Bus Voltage Phase Angles Research Articles

Power quality improvement using interline voltage controller

The concept of an interline voltage controller (IVOLCON) to improve the power quality in a power distribution system is discussed. An IVOLCON consists of two shunt voltage source converters (VSCs) that are joined through a common dc bus. The VSCs are connected to two different feeders. The main aim of the IVOLCON is to control the PCC (Point of Common Coupling) bus voltages of the two feeders to pre-specified magnitudes. The phase angles of the PCC bus voltages are obtained such that the voltage across the common dc link remains constant. The structure, control and capability of the IVOLCON are described. The efficacy of the proposed configuration has been verified through simulation studies using PSCAD/EMTDC for voltage sags and feeder outage.

Decentralised congestion management of interconnected power systems

A method for the decentralised solution of the congestion management problem in large interconnected power systems is presented. The multi-area congestion management is achieved through crossborder co-ordinated redispatching by regional transmission system operators. The co- ordination is performed through a pricing mechanism inspired by Lagrangian relaxation. The prices used for the co-ordination of the regional subproblem solutions are the prices of electricity exchanges between adjacent areas. Test results from the application of the method to the three-area RTS96 are reported. unit index, identical to bus index; for simplicity of notation it will be assumed that only one unit is connected to each bus line from bus i to bus ; index; also used for tie-lines number of buses, identical to number of units number of areas number of tie-lines cost of congestion relief associated with unit i, here a quadratic function unit active power output vector bus active power demand vector bus voltage phase angle vector reference bus voltage phase angle network admittance matrix admittance of line ij power flow on line ij area (region) index

Approach for bus frequency estimating in power system simulations

Bus frequency affects the system load behaviour in time domain simulation of power systems. The most common methods for estimating bus frequency are by taking weighted averages of the speeds of synchronous machines or by taking time derivatives of the phase angles of bus voltages. These methods cause a simulation accuracy problem or even give wrong results. A new approach for estimating bus frequency is introduced. This takes into account the factors of both machine speeds and phase angles of bus voltages, which is shown to be more accurate in bus frequency estimation and will not increase computer simulation time.

APPROXIMATE SUB-OPTIMUM TECHNIQUES FOR OPTIMAL POWER FLOW

ABSTRACT Guided by the close dependence of the real power on the bus voltage phase angles (P-8), and of the reactive power on the bus voltage magnitudes (Q-V), a new approximate formulation of power flow optimization is developed. The proposed formulation exploits this decoupling and consequently reduces the problem size, computer memory and the solution time. The method has considerable potential for real time applications. Approximate models are preferred for sub-optimization modules. The errors induced by ignored set of power flow equations, which are the major limitations common to all approximate models, are overcome by the proposed formulations.

Power System Harmonics Estimation and Monitoring

ABSTRACT The existence of harmonics in power systems and their effects have led to numerous issues of electric power quality. The IEEE Standard 519 is being revised and upgraded from a guide to a recommended practice in order to set limits on harmonic distortion and to ensure a high power quality. Thus, the measurement of harmonics in power system has assumed considerable significance because the need of monitoring the power system harmonic content. In this paper dynamic state estimation of power system harmonics is used to estimate the system bus voltage magnitudes and phase angles at different harmonic levels. These estimated variables are used to calculate harmonic factors and indices that are used to obtain the harmonic profile of the system. The term “power system harmonic monitoring” is proposed to collectively refer to the calculation of total harmonic distortion, distortion index, telephone influence factor, C-message index, and the KVT and KIT factors. The IEEE 30 bus system, with three six-pulse...

Measurement of Bus Voltage Angle Between Montreal and SEPT-ILES

A new and precise measurement of bus voltage phase angle is described. We will show how the use of two adequately synchronized clocks allows an accurate measurement to be made of a bus voltage angle in real time. We describe the method used for synchronizing the clocks by means of LORAN C signals. We give experimental results of the bus voltage angle which was measured every second with a precision better than one degree.

A linear load flow technique for power system reliability studies

In power system reliability applications, an approximate load flow solution of each contingency state is normally sufficient to determine if the desired limits of bus voltages and line ratings have been violated. The total possible line outage states to be investigated for a practical system are very large. A.C. load flow techniques are computationally expensive whereas a d.c. load flow technique does not provide the bus voltage magnitudes. In this paper, a load flow technique which provides an approximate solution of the bus voltage magnitudes and phase angles in a single iteration is described. The suitability of this approach for obtaining load flow solutions of test systems ranging from 5 to 118 buses is briefly discussed. The effectiveness of this technique for contingency evaluation is also investigated.

Loss formulas from functions of voltage angles

A NEW APPROACH in the form of remarkably simple formulas for the determination of incremental transmission losses in electric power systems has been advanced by Brownlee.1 He derived the formulas for the simplest possible transmission system of two generators connected by a single transmission line, and then showed that they were applicable to practical power systems by working out some numerical cases. Brownlee's formulas are functions of the phase angles of the generator bus voltages, so that their application is restricted to those cases where the phase angles are known, such as a-c network analyzer studies.