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Enhancing DMS Software to Secure Electric Power Network Service

Researchers: Marija Ilic, Ozan Tonguz

Abstract

Enhancing DMS Software to Secure Electric Power Network Service

Project background - During the first year of this project this team has:

  • Pursued simulations of the Oakland distribution feeder in collaboration with the local utility. Real data have been gathered, and organized in the data format required by the Distribution Management System (DMS) software given to our team for research and education purposes by the DMS, Inc. Marija Prica and Eugene Toh have been instrumental in carrying out this very difficult task.
  • Our graduate student Zhang Yi has worked with Professors Marija Ilic and Ozan Tonguz on identifying typical problems with automated protection systems of today. The blackout problems are viewed as a particular case of what may be a much harder scenario under intended attacks.

Our proposal for this year is to grow the effort and support both Zhang Yi and Marija Prica under this effort. Minghong Toh has his own support, and will be active participant in the research.

The following objectives are proposed for this project:

Task 1: Enhancing DMS software to include responses of the power users in order to ensure minimal service even under intended attacks:

Further use of DMS-based simulations will be pursued for understanding the role of load control in ensuring secure response during unusually difficult conditions (caused by either equipment failures, and/or intended attacks). The concept is to make the end users active respondents   and to show that a typical blackout situation can be prevented through an approach of this type. It is needed here to work closely with the DMS, Inc to enhance the existing software to allow for this flexibility.

The basic concept is that the top-down scheduling by a system operator is insufficient during attacks, and the system will be put in place to demonstrate how to save the essential service. Distribution Management Software (DMS) is commercial software developed by Science and Technology Park of University of Novi Sad, Serbia and Montenegro.  The development of the DMS software was motivated by the need for efficient distribution management.  Regulated and deregulated distribution companies face challenges in the management of distribution networks, of which DMD could be a solution to automation in the industry.

Task 2: Enhancing secure electric power network service by smarter protection schemes

This research task draws upon the fields of simulation, networking, and distributed computing to identify inherent problems and potential solutions in using Internet technology in real-time environments with a particular focus on the electric power grid. The task is motivated by our recognition that today’s protection of equipment in electric power systems is local (i.e. without any communications), except in the case of special protection schemes. It was recently proposed in a doctoral thesis of Ken Hopkinson form Cornell University that this situation can be greatly improved through communications means.

Our team already has simple conceptual counter-examples which show that it is not sufficient for relays to only communicate to each other in order to have secure protection of the system as a whole. Our premise is that it is essential to combine communications with careful local logic of each relay. This logic must rest on fundamental engineering laws.

It is the objective of this research task to further pursue this premise, and design powerful protection schemes which both communicate  and are smarter than today’s relays. It has been well-known that several blackouts have been directly or indirectly caused by malfunctioning relays.  In situations, like intended planned attacks, these problems will become even more pronounced.

The second part of this task concerns the best choice of communications in support of smart protection. Many believe that Internet might be sufficient for this purpose. However, the use of TCP logic is not likely to be effective support. TCP due to its transmission guarantees and widespread use in the Internet is popular, but the TCP was never designed for use in applications that have time dependencies and it has many undesirable properties that make its deployment problematic in those situations.

In this project several alternatives will be explored, such as Stream Control Transmission Protocol (SCTP) and UDP.  SCTP is

  • Similar to TCP in many ways.
  • Connection-based protocol.
  • Uses the same Additive Increase Multiplicative decrease congestion control mechanism. It adds a number of additional features that make it more adaptive to applications with real-time requirements than TCP.
  • Allows transmit information out of the FIFO order
  • Allows users to establish multiple transmission streams.
  • Can be multi-homed.
  • SCTP is not being considered in the upcoming IEC 61850 standard, but the protocol may receive increased attention in the future.

UDP, on the other hand has the following features:

  • Makes a best-effort attempt to deliver a message
  • Message delivery is not guaranteed.
  • The initial backup protection communication investigations use the UDP protocol for its nearly universal support and low latency despite its lack of delivery guarantees.

Another possibility is GOSSIP. Gossip-based communication protocols, also known as epidemic or probabilistic protocols, are attractive in cases where absolute delivery guarantees are not required due to their scalability, low overhead, and probabilistically high reliability.

The traditional information arrangements offer the following characteristics:

  • All nodes in a system belong to the same process group
  • Nodes choose others to send gossip messages to using a uniform probability distribution.

The newer options to explore are characterized as:

  • Nodes in a process group are broken down into subgroups.
  • Each subgroup is associated with a rating r?[0,1] that corresponds to the target rate for information updates.
  • A higher rate will yield more information.

Finally, this task will explore the most appropriate communications medium for implementing smart flexible protection system capable of being much more adaptive to the difficult environments. The choices   for communications media will be twisted-pair, coaxial, fiber optic, wireless and power transmission lines themselves.

Main project deliverables:

Our goal is to demonstrate secure electric power grids in which the power users and smart protection play the main role. This is a qualitatively different approach from relying on centralized scheduling of power generation, entirely passive demand and non-adaptive protection. The concepts will be illustrated using Oakland network and real life data. The DMS package will be enhanced to add active decision making by the consumers, new protection logic and communications among the protection devices. Several test cases will be produced to compare the superior performance of the envisioned schemes during intended attacks.