Next Generation Technologies for Substation

Power experts and technology providers; discuss opportunities, challenges and the available advanced and modern technologies in place to address the digital requirement in the industry.

With the rapid expansion of distribution generation technology and increasing power demand, the industry has been striving to introduce and implement various solutions to aid the power and utility providers in India. It includes technological additions for efficient and enhanced operations at power substations. Adoption of IoT and other digital technologies is expected to address the call for cost-competencies, high-efficiency, and reliability in the integrated substation.

Distributed generation impacting the power quality

Prabhakaran PV, Head – Product Management, Fluke India – Earlier in the past, we had only one centralised generation that is mainly a thermal power plant or a hydro power plant, which is then transmitted and distributed through the long lines. Today, the process is changing with the concept of smart grid with the new buzzword ‘Prosumers’ in every industry. Prosumers basically means producer cum consumers, where every large industry is producing power for their own consumption and export unused power to the grid. Interestingly, the new generation green technology generation systems are non-conventional and it use high power electronics in it.  So, you have to make your systems more reliable, more redundant, and that is where you need to focus on and similarly this power quality issues or any of those issues, which can also impact the new generation small systems that also can create a reliability issue in your system.

Assuring power quality for producers and consumers

Head of Department, Technical Services, Tata Power Delhi Distribution Ltd.- At TPDDL, we have around 40 megawatts of solar capacity installed on consumer premises, and since these are connected to our distribution network, I guess already rightly pointed out that the term that would be used for this type of customer is a prosumer, which is basically a producer as well as a consumer. From a utility perspective, there are two key challenges: power quality and predicting power demand. As of now, the TPDDL has a demand of around 2000 MW. This 30 MW or 40 MW is not causing much trouble for us, but once it reaches a level of 400-500 megawatts, then predicting the demand for the next day will be difficult.

Secondly, power scheduling demand forecasting is one big challenge that our utility faces if you have a large base of prosumers and installed consumers. Another interesting space is the P2P trading platform. We at Tata Power are doing one pilot with NextCharge, an Australian start-up, wherein we are experimenting with blockchain technology where prosumers can directly trade on the p2p platforms. So, decentralisation and DRMS are going to be the future technology and the utilities have to prepare themselves basically on two aspects: one is power quality and the second is demand forecasting.

Architectural changes in the existing substations for digital upgradation

Sandip Maity, AVP, Design and Head-Substation Engineering, Sterlite PowerTransmission Limited. – If you have a brownfield substation, along with the advantage of modern technology, then why not to upgrade them as per the innovative standards of the new ones. Here, instead of taking entire substation to shut down there that take one by one day, and then replacing those copper cable with the margin units, and from margin units if we take up those signals to the fibre-optic cable; obviously the old relays may not be suitable for this purpose to analyse the optical data point. So, probably by taking one way shutdown making it live then going to the next day. That’s how we can improve the Brownfield substation with the present technology availability.

Upgrading old generation equipment for better communication through IoT

TPDDL started automation way back in 2005. Every OEM has got their own protocols, and in some cases, the RTA is basically a data concentrator unit for a substation. So, some of the IDs are for communication. We have to have a dedicated RTU to make particular IDs.

When we talk about digital substations, interoperability is one of the key aspects. The equipment needs to be on IEC-61850. We have made required changes in our specification and also all the equipment’ we are purchasing not from now, even form seven and eight years – all of those are IEC 6.850. So, like they are compliant for new this technology for digital substation. Already we have what this concept of the station bus but we are not having a process bus. So, necessarily like for upgradation to the future technology, all your specification and all your procurement, should also be ready for the next generation technology.

Challenges in implementing security policies in digital substation

When you have the distributed systems, cybersecurity is much more secured when it comes to the distributor system. “When you have a single centralised system anyone can intrude into one system lead the entire nation towards a crisis situation. Today, all these distributed systems or the distributed generation facilities have a term called islanding system, where it can isolate itself from the main grid, and can have its own centralised control systems,” Prabhakaran elucidates. This control system is placed away from the major networks which further protect the distribution system or any generation plants from any intrusion. So, when it comes to distributed networks, we have better reliability.

