Final Thoughts

The way things are going, it is clear that distributed generation is here to stay. And that is why we need to change the rules.

For most of the last century transmission, distribution and generation were all owned by the electric power utilities. This made it easier to establish rules followed by everybody that ensured that all these components of the system work together supposedly in the most efficient way.
But then at the end of the century things started to change, due to deregulation and the following split of many utilities into transmission, distribution and generation companies. At the same time the so called non-utility generation (NUG) was gaining speed. Rules and standards were developed in order to ensure that safety, reliability and service quality are maintained. One of the key requirements is that NUGs cannot energize an island of the utility power system they are connected to because the utility would not be able to control the quality, safety and integrity of the electrical services delivered to its customers.

Another is the undervoltage and underfrequency protection that is required for each NUG which may result in the tripping of the generators during short circuit faults or wide area disturbances. As a result, when the penetration of DERs is significant the existing rules are in many cases going to make a bad situation worse.

That is why it is important to change some of the rules in light of the continuously increasing number and size of DERs. Changes in the settings of the undervoltage and underfrequency protection, the integration of the DERs in the transmission or distribution energy management systems are some of the most important steps that need to be implemented by the industry.

The concept of Virtual Power Plants (VPP) is probably the way to go, because it allows a single interface from the system level applications with the VPP control system, which is then responsible to control the individual DERs in the most efficient way.

Let?s start with organization in protection testing