The Smart on-field Meter Accuracy Investigation System for PEA 4.0

Published by

  • Mr.Chitchai Srithapon, Customer Service Division, Provincial Electricity Authority, Email: chichai.sri@pea.co.th
  • Mr.Pichai Thaniwan, Customer Service Division, Provincial Electricity Authority, Email: phichi.tha08@gmail.com
  • Mr.Weerachat Khuleedee, Customer Service Division, Provincial Electricity Authority, Email: weerachat_ee35@hotmail.com
  • Mr.Wacharapong Rakapong, Information System Division, Provincial Electricity Authority, Email: nidpea@gmail.com

Published in PEACON & INNOVATION 2018 “PEA4.0 : Road to Digital Utility” 24th– 25th September, 2018. Centra Government Complex Hotel & Convention Centre Chaeng Watthana Chaeng Watthana, Bangkok

Abstract

According to the service standard policy by the Energy Regulatory Commission (ERC) of Thailand in 2016, made all of electricity utilities have to verify meter accuracy of all residential customer meter to make sure all meters measure reading is precision in accuracy class of 2.5% for every 3 years. Today, Provincial Electricity Authority (PEA) has the existing residential customer kWh meters about 17 million, where it required many work task and high budgets to achieve this mission. Therefore, PEA team had developed the on field meter accuracy testing system to be able to perform operating faster and make a cost saving.

The proposed smart system was designed to complete with a new meter tester feature and new software implementation on both internet web service and smart phone application. The implementation of this mobile workforce has showed that the meter accuracy investigation in field site capacity per day increased by 67.6% and could save testing investigation cost about 38.9% when compare with the traditional method.

Key words: Innovative, kWh meter accuracy, mobile workforce.

1. Introduction

Currently, the electrical industry structure in Thailand is the enhanced single buyer model, the Electricity Generating Authority of Thailand (EGAT) is a producer of electricity for power transmission and is the sole purchaser of electricity from private power plants and buys electricity from abroad, then will distribute electricity through the transmission system to the Provincial Electricity Authority (PEA) and Metropolitan Electricity Authority (MEA). By the Energy Regulatory Commission (ERC) of Thailand is responsible for overseeing the overall electricity tariff structure.

PEA who is the biggest power utility in Thailand, supervise power distribution and electricity energy retail system for most provinces areas of Thailand, except only for Bangkok metropolis, Nonthaburi and Samutprakarn province that responsible by the MEA. PEA is the state owned enterprise of Thailand, which is the owners of the power transmission lines, power substation, distribution system, mini hydro power plant and kWh meters. The description of PEA importance data is show in Table 1.

Table 1. PEA Importance data [1]

DescriptionData
Power line (circuit-km)
H.V. Transmission Line 12,258
M.V. Distribution Line 308,958
L.V. Distribution Line462,786
Number of power substation544
Number of Customers19.35 million
Total Sales of Electricity (kWh)132,399 million
Total Assets (Baht)398,305 million
Year revenue (Baht)463,747 million

According to the service standard policy by the Energy Regulatory Commission (ERC) of Thailand in 2016 [2], made all of electricity utilities have to verify accuracy of all residential customer meters to make sure its reading accuracy is in class 2.5% for every 3 years. Today, PEA has the existing residential customer meters about 17 million meters and most of them are electromechanical meter type. The number of new meter in first 3 years installing that was verified accuracy by factory test has about 3 million and the installed meter with more 15 years old that will be planned to replace by new meter has about 2 million per year. That means the number of meter that PEA have to verify meter accuracy under ERC policy about 4 million meters per year. The operation cost of meter accuracy testing separate by operating method is shown in Table 2. The operation cost of meter accuracy testing in laboratory is about 540 million THB per year and for on field meter testing about 240 million THB per year. Therefore, it is reasonable to do meter accuracy testing job in the field site.

Table 2. Operation cost of meter accuracy testing by method

MethodLaboratory TestOn Field Test
Number of meters testing per year4,000,0004,000,000
Testing cost/meter135 THB60 THB
Total cost/year540 million THB240 million THB

In this paper, we first describe the on-field meter accuracy testing methodology in Section 2. In Section 3, the new system implementation result is presented. In Section 4, the paper is briefly concluded.

2. On-Field Meter Accuracy Testing Methodology

The traditional methodology of on field meter accuracy investigating for residential customer meter in PEA is worked with a standard clamp on meter and testing results was recorded in hard paper form [3],[4]. In the case of a customer kWh meter no load current that mean no any energy reading in that time, to can do a meter accuracy testing it need to unplug the power cord in customer load side and reconnect with the dummy load such as a light bulb or a heater coil. That it made this method has a long time for meter testing and may interrupt electricity usage of customer. The working capacity for on field meter testing by the traditional method is about 30 meter per day, where it was required many technician staff and high budgets to achieve this mission. Therefore, PEA team has proposed the new system for on field meter accuracy investigation that can be able to perform operating faster and benefit to the operation cost saving.

The smart on-field meter accuracy investigation system was developed to be able perform faster on field meter testing and to keep the testing results in to digital file (paperless), that could be saved much more operation cost in this work. This smart system is designed to complete with an innovative meter tester and the new software applications on both internet webpage service and the smart mobile phone application. The diagram of the smart on field meter accuracy investigating system for PEA 4.0 is shown in Figure 1.

