A Voltage and Power Flow State Calculation Technique of Distribution System using Measurement Values

Abstract

This paper has described a technique of calculating voltage and power flow state of a distribution system using the information measured with two or more switches with sensors installed in a distribution system. The proposed technique is that, a set of the power distribution section where two or more switches with a sensor are connected is defined as the large section, and the active power and reactive power consumption in the large section are calculated based on measurement information, voltage (RMS), current (RMS) and power factor. Using the simple distribution system model that consisted of the large sections, the power consumption of the large section is calculated by the power flow calculation to separating power consumption and power distribution loss. It is distributed to the small sections that constitute the large section, and detailed power flow calculation is performed. Verification of the proposal technique and basic estimation of the calculation error were performed using the simple power distribution system model.

Differential Evolutionary Particle Swarm Optimization for Load Adjustment Distribution State Estimation using Correntropy

“…Thus, an assumed value of load power factor is often used in state estimation of distribution systems. 4,5,7,9,[11][12][13]15…”

“…On the other hand, state estimation methods focused on distribution systems are studied recently as a fundamental technology to improve online monitoring and control in next-generation distribution automation systems that can handle introduction of renewable energies into distribution systems, increasing deregulation of power industry, and other factors. [3][4][5][6][7][8][9][10][11][12][13][14][15] Conventional techniques of state estimation for distribution systems can be divided into statistical methods [3][4][5]8 and load adjustment methods. 3,6,7 Both approaches use least squares based on the Newton method, sensitivity-based algorithms, and so on, assuming that functions of interest are continuous and differentiable.…”

“…However, models of real equipment in distribution systems include nonlinear elements, and power flow equations are not necessarily differentiable or continuous, 16 so that derivatives and sensibility cannot be used. In addition, section switches provided with sensors are introduced into distribution systems in Japan, and using these sensor data for state estimation is considered, 9,10 but errors sneak in estimation by least squares when measured results are corrupted by faults of measuring devices or communication failures, and so on.…”

A Probabilistic Estimation Method of Reactive Power Controlled by PCS using Measurement Data of Switchgears with Sensors

“…Assuming that load power factor (lagging) is uniform irrespective of the load size, the reactive power load in every LVS can be calculated using the designated active power load as shown in Eq. (10).…”

“…On the other hand, existing section switches on medium-voltage lines are being replaced with SSS (Section Switchgear with Sensors) that can measure voltage, current, and power factor. With such information, reports on monitoring [10][11][12] and operation [13][14][15] of power systems have been created. For example, in literature [11], sensor data are used for the online estimation of PV output and load in sections between SSS to determine the actual load required for fault recovery in a power distribution system.…”