Increased Automation

MPPTCL adopts advanced technologies to meet transmission targets

Incorporated in 2001, Madhya Pradesh Power Transmission Corporation Limited (MPPTCL) has been an early adopter of new technologies. A pioneer in supervisory control and data acquisition (SCADA) implementation, the company has installed this system for monitoring, operation and control of the transmission system across the state. MPPTCL has also implemented the automatic demand management system (ADMS), one of the most advanced systems in the country. It is also the first state utility to adopt an insulated aerial platform for the hotline maintenance of transmission lines. The transco believes that new technologies are critical to meet its objectives under the “24×7 Power for All” initiative. MPPTCL is also one of the few utilities to adopt new business models such as public-private partnerships.

As of March 2017, MPPTCL’s total transmission network stood at 32,369.39 ckt. km, an increase of 3.2 per cent over 2015-16. The transco has 331 substations, of which nearly three-fourths are at the 132 kV level. Its total substation capacity stood at 53,416 MVA, up by 8.2 per cent over the previous year.

In 2015-16, the transco’s transmission losses stood at 2.88 per cent, marking an increase of 0.06 percentage points over 2.82 per cent in the previous year. Further, its transmission availability was 98.16 per cent, a decline from 99.35 per cent in the previous year.

Key IT initiatives

SCADA

MPPTCL’s SCADA system comprises three control centres, located in Jabalpur, Bhopal and Indore, and is connected to about 330 extra high voltage (EHV) substations. Each control centre acquires data from remote terminal units (RTUs) in its area. The Jabalpur control centre is the central/largest control centre that receives data from the Bhopal and Indore control centres via the inter control centre communications (ICCP) link, which has been established using the optical ground wire network.

In addition, the local data monitoring system (LDMS) installed at each EHV substation has a mini SCADA system. The LDMS also undertakes data acquisition and telecontrol from RTUs via the Ethernet over the IEC 60870-5-104 protocol in EHV substations. EHV substations are equipped with a printer and suitable local SCADA software to view the data and print daily/hourly log sheets.

SCADA implementation has benefited the utility in several ways. These include automatic data logging and generation of reports, effective control and operation of all the EHV substations through real-time information, and sequence of events recording at EHV substations. Further, the system helps in monitoring the quality of equipment such as transformers, circuit breakers, meters and battery sets. It also provides an operational interface for ADMS.

Other benefits of SCADA implementation are reduction in transmission losses by voltage control through centralised information as well as in the operations and maintenance cost of substations, quality monitoring of power supply, and increased equipment lifespan. Further, it has helped the transco to deal with the shortage of manpower as the SCADA system is capable of automatic data logging and generation of all system reports.

ADMS

MPPTCL has also implemented a state-of-the-art ADMS to regulate the overdrawal of power by the state. The ADMS disconnects interruptible loads to protect the grid in overdrawal conditions and then restores them automatically under normal conditions.

Under the ADMS, real-time information is collected through the transmission SCADA system and based on logic developed for the scheme, automatic load disconnection and restoration is carried out. MPPTCL has integrated the ADMS with its SCADA system, which, in turn, is integrated with the state load despatch centre SCADA system via ICCP through which the master control centre at Jabalpur receives data regarding frequency and schedule/drawal.

An interface module for data transfer has been developed between transmission SCADA and ADMS. Based on this data, the ADMS calculates the quantum of load shedding and load restoration for individual discoms as well as for a group of discoms. The ADMS starts functioning whenever grid frequency deviates from its normal range. When the frequency is less than 50 Hz and load overdrawal is more than 12 per cent of  the schedule or 150 MW, whichever is less, continuously for 15 minutes, the shed quantum calculation is triggered in the ADMS. Meanwhile, if the frequency is less than 50.05 Hz or underdrawing of load is less than 12 per cent of the schedule, the normalise quantum calculation is triggered in the ADMS. The ADMS, along with SCADA helps in meeting the automatic demand management requirement through rotational load shedding in all three discoms of Madhya Pradesh through 33 kV feeders at EHV substations.

With the ADMS, the utility has been able to manage loads efficiently. It has also improved grid security and reliability, and reduced the gap in the demand and supply of power.

Maintenance practices

A number of innovative maintenance practices have been undertaken by the utility. MPPTCL has installed an emergency restoration system (ERS), developed by US-based Lindsey, which plays a vital role in the restoration of 400 kV, 220 kV and 132 kV networks. During a breakdown, it helps restore both circuits of double-circuit towers, which in turn restores the supply.

The use of the insulated aerial platform, which is used for conducting and following hotline maintenance operations on the 132 kV, 220 kV and 400 kV single-circuit and double-circuit transmission lines, has been another important initiative.

In addition, the transco has procured winding resistance measurement kits for periodically assessing the winding resistance of transformers. It has been able to save many transformers from failures. MPPTCL has been using high accuracy 10 kV tan delta and capacitance measuring kits to identify issues in the transformer, transformer winding, transformer bushing and current transformers to avoid failures. It has recently procured eight leakage current measurement kits. Besides, numerical differential and distance relays with built-in disturbance and event recorder features are used for feeder bays to analyse faults and restore the operations of breakers.

Future plans

The transco has earmarked a significant capex of Rs 63.73 billion for the next five years (2017-18 to 2021-22) in order to add more than 8,000 ckt. km of transmission line length and 17,000 MVA of substation capacity. The key priority for MPPTCL is to develop infrastructure for the evacuation of renewable energy. Besides developing green energy corridors for upcoming renewable energy plants in the state, the utility is responsible for providing project management consultancy support for the evacuation infrastructure of the upcoming 750 MW Rewa ultra mega solar project. Going forward, with greater renewable integration, the transco will need to undertake more advanced technological solutions to ensure secure grid operations. Given MPPTCL’s pioneering initiatives on the technology front, it is likely to meet this challenge effortlessly.

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