Figure 1. The diagram of smart on field meter accuracy investigation system for PEA 4.0

2.1. The Innovative Meter Tester

This innovative meter tester is named as “GDL”, it was designed for 1P2W meter testing. It was completed with an internal current source, to make the kWh meter reading (rotating) in case of no customer demand current. This smart meter tester was calibrated with standard meter tester (accuracy class 0.1%) at instrument calibration laboratoy in Meter division, PEA and had passed accuracy qualification in class 0.5%. GDL also was built in the Bluetooth communication module to sent the testing result to a smart mobile phone. This smart tester also can be used to measure the electricity consumption parameters such as voltage, load current and demand power in during meter testing. After completed testing, it will be displayed the testing result on its LCD display monitor and sent the testing data to a smart mobile phone or smart mobile tablet. The system diagram of GDL is shown in Figure 2.

Figure 2. The system diagram of GDL

The meter tester will measure the voltage and currents waveform from kWh meter under testing through the ADE7953 IC chip [5]. This IC chip is use to measure power and energy parameter and the example of active energy error reading as a percentage by this IC chip is shown in Figure 3. The accuracy testing by this method is to compare the energy measurement between the GDL reading and a kWh meter reading in the same period testing.

Figure 3. Current Channel B Active Energy Error as a Percentage of Reading (Temperature = 25°C) over Power Factor with Internal Reference, Integrator On

The error as a percentage calculation of a kWh meter accuracy testing is derived by equation (1) and (2).

Where:

  • % error is the accuracy of kWh meter under tested.
  • Whmeter is energy (Watt-hour) reading from meter.
  • WhGDL is energy (Watt-hour) measure by GDL tester.
  • GDLerror is %error offset of GDL form calibration laboratory.
  • Ncycle is the number of testing cycle.
  • Revmeter is constant value of kWh meter reading.

2.2. Software Applications Development

This smart system is operated via online system with software applications that used to interface with the PEA smart customer service system (SCS). The software applications were developed on both internet webpage service and smart mobile phone application. The webpage application use for on field kWh meter testing in job planning, generate working order, testing result recording and test data reporting.

The example of internet webpage application is shown in Figure 4.

Figure 4. The example of webpage application for on field meter investigating system

The mobile application was design to use in field site that can be download meter information from the PEA-SCS system such as customer name, supplier and installation date etc. A smart phone can be communicated with GDL by Bluetooth signal to receive the test result and then record data in mobile memory. Ones it has internet signal maybe from Wi-Fi system or GSM signal, it will can be uploaded the testing data into database server. This application also has the meter locator finding function by interface with the data from PEA Geographical Information System (PEA-GIS) where keep the x-y location of the customer meter and can be sent back the current meter location into the GIS database. The example of mobile application for this smart on field meter accuracy investigating system is shown in Figure 5.

Figure 5. The example of mobile application for the smart on field meter investigation system

3. System Implementation

The smart on-field meter accuracy investigation system has deployed in Northeastern regional of PEA since August 2017. The example of system implementation in the field site is shown in Figure 6.

Figure 6. The example of new system implementation in field site

The data of meter accuracy testing result by 4 months system implemented with 140,000 meters sample data is shown in Table 3. The result is shown the new innovative meter tester can be detected the failed kWh meter that reading accuracy out of class 2.5% in distribution network. By the failures rate is about 0.46% which those failed meter were confirmed testing in PEA meter testing laboratory with a same result.

Table 3. On field meter accuracy investigating data


The result of working performance based on number of on field meter testing capacity per day is shown in Table 4. Data shows the new smart system for on field meter accuracy investigating can be tested accuracy about 50 meters per day, while in the traditional system can be done about 30 meters per day. That means this new smart system developing can be performed operating performance improvement about 67.6% when compare with the traditional system.

Table 4. On field meter testing capacity


For the operation cost comparison between the new propose system and the traditional system is shown the operation cost by new system is lower than the traditional method about 38.9%. Where it can be saved the PEA operation cost budgets for on field meter accuracy testing for 4 million meters in yearly target about 210 million THB.

4. Conclusion

This mobile workforce system for on field meter accuracy investigating in PEA, that consist of the innovative meter tester and the new software applications on both internet webpage service and a smart phone application. The innovative meter tester was designed for 1P2W meter testing, which completed with an internal current source for testing a kWh meter in case of no customer load current. The new software application is used for job planning, working order generated and testing reporting. The developed smart phone application can be communicated with the meter tester by Bluetooth signal to receive the testing result. And then it will be uploaded the testing data to the PEA database server by internet protocol.

The new system implementation has been shown the on field meter accuracy testing working efficiency improvement, by increase the on field meter testing capacity per day about 67.6% and can be saved the operation cost about 38.9% when compare with the
traditional methodology. The other advantages of this new smart system is benefited for distribution system improvement such as the voltage from meter testing can be used to monitor voltage quality in network area. The mobile phone position (x-y) in a same position of tested meter will be used to correct a meter location in PEA’s Geography Information System (PEA-GIS) and the meter accuracy testing data also keep in digital database server that it is very useful for another data analytic application in the future.

Acknowledgment

The author would like to thank the support team for this project implementation in Northeastern regional. And this the innovative meter tester development was supported by Provincial Electricity Authority innovative funds in 2017.

References

[1] Provincial Electricity Authority (PEA), “PEA Annual report 2017”, Bangkok, Thailand, 2018,
[2] Energy Regulatory Commission (ERC), Thailand, “Power Purchase Agreement (Small power users) in accordance with the standard of electrical service contracts, 2017”, pages 11-13., 2017.
[3] Provincial Electricity Authority (PEA), “PEA Regulations on Meter Metrology Practices,” pages 89-90, 2015.
[4] Provincial Electricity Authority (PEA), “Electrical Equipment Specification No: RTES-136/2539, a class 0.5 standardized meter, is available for single phase test “, page 4, 1996.
[5] ANALOG DEVICE, “ADE7953 Data Sheet,” MA, USA, 2011.

Published by PQTBlog

Electrical Engineer

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