Since all columns include only zeroes, all state variables are observable.Numerical tests carried out using the IEEE Reliability Test System [8], including voltage, active and reactive power injection, and active and reactive power flow measurements, show the effective behavior of the proposed algorithm. IV. CONCLUSIONThis letter proposes and illustrates a novel technique to state estimation observability analysis. This technique relies on computing the null space of the Jacobian measurement matrix. The computational burden involved is, therefore, that pertaining to the null space calculation, which is similar to the burden of solving a linear homogeneous system (O(N 3 )). A simple example is used to demonstrate the efficacious functioning of the technique. Extensive computational analysis involving voltage and active and reactive power measurements as well as current measurements is the subject of a future paper. App. Syst., vol. 100, no. 2, pp. 691-698, Feb. 1981. [6] , "An orthogonal row processing algorithm for power system sequential state estimation," IEEE Trans. Power App. Syst., vol. 100, no. 8, pp. 3791-3800, Aug. 1981. [7] REFERENCES I. INTRODUCTIONIncreasing interconnection of power plants in modern large electric power systems has made power system dynamic studies much more complex. Under the deregulated business environment, the interconnections are increasingly being used for trading between utilities. This stresses the interconnections through large power transfer. As a result, the system is prone to low-frequency interarea oscillations. In such an operating scenario, the system behaves coherently with groups of coherent generators separated from other groups of coherent generators linked through weak interconnections.The analysis of an interconnected power system is generally for a specified portion, called the study system, while the rest is the external portion of the system approximated to its equivalent of lower dimension. Since the impacts of major disturbances propagate through tie lines to neighboring systems, it is important to represent not only the power system in question but also the neighboring utilities or the external system in terms of its dynamic equivalent.Coherency-based approaches to dynamic equivalents have been adopted in reducing the size of the power system model [1]- [3]. However, coherency was identified with the help of the linearized model of the power systems. More often than not, the access to system dynamic data involving a number of utilities is incredibly difficult. The accuracy of the system model influences the accuracy of the results. Also, owing to the dimension of the interconnected systems, it is neither easy nor desirable to represent the entire system model in detail.In this letter, coherency is obtained from measured data, obviating the need for detailed modeling information. The method is based on principal component analysis (PCA), which is computationally simple and fast. An industrial application of this method will take the wide area measur...

The application of loop shaping in H N control design through a dual-input power system stabiliser (PSS) in a benchmark power system model is demonstrated. The PSS stabilises two key system poles contributing to critical electromechanical oscillations involving turbine generators and electrical network. The IEEE First Benchmark Model has been considered in this study to demonstrate the effectiveness of the control. A linearised model of the system is pre-and post-compensated using loop-shaping approach. The problem of robust stabilisation of a normalised coprime factor plant description is formulated into a generalised H N problem and the solution is obtained analytically. The performance of the controller shows robustness to electromechanical modes, which were otherwise very poorly damped or undamped depending on operating conditions. The robustness is further validated in Simulink, including nonlinearities and device saturation limits.

The paper investigates the impact of large scale wind penetration on the inter-area mode damping of a power system. Simulation results using a two-area test system and a representative GB test system are used for the study. Different possible operating scenarios of the systems are generated and a qualitative behavior of the impact is presented.

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Abstruct-This paper illustrates the application of GloverMcFarlane's H , loopshaping technique to design a dud-input Power System Stabilizer (PSS). The PSS stabilizes one key subsynchronous (SSR) mode and a local mode contributing to critical electromechanical oscillations involving turbine-generators and electrical network. The IEEE First Benchmark Model (FBM) for the analysis of SSR phenomena has been consided in this study. A linearized model of the system i s pre-and post-compensated using Iwp-shaping approach. The problem of robust stabilization of a normalized coprime factor plant description is formulated into a generalized H, problem and the solution is obtained analytically. Stability of the system is discussed through eigenvalue analysis. The controller has ensured good damping to subsynchronous modes which were otherwise very poorly damped or undamped depending upon operating conditions. I d e x Terms-subsynchronous resonance, fixed compensation, eigenvalue analysis, H,, control, loop shaping