1 Implementation of Online ABT monitoring System In The TATA Power Co. Ltd. Mumbai S. G. Patki, S. C. Dhapre, S. G. Joshi, S. A. Wangade
2 Topics Discussed Metering system between TPC & MSETCL. Need for change in metering system. Salient features of online monitoring system. Implementation of online monitoring system. Experience during installation & commissioning. Future needs.
3 Introduction TATA Power Company is the largest private sector utility in India in the field of generation, transmission and distribution of electricity. It owns and operates thermal generating stations at Trombay,Jojobera, and Belgaum with total installed capacity of 1858 MW. It has also set up hydro generating plants at Bhira, Bhivpuri and Khopoli in the Raigad district of Maharashtra with a combined installed capacity of 480 MW. TPC distributes electricity in Mumbai directly and also through its licensees REL and BEST.
4 TPC-MSETCL Interconnection TPC network is interconnected by 220 KV lines to MSETCL at Trombay, Kalwa & Borivli. TPC has provided several 22 KV outlets to MSEDCL from its receiving stations at Kalyan, Ambarnath, Salsette, Kolshet and Panvel. MSETCL wheels power to MSEDCL through 22 KV outlets provided by TPC. TPC also feeds some direct consumers of MSEDCL at Saki and Khopoli. Totally, there are about 24 metering points between MSETCL and TPC, which are spread over a distance of 100 KM. Static HT Trivector meters with TOD features are deployed at above points. Meter data is collected jointly and processed for calculating net interchange between TPC and MSEB used for billing.
Typical TOD Meter
7 Modification in metering scheme In May, 2004, TPC started supplying power to utilities outside Maharashtra, as per availability, using transmission network of MSETCL. ABT tariff was applicable for such transactions and TPC was required to schedule and monitor net interchange with MSETCL on fifteen-minute time slot basis. TOD tariff was still applicable for normal power transactions between TPC and MSETCL. Existing TOD meters were not suitable for this application. It was decided to install new SEMs in series with the existing meters & also provide necessary remote communication system to monitor the net exchange between TPC and MSETCL on a real time basis.
ABT & Revenue meter at MSEDCL point of supply
9 Procurement of ABT meters Salient features included in meter specifications The meter should be compatible with TOD as well as ABT requirements simultaneously. Meter should have two independent auxiliary supplies for better reliability. Meter should be suitable for remote communication on real time basis. Meter should transfer tamper events / abnormalities immediately to server through the same communication port used for on line monitoring.
ABT Meter Procured by TPC
11 Procurement of software Salient features specified for UI Monitoring software. On line monitoring software should collect data from all the connected meters on real time basis and compute net interchange between MSETCL and TPC every minute. Software should provide user-friendly screens for continuous monitoring of net exchange. Monitoring screen should change the color when unscheduled interchange is resulting into net loss to TPC. Events & Communication failures should be annunciated immediately.
12 Procurement of software Salient features specified for UI Monitoring software. It should be possible to prepare daily schedule and e-mail or FAX the same to RLDC. System should generate user defined MIS reports such as monthly UI report highlighting periods of high-unscheduled interchange TPC procured new meters and on line monitoring software in May-2004. The server and Software installation at Trombay,and necessary remote communication set up was completed in November-2004.
ABT meter with online monitoring software
14 The Online monitoring scheme The meter works on serial RS-232 at a baud rate of 1200 bps. The communication protocol is kept proprietary for data security. To get data from connected meters within an interval of maximum 58 seconds, special devices called Net Box (NB-Repeaters) & Data Communication Unit (DCU-Amplifiers) are provided at both ends. Since UI between TPC & MSETCL is calculated by integrating data of all the meters, it was absolutely essential to synchronize their RTCs. A GPS clock is connected to the server, which in turn synchronizes individual meter clocks periodically and ensures time synchronization.
The NET BOX Line Driver & Multiplexer
DCU The Signal Booster
NB DCU Connections
19 Installation & Commissioning Metering points are geographically spread. Out of the total 24 metering points, only 13 were measuring significant interchange of power with MSETCL. 11 metering points were located in consumer premises and their combined consumption was insignificant. A summation meter was installed in TPC substation to record their combined consumption and the same was included in on line monitoring scheme. Getting data at central location on real time basis required very reliable communication network. Dedicated communication network of TPC (MW/FOP) was used for the scheme. Leased lines were used where TPC network was not available
20 Installation & Commissioning Communication configurations were chosen based on availability & reliability. FOP was a preferred media, where available. Out of the 13 major points, connectivity to TPC s own Fiber optic network was available for 8 points located in TPC receiving stations at Salsette, Kalyan, Saki & Kolshet respectively. To optimize the usage of fiber channels, a data bus was formed at Salsette for all the meters connected to FOP network.
Optical Fibre Guard Wire (OPGW on top of the transmission tower)
Fibre Cable Guard Wire Optical Fibre & Guard Wire Separation
Typical Fiber Optic Exchange (FOX)
Typical Fiber Optic Exchange (FOX)
Typical Fiber Optic Exchange (FOX)
Data Bus Formation at Salsette
Data Bus Formation at Salsette
28 Installation & Commissioning Three metering points located at Kalwa and Borivli stations of MSETCL did not have FOP connectivity and required some other media to establish communication with the Server. Leased Telephone Line was used at Kalwa. Combination of Leased telephone line and TPC Fiber network was used at Borivali. FOP network point was available about 2 Km away from the meter. The data is transferred up to FOP point using leased line and further up to Data Acquisition Server ( DAS ) through FOP.
