Power Angle Measurement

To ensure the power system function safety and stable, it is necessary to observe the whole grids all-around and in real time. In the observing system, no matter the simple observation of the curve,or the establishment of different control scheme, the basic variablerthe power angle is both indispensability .It reflects the state of system most quickly, for its definition comes from the basic reason of the destroy of stabilization: the imbalance of mechanical power and electrical power. In recent years, as the united of different aeras of power grids, the question of power cut in a big area comes , so people put forward higher request for the stabilization of the grid. Now in mass controlling strategy in transient state, the power angle 8 is the basic control variable. So it is the essential premise to acquireδin every time precisely.In this thesis, beside the analysis of the advantage , disadvantage and also the actuality of the two kind ways for measureingδ, there are three parts:(1) This paper validates the meaning of Measurement Demux in the MATLAB which is the scaling module for power angle, concludes the method of phasor graph in the stable-state calculation,fixs the formula and gets the precision of it in the calcuting method of power angle measurement.(2) This paper analyses the two classic methods for calculatingδin the transient state , explains each difficult variable in the resolution formula which is derivated by the Park equation. The core of this chapter is the resolution way for solving ₀ which is the angle between d-axis of rotor and the axes of a phase winding of stator and which can predigest the knot of transient-state power angle calculation. (3)Towards the problem that the equipment can't fix the zero-power angle when starting again after being stopped by some reason, this paper sovles it by adding phasor graph.It can be seen that it is a good way to combining the calculating method and the direct way. This chapter also gives the whole solving flow for transient-state power angle disposal in the direct method, which is realized by the advanced programming tool—LabVIEW.