the electronics cabinet - these batteries may also need to be replaced. B.7 Consider obtaining a 'single cell commissioning charger' for cell replacement. B.8 Add a low cost dot-matrix printer to the BCR to record cycle information, this would be used to maximise the effectiveness of each site maintenance visit. C. Application to other sites in Sabah All site work undertaken at Mendulong is immediately applicable to the other four 250Amp sites and one 150Amp site requiring repair in Sabah. This first trip to Mendulong tested the viability of a new and improved charging technique and additional time was spent in several extra experiments to assure SEB of stable operation and longest service life. Equipment for the other sites is being fabricated in Perth, Western Australia and will maintain the initial repair schedule but given the changes with JRC then formalisation of an arrangement with SEB will need to be made before delivery and commissioning of other sites. The SEB can be assured that upon completion - all the sites will behave in the same manner which simplifies servicing and maintenance requirements in the long term and proves the value of Remote Area Power Systems as an auxilliary power delivery system in Malaysia. D. Spare Parts A complete set of spare parts for the AVR and BCR is currently in preparation and will be ready for shipment in accordance with the planned site repair schedules for all other sites. Spare parts for the other components (which would normally be supplied by JRC) can now be fabricated in Perth, Western Australia from existing schematics and information obtained from the next site visit. Network Power Systems is also able to support spare parts for the inverters and relate requests for any engine requirements to "Concept Diesels" in Perth, Western Australia. Incidentally, if any of the six RAPS sites is upgraded with a new set of batteries, then the best cells which have been removed can be reconditioned and used as spares for the other sites. E. Miscellaneous Several photographs were taken of the progress of site works and are available in electronic (digital) form via email or on a series of IBM PC compatible floppy disks. Journal logs were kept of all calibration and stability experiments. Please contact the author of this report with your request. F. Service Management Plan Given the changing circumstances of the principal contractor JRC. Network Power Systems would be delighted to offer a service and support management plan to ensure the Sabah Electricity Board would achieve the highest level of support, improved system specifications and extended support beyond their initial contract. G. Year 2000 Compliance All timers and clocks used in the AVR and BCR and test equipment used on site to record calibration and any associated equipment is fully qualified and approved to be Year 2000 compliant. Copy of certificate can be supplied on request. H. Documentation and Equipment Manuals Mr. Hasly, manager of SEB office in Sipitang has been supplied with two copies each of the AVR and BCR manuals and site test report. A troubleshooting guide can be supplied together with drawing amendments and updates, call for your request. Conclusion Site repairs have successfully brought the Remote Arear Power System at Mendulong to operating specification, the new equipment allows an increase in specified charge by 20% (up to 300Amps DC) to reduce charge times and system operates reliably at this level. Higher rates up to 350Amps can be achieved but cables and meters would need upgrading. Battery capacity is reduced by an estimated 25% which increases site losses and some battery heating is evident due to plywood box insulation and state of partial sulphation. Attention should be given to battery maintenance and cell replacement either on an incremental basis as need arises or the complete replacement of all batteries. Improvements can be made to PLC and system controls to automatically handle transient inverter overloads reducing need for site trips in the event of trivial overload faults. I am delighted and indeed honoured to have supplied successful upgrades to one of the SEB's Remote Area Power Systems and look forward to providing this technology and design/consultancy services to Malaysia in the long term. 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