Reactive Power Balance Research Articles

Development of a knowledge‐based system for voltage/reactive power operation planning

AbstractVoltage/reactive power planning is a tremendous process which requires a planner to have intellectual expertise. This paper presents a large knowledge‐based system that can make voltage/reactive power planning. The knowledge acquisition has been completed on the basis of interview and protocol analysis methods. The result shows that the voltage/reactive power planning is composed of three phases: the first is reactive power adjustment where overall reactive power balance is investigated; the second is voltage adjustment where all bus voltages are tuned within the permissible operational range; and the third is voltage adjustment with a single fault of all major lines. The knowledge base is coded by about 700 production rules. It can succeed in making a voltage/reactive power plan for a very large power system.

電圧/無効電力調整計画のための知識ベースシステムの開発

Voltage/reactive power planning is a tremendous process which requires a planner to have intellectual expertise. This paper presents a large knowledge-based system that can make voltage/reactive power planning. The knowledge acquisition has been completed on the basis of interview and protocol analysis methods. The result shows that the voltage/reactive power planning is composed of three phases: the first is reactive power adjustment where overall reactive power balance is investigated; the second is voltage adjustment where all bus voltages are tuned within the permissible operational range; and the third is voltage adjustment with a single fault of all major lines. The knowledge base is coded by about 700 production rules. It can succeed in making a voltage/reactive power plan for a very large power system.

Stabilizing control for overvoltages in a separated power system with heavy load and large shunt capacitance

This paper deals with overvoltages caused by self-excitation in a separated power system, which has some generators, heavy load and large shunt capacitance of underground cables and/or shunt capacitors. The condition of voltage stability in a separated power system is analysed in the G-B c (admittance) plane. Even when the system is stable, there is a possibility that the voltage is too high or too low, or the frequency is not in the desired range. These phenomena are also analysed in the G-B c plane. In stabilizing the separated system, it is necessary to consider not only the active power balance, but also the reactive power balance. Stabilizing control strategy for the separated system is proposed based on the analysis in the G-B c plane, and the simulation results of the stabilizing control strategy are presented.

Insecure System Reactive Power Balance Analysis and Counter Measures

Insecure System Reactive Power Balance Analysis and Counter Measures

Insecure System Reactive Power Balance Analysis and Counter Measures

One of the consequences of a calamitous system disturbance can be a mismatch of a system's reactive power demand and its reactive power resources. Power system collapses have occurred for both situations-when there has been a reactive power deficit and a reactive power surplus.

Advanced Scheme for AC Voltage Control at HVDC Converter Terminals

A new economic and effective scheme for controlling the ac voltage at the HVDC terminals during both steady state and dynamic conditions is presented. By extending the basic characteristics of an HVDC converter, it is possible to affect and modulate the reactive power balance on the ac side. Analytical studies as well as digital and simulator results are presented to demonstrate the viability of the proposed ac voltage control strategy to optimize HVDC terminal design and performance for a practical system. The economic and technical features of the new scheme are discussed and compared with other ac voltage control techniques such as synchrononous condensers and static VAr compensators.

Voltage Stability Analysis in Electric Power Systems by Nonlinear Programming

ABSTRACT Voltage instability phenomena in electric power systems are characterized by a progressive lowering of receiving end voltages beyond their nominal values.Particularly, a voltage collapse occurs at a load node when the active power fed from the load reaches a maximum value. On the basis of this observation a new method for the analysis of the voltage stability in power systems is presented.The suggested approach derives the critical voltage stability conditions for the system through the solution, by non linear programming techniques, of a non linear constrained optimization problem which considers as objective function the active power demand at a prefixed load node and as constraints the active and reactive power balance equations at the system nodes and the practical operating capabilities of generators. The method proves suitable for a rigorous individualization of the factors which affect voltage instability phenomena and can advantageously be used for planning and operation of electric power...

サイクロコンバータを用いた無効電力補償装置の無効電力平衡に着目した動作解析と補償限界

サイクロコンバータを用いた無効電力補償装置の無効電力平衡に着目した動作解析と補償限界

On the changes in the fundamental component caused by the higher harmonic components in an oscillator with resistive nonlinearity

In an oscillator with nearly sinusoidal voltage, the change ΔI 1 , of the fundamental component of current owing to the presence of higher harmonic voltage components V n , can be expressed as a function of V n . It is shown that the relation for Im ΔI 1 corresponds to Groszkowski's law of reactive power balance of harmonics. An interesting relation between Re ΔI 1 and the sum of real powers of the higher harmonics is found.