Dmitrijs Antonovs

Two-terminal out-of-step protection for multi-machine grids using synchronised measurements

To prevent critical power system conditions dedicated out-of-step protection schemes are used in high-voltage networks, otherwise referred to as asynchronous operation protection automation. Structure of out-of-step automation is proposed in this paper addressing angular instability between multiple areas of the grid. Two strategically located substations are equipped with a protection scheme performing synchronized measurement of the local voltage phasors. In addition it calculates four remote phasors in real time and exchanges measurement/simulation results via communication channels. A location for the controllable grid splitting is decided in a flexible manner inclusively addressing influence of highly variable portion of the renewable production. Power utilities currently having limited PMU coverage would benefit from application of the proposed scheme as well as transmission corridors between systems with different PMU usage practices in regards to out-of-step protection.

Out-of-step protection using equal area criterion in time domain

This paper proposes the out-of-step (OOS) protection system, which operation principle is based on combination of two approaches: equal area criterion, implemented in time domain, is used for generators first swing stability assessment and generation sources electromotive forces (emf) vectors angle control is used for multi swing instability detection. The paper focuses on possibilities of practical implementation of the above mentioned approaches within real time operating OOS protection system. Protection system structure and principles of operation addressed in the paper.

Protection scheme against out-of-step condition based on synchronized measurements

The necessity to design special methods and tools for prevention of asynchronous operation is caused by the presence of long transmission lines and structure of the transmission grid of Baltic States and Russia. The method for prevention and elimination of asynchronous operation by means of two automatic devices based on angle control between two simulated voltages is presented in this paper. For voltages simulation GPS and fiber optic communication channels are used. The main problems of devices realization, application and testing are discussed.

Multi-terminal out-of-step protection system

From time to time a sequence of unexpected and often overlapping contingencies may lead to power system angular instability and even blackouts if not addressed adequately by means of an out-of-step protection system. This paper proposes the out-of-step protection system structure, which is based on generation sources electromotive forces vectors angle control. The protection system consists of several strategically located terminals, exchanging information in real time by means of a communication network. Terminals determine online the groups of coherent generators and choose the splitting boundary from a predefined transmission lines cut sets list. The protection system structure, the principles of operation and the possible IEC 61850 communication standard-based implementation are described.

Detection and Management of Large Scale Disturbances in Power System

Recent blackouts of major power systems (PSs) clearly demonstrate the topicality of the blackout problem when rapid multiple tripping of vital PS elements leads not only to PS collapse but also essentially affects the operation of other critical infrastructures. To prevent such situations special types of automation such as PS splitting and frequency control automation are employed. Taking into account the drawbacks of existing devices the new methods and technical solutions to increase sustainability to such events are discussed.

Dynamic Security Assessment and Risk Estimation

In consequence of numerous random and uncertain parameters, the operating condition in the power system constantly changes. Protection technologies, as introduced in the previous chapter, are used to switch of power system devices if a risk of damages occurs. As a result, sometimes system blackouts can take place, which lead to enormous economic, social and environmental losses. The wish to diminish them is only natural. To ensure this task, the concept of risk, which reflects a combination of the probability of failure states and the level of their consequences, is used. To minimize risk, it is possible to use two main approaches: either on probabilistic basis or on deterministic basis. If the probabilistic approach is used for estimating the risk level, it is necessary to know the loss function as well as the distribution laws of numerous influencing parameters. When estimating the risk level, the Monte-Carlo method has to be used.