29 Installation & Commissioning TPC Microwave system (Operating frequency 2.4 GHz) was used for two meters at Ambernath as FOP network and leased line were not available. The meter data is transferred directly to DAS through MW system. As some of the metering installations are located in 220kV / 100 kv switchyards, armored, shielded, four pair, CAT-5 cables were used for data communication to avoid electro-magnetic interference. Two meters at Trombay were connected directly to DAS using CAT-5 cables, as they were located close to the server room.
The Microwave Tower
The Microwave Antenna
ABT Meter-1 NB DCU Modem MW MW ABT Meter-2 NB Salsette HUB Ambernath ABT Meter-3 NB DCU FOX - 20 FOX - 20 DCU NBR FOX U SAL Modem GPS ABT Meter-4 Kalyan ABT Meter-5 Saki ABT Meter-6 NB NB NB DCU DCU FOX - 20 FOX - 20 FOX - 20 FOX - 20 NBR NBR FOX U LDD STARS DAS STARS Client Trombay LDD DCU Kolsheth ABT Meter-7 NB DCU FOX - 20 NBR ABT Meter-8 Salsette NB LLM FOX - 20 FOX - 20 NBR LLM Salsette FOP ABT Meter-12 NB ABT Meter-9 LLM DCU LLM Trombay 100kV Borivali ABT Meter-10 NB Kalwa 100kV NBR Leased Line DCU ABT Meter-13 NB Microwave NBR Trombay 220kV Fiber Optic CAT-5 Cable ABT Meter-11 Kalwa 220kV NB ABT Communication Architecture
33 On line monitoring Software Online monitoring scheme works on client-server architecture. The data acquisition server collects & stores data of each meter & the client machine provides online monitoring screens & user-defined reports. Oracle is used for data base management & SQL is used for Server-Client communication on LAN. Meter master data such as Meter Serial number, Meter ID, Multiplication Factor and Installation master data such as Generating station, Virtual meter definition, frequency steps, and UI Rates etc.is configured in Client machine.
Data Acquisition Server
Meter Data on Client Screen
36 On line monitoring Software Software was originally designed for a Generating station and only export scheduling was provided. TPC, being an integrated utility, was required to schedule supply as well as purchase of power and thus needed both import and export scheduling feature. This feature was added later. The software was initially designed to provide only two monitoring screens. UI monitoring screen Graphical screen. Toggle between two screens was inconvenient to our Load dispatch staff. The software was modified and the two screens were merged into a single screen titled Online UI, & graphical screen.
Online UI Screen Last Minute Data
Online Graphical Display
39 On line monitoring Software Merged screen was found very convenient by load dispatcher to monitor real time data such as a) Block time b) Scheduled interchange c) Current interchange d) Average frequency of current interval. e) Interchange since start of block. (Actual Interchange) f) Projected interchange at the end of the block g) Desired interchange to avoid unscheduled interchange h) UI in MW i) Loss or Gain in Rupees j) Alarms.
Online UI & Graphical Display
41 Problems during commissioning During communication trials, it was observed that indigenous RJ-45 & RJ-11 connectors used for terminations on NBs, DCUs & Modems were not getting latched properly resulting into frequent communication failure due to loose contact. Imported connectors were then used to overcome this problem. The data bus formed at Salsette for six meters was intermittently failing to communicate. Investigations revealed that the leased line modems were introducing an extra character in the data string, which was causing CRC failure & pulling the entire data bus down. New MODEM and DCU was put at Borivli to overcome this problem. The leased line at Kalwa was found to be unreliable & communication used to fail frequently. Hence TPC Microwave network was used instead of leased line. Microwave communication was found to be more reliable than the leased line. However, due to external Radio Frequency Interference (RFI), occasional failure was observed on microwave channels also.
42 Conclusion. FOP is found to be the most reliable communication media for such critical schemes. Leased line and Microwave media were not found to be very reliable. When communication with one meter fails, UI report for this period is not available. It should be possible to collect meter data manually and upload the same in the server so that UI report is available for entire month. It should be possible to export interval data and reports in EXCEL format. This will help generate other MIS reports. The billing data, frozen readings, tamper events etc registered by connected meters are not captured by the online integration software. This would be a useful feature. Additional communication channel is necessary to collect load survey data from connected meters. This is unnecessary duplication.
43 Future Needs Of Utility Industry. Power sector in India has a huge investment backlog, but is bridging the gap rapidly due to reforms. Large Business houses like TATA, Reliance, Essar, L & T, Torrent have big investment plans. TATA,s are in fact planning to go global and seeking opportunities in South Africa, Bangladesh, Australia, Latin America etc. These corpoates would need following information on real time basis at their corporate head quarter for smart decisions. 1. Net Generation from each plant,/each unit and Generation cost data. 2. Net sales from each Discom and Genco. 3. Net power purchase / Net power traded 4. Off take /Demands of key customers across the country.
44 Future Needs Of Utility Industry. This will need convergence of IT, communication and Metering technologies. May call for using Internet for meter data collection and transfer. There will be a need for end to end solution providers / service providers. How to cover areas which are remote and lack infrastructure in integrated data management. This will be a challenge. Key concerns will be time, data security, integrity, & system reliability. Can Indian power sector and IEEMA take the bet? Together, we can!
45 Our Contacts Thank you for patient hearing! Please send your queries by E-Mail We will be pleased to respond. scdhapre@tpc.co.in sjoshi@tpc.co.in