J. E. Daalder

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An adaptive algorithm to prevent undesirable distance protection operations during voltage instability is proposed. The algorithm is based on mathematical logic blocks and uses the rate of change of voltage as an additional relay criteria to increase the relay security with respect to voltage instability. Studies are based on simulations using two different(More)
The aim of this paper is to illustrate that wide area generator speed measurements combined with Fourier analysis can be used to determine coherent generator groups. Studies are based on simulations in a 68-bus test system. Three test cases are investigated where the new method is compared to conventional methods based on the generator speed, modal(More)
This paper demonstrates that appropriate invocation of interruptible loads by the independent system operator (ISO) can aid in relieving transmission congestion in power systems. An auction model is proposed, for an ISO operating in a bilateral contract dominated market, for real-time selection of interruptible load offers while satisfying the congestion(More)
When several utilities operate interconnected power systems, a voltage sag generated in the grid of one utility may affect the loads connected to other utilities. From this point of view, it has become a crucial issue to identify the location of the source of a voltage sag. This paper describes and compares the methods for voltage sag source location. The(More)
This paper introduces a concept of a generator coherency-based System Protection Scheme (SPS), addressing interarea oscillation events. The scheme uses wide-area generator speed measurements combined with discrete Fourier transform (DFT) analysis to determine coherency. A test case simulated in the NPCC 68-bus system is used to introduce the scheme's(More)
The integration of distributed generation (DG) in weak grids can help the utility in providing reliable power to critical and sensitive loads. That requires the modification of the DG controller to be able to continuously supply power to the loads that are connected at the same bus. In this paper, an algorithm has been developed to ensure the continuous and(More)
A shape optimization technique for quasistatic field problems has been developed. The optimization is based on computing the continuum sensitivity function by solving an adjoint problem. We show how this technique can be used to compute, in a very efficient way, the optimal shape of a conducting (or ferromagnetic) shielding structure, in order to minimize(More)
Dynamics of cathode spot has become a major part of vacuum arc discharge with its high academic interest and wide application potential. In this article, using a three-dimensional statistical model, we simulate the distribution of the ignition probability of a new cathode spot occurring in different magnetic pressure on old cathode spot surface and at(More)
The main aim of connecting distributed generation (DG) to the distribution network is to increase the power capacity to meet an increased demand. In case of implementing DGs with a power electronics interface, more functions can be added simply by modifying the control targets. DGs can enhance the voltage reliability by regulating the voltage level at(More)
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