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IET promoted: DPSP 2020 conference - challenges for power system protection

Technological changes, including the rise of renewables and the shift from mechanical to digital, are creating new challenges for the power system protection industry.

Richard Adams, Principal Engineer at Ramboll and Chair of the Developments in Power System Protection (DPSP) conference, discusses new technologies, the challenges around them and how they’re affecting protection engineers.

What impact are renewables having on the power system protection industry?

As we move away from traditional fossil fuels to more renewables, it’s reducing system inertia and the fault current levels we get on the system. It’s going to continue to do this because the newer generation types are connected by electronics, rather than the large synchronous generators we’ve been used to.

Traditionally, we’ve relied on very high fault current levels to be able to detect a fault. But with decreasing levels, the feeling is that it’s going to become more difficult, or may be impossible, to differentiate between actual load conditions and fault conditions.

Has industry found a solution to decreasing fault current levels?

Some people think that these new converter-based short sources should be configured so that under fault conditions they provide more current, acting in a similar way to traditional synchronous generation.  Others argue that we shouldn’t be doing this because high currents stress equipment, and we should really find new ways of detecting fault conditions.

One way we can do this is by travelling waves, which have been used for many years for fault location, but not very much for detecting and isolating faults. Rather than fault current, they rely on the voltage and the characteristics of the circuit for fault detection. We may need to come up with other methods as well.

What about other greener technologies like electric vehicles? Are they having an impact on power system protection?

There is talk of electric vehicles being used as a source of supply under emergency conditions. So because they’ve got batteries, if the network needed it, you could actually draw electricity from these batteries for a short period to meet the demand. That’s going to mean that the power is then flowing from the vehicle back into the network.

Traditionally, the distribution networks have been configured only to draw power and not to provide power, so that could affect some directional protections and it may mean that networks need to have protection modifications.

So I think there are some challenges ahead and it remains to be seen exactly the extent of those challenges and how the infrastructure needs to be modified.

 What affect has the ‘digital revolution’ had on the industry?

Modern relays are digital by design and provide a lot more opportunity for integration and more protection functions than the older electrical mechanical relays ever did. In the past, there would be one relay per function, whereas now you can have a whole host of functions within one relay.

The integration of functions reduces cost and the space required in the substations, which means we can reduce the size of buildings and land required. The flip side is that modern relays have a shorter life span than the older relays.

Do the modern relays create any challenges?

Modern relays contain a lot of functions, but there may be some which you don’t want to use. It’s important that we make sure that they are turned off and that they’re not going to cause any problems in service.

Also, the modern equipment has either ethernet, USB or wireless access connectivity. This could be very useful for upgrading the functionality or settings and remote access, but it creates a vulnerability, a little gateway into the substation, which some people could exploit.

In theory you could have someone sitting in a vehicle outside of a substation, trying to hack into the control system or relays from just a few metres away, without physically going in and doing anything.

How is industry responding to the complexity of modern relays?

A lot of utilities remain very conservative, understandably due to the implications of lost supply. I don’t think wireless access will be used for some time yet, unless there are a lot of guarantees in terms of security.

I think the future protection engineer is going to need to know a lot more about control, communications and cyber security because it’s very difficult to separate them now. What might have been handled by a number of different departments in years gone by is becoming one department with multiskilled engineers.

 

Richard Adams is chair of DPSP 2020, taking place in Liverpool on 9th -12th March 2020

We are accepting abstracts for the conference programme until Monday 29th July 2019

Find out more by clicking this link theiet.org/dpsp 

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