Continuing the discussion further, Sandip explains, “We do have changes in terms of implementing security requirements as we have a lot of security changes and security checks in place, and some guidelines were issued by the CEA in 2020 where they suggested standard security systems and firewalls for hardware and software, and zoning of the networks.” With this multi level protection, in addition to the security and password policy that every organisation is quite proven as it can prevent any attacks in the power systems.

Effects of digital substations on power quality and tariffs

No, digital substations will not have any direct impact on the tariff, but it will definitely hit the CAPEX. If we compare it to conventional hardware technology, it is going to be costly. In order to make a CAPEX expansion, we have to get regulatory approval. In our case, the DRC is associated with a regulatory approver, and even though they have certain cost data, there is a certain ceiling which has been defined by the regulator, “explains Yogesh. There won’t be any direct impacts on the power tariff, but in certain cases there are challenges related to the infusion of the CAPEX and obtaining the regulatory approval.

Enabling seamless power distribution for smart cities

Here, when we have a smart city in place and are implemented with its entire component, this technology, like IoT, information is exchanged on a real-time basis, and any kind of change in the load requirement will be reflected. “Obviously, there are complications, but kind of probability and facility available today, and with the technology advancements, I am sure that few years down the line when smart cities will be fully operational, technologies will attempt to sync the requirements for better and smooth experience” shares Sandip.

Power concerns or crises will be completely addressed by smart substations.

From the quality perspective, we have challenges towards voltage profile parameter; the second one is your frequency. So, there were issues related to the voltage sagging, because like there was more of a reactive power and like there were more or less of a capacitor installed at the grid substation. Voltage sag was an issue in 2000 but today, our challenge from a utility perspective to the power quality is the voltage swelling. We are proposing is, rather than installing the capacitors, we have to install the reactors at our KV level. “We have to recalibrate our strategy to ensure quality things to it then again like within if you look at the regulation, because even the policy part is a very great lever just to have a penetration of the technologies and these aspects of the quality”, highlights Yogesh.

Whereas, Sandip feel that his is a requirement for the Make in India campaign as we have a lot of smart substations. Maybe those are at 33 KV or level three voltage levels that can meet the basic requirement. But quality power would be a concern, so from the grid level, distribution network, and transmission network, we must take care of the PQ parameters that will allow us to avert voltage sagging and improve production in the factories that require quality power to commence their activities.

Implementation of IoT and digital maintenance practises to improve distribution and utility efficiency

It’s not a mandate to disrupt the existing system while implementing and adopting the newer technologies. But the point here is about having the flexibility and availability of technology that you having the flexibility and the technology available and based on your plan of the subject. Explaining it even further, Sapdip adds, “Suppose you have 30 or 40 substation; let’s take the one which is not that crucial from distribution point of view and implement all these techniques on them and get to that, and how you are getting benefit out of that  and then moving on to the gradual next substation.” If we take up one by one, so basically we’ll be getting the personal advantage of it, and it will give a confidence to the operator. Yes, this technique is helping me to decide my operation to plan my CapEx and OpEx. And gradually they can build on and becomes a practise for that operator. So my session will be taken that way, rather than jumping holes page together in all substations.

Optimism for consumers on brownfield substations

If it is the modernisation, then yes, this enhances the system’s performance and assurance. This means you are going to reduce the amount of maintenance or amount of expenses you’re going to incur and increase its reliability. With this, you’re going to save on the cost of the maintenance, and attain better service from the same equipment. You will further reap benefits on the return on investment very quickly. That way, you are expanding its lifespan and you are also gaining the serviceability of the system itself. That is an assurance because you can’t give it in any of the ways. You cannot show them that, okay, exactly this much amount you will be saving. “But these are just some of the tangible and intangible benefits that they’re going to gain. And that’s why technology is always an enabler. And that needs to be understood in the holistic sense”,  Prabhakaran concludes.