Utilities in the power distribution segment are adopting new technologies to lower their losses, increase revenues, improve power quality, ensure proper energy accounting, enable data-driven decision-making, and deliver better services to consumers. Automation helps discoms provide real-time insights, reduce the operational cost, and foster an efficient and secure working environment.
Some of the technologies being implemented by discoms for providing reliable power are underground cabling, supervisory control and data acquisition system (SCADA) at the sub-transmission level, distribution management system (DMS) or distribution automation (DA) at the 11 kV level and outage management system (OMS) at the 0.4 kV level.
At the sub-transmission level, the grid substation and automation system and SCADA provide centralised control and monitoring of substations. SCADA remotely monitors the power system, facilitates supervisory control of devices and provides decision support tools to improve system performance. Therefore, it reduces the chances of manual errors and eliminates the risk of equipment damage. It also ensures a safe work environment, faster restoration of supply and improved reliability indices like system average interruption duration index, system average interruption frequency index, and customer average interruption duration index.
At the 11 kV distribution level, DMS and DA enable centralised monitoring of the distribution network, and faster identification and restoration of faults. DA consists of a network of digital sensors, controllers and switches, with advanced communication software, which provides increased visibility across the system, and proactively controls and monitors the equipment, load, remote metering, etc. It requires integration with SCADA, OMS, GIS, customer relationship management, business communication management, call centre solutions and smart meters. DMS applications include feeder reconfiguration, fault location invocation, fault isolation and service restoration, load flow application, state estimation, volt/var control, load shedding, load balancing, and load management and loss minimisation. DA drives efficiency, reliability (through reduced outage time), volt-var management (real-time power losses optimisation) and productivity of the utility (lower outage costs), among others.
SCADA helps in the faster identification of faults and early restoration of power through close and continuous monitoring of electrical system parameters on the network. The technology can also aid in strategic placement of capacitor banks and switches, thereby enabling proper planning and design of the distribution network. In addition, discoms that have implemented SCADA have reported better and faster complaint resolution, and improvement in reliability indices and power quality, leading to enhanced customer satisfaction. Moreover, SCADA helps optimise network performance by providing highly reliable information to the management, and ensuring operational flexibility and safety.
Meanwhile, DA helps discoms by providing real-time adjustment to the changing loads, generation, and failure conditions of the distribution system, usually without operator intervention. By observing the voltage and current signals of a feeder line in the distribution substation, the discom is able to identify faults in the system. These signals are also used to identify, locate and classify faults, and based on these observations the faulty line is isolated. Therefore, DA helps automate feeder switching; undertake voltage and equipment health monitoring; and provide outage, voltage and reactive power management. With these features, DA-enabled discoms can provide real-time information to consumers on outages and the average time that will be taken to repair the fault.
Automation leads to operational improvement, which is reflected in the increase in revenue, reduction in the unserved energy, reduction in penalties, delays in capital expenditure, and savings in manpower costs. Some of the measurable benefits of DA achieved by Tata Power in Delhi and central Odisha are a reduction in the number of customers interrupted and customer minutes of interruption by 55 per cent and 53 per cent respectively. SAIFI improvements have been estimated at 17-58 per cent from pre-deployment baselines.
Challenges and the way forward
One of the key issues with the adoption of distribution automation is the generation of large volumes of new data for processing and analysis. It is, therefore, crucial for discoms to formulate policies for data storage, retention, access and security from the start. Also, there are limited standard protocols for data interfaces.
Further, distribution automation requires extensive equipment testing and customisation as automated devices typically need more frequent firmware and software upgrades than traditional utility equipment. This increases the need for workforce training and expertise for field technicians, engineers and grid operators, particularly in database management, data analytics, information systems, cybersecurity, etc.
The communication systems need to be comprehensively planned. SCADA systems are dynamic in nature and require extensive integration and regular updation in GIS. Thus, there is a need to secure proprietary products from vendors.
Going ahead, cybersecurity and interoperability will play a key role in distribution automation. This requires sound cybersecurity policies, plans and practices integrated throughout a project’s life cycle, including design, procurement, installation, commissioning, and maintenance and support.
In the coming years, discoms are expected to adopt newer technologies, apart from SCADA and distribution automation, in order to become smart utilities. Technologies such as smart metering and GIS hold significant potential in optimising distribution operations. n
Based on presentations by Satya Gupta, Director, Tata Power Delhi Distribution Limited and Tata Power Central Odisha Distribution Limited; and Gautam Modi, Deputy Engineer, Uttar Gujarat Vij Company Limited, at a recent Smart Utilities conference