Customer Load Characteristics Research Articles

Heuristic Rule-Based Phase Balancing of Distribution Systems by Considering Customer Load Patterns

In this paper, a heuristic backtracking search algorithm is proposed to adjust the phasing arrangement of primary feeders and laterals for phase balancing of distribution systems. The phase unbalance index of distribution feeders is calculated based on the phasing current magnitude of each line segment and branch, which has been solved by a three-phase load flow program. The database of an automated mapping/facility management (AM/FM) system is used to retrieve the component attributes, and the topology process is executed to determine the electrical network configuration and the customers served by each distribution transformer. By using the monthly energy consumption of customers in customer information system (CIS) and the typical daily load patterns of customer classes, the hourly loading profiles of distribution transformers and service zones can be derived to solve the individual phase loadings of each primary feeder and lateral. The phase balancing of distribution systems is enhanced by heuristic rule-based searching process to minimize the phase unbalance index. To demonstrate the effectiveness of proposed methodology, a practical distribution feeder with 2754 customers is selected for computer simulation to enhance three-phase balancing of distribution systems. It is concluded that three-phase balancing of distribution systems can be obtained by considering customer load characteristics.

Temperature Adaptive Switching Operation for Distribution Systems

This purpose of this paper is to investigate the optimal switching problem of distribution systems by considering the customer load characteristics and the effect of temperature change on customer loading. The load survey is applied to derive the typical load patterns of residential, commercial, and industrial customer classes. The power consumption of sample test customers and weather information are used to solve the hourly temperature sensitivity of power consumption for each customer class. All the customers served by each distribution transformer are identified and their monthly energy consumption is retrieved from the customer information system in Taipower. The hourly loading of each service zone and its change due to temperature rise are obtained based on the customer load consumption and its temperature sensitivity. By performing the connectivity trace to find the feeder configuration and executing the three-phase load flow analysis, the hourly current loading of line switches, distribution feeders, and main transformers in substations is solved. The binary integer programming is then applied to determine the temperature adaptive optimal switching operation for noninterruptible load transfer among distribution feeders and main transformers.

Temperature adaptive switching operation for distribution systems

This paper investigates the optimal switching problem of distribution systems by considering the customer load characteristics and the effect of temperature change to the customer loading. The load survey is applied to derive the typical load patterns of residential, commercial, and industrial customer classes. The power consumption of sample test customers and weather information are used to solve the hourly temperature sensitivity of power consumption for each customer class. All the customers served by each distribution transformer are identified and their monthly energy consumption is retrieved from the customer information system in Taipower. The hourly loading of each service zone and its change due to temperature rise are obtained based on the customer load consumption and its temperature sensitivity. By performing the connectivity trace to find the feeder configuration and executing the three-phase load flow analysis, the hourly current loading of line switches, distribution feeders, and main transformers in substations are solved. The binary integer programming is then applied to determine the temperature adaptive optimal switching operation for noninterruptible load transfer among distribution feeders and main transformers.

Application of load survey systems to proper tariff design

This paper proposes a proper rate making strategy for a public owned utility by taking into account the customer load characteristics. The load survey system has been well designed by sampling theory to find the customers for power consumption information collection. By this manner, the typical load patterns derived can effectively represent the load behavior of each customer class. The load patterns of each test customer during different seasons are solved by statistical analysis according to the load information collected. The seasonal typical load pattern of each customer class is then determined by integrating the load patterns of the same type customers. The power consumption of the customer class is then estimated by the typical class load pattern and the energy consumption of all customers in the same class, which can be retrieved from the customer information database. The typical load pattern of whole power system is then determined by aggregating the power consumption of all customer classes. The estimated system load consumption is then compared to the actual system load profile, it is found that a rather accurate system load profile can be predicted by the load survey system.

Determination of customer load characteristics by load survey system at Taipower

This paper proposes a load survey system to determine the load characteristics of various customer classes in an electric utility company. The questionnaires are adopted to find the power consumption of key electric appliances. The actual power consumption of hundreds of customers are collected by intelligent meters. Sampling theory has been applied to find the proper sample size of both questionnaires and field tests so that the customer load characteristics will be derived with sufficient confidence level. Statistical analysis is then performed to find the power consumption model of each customer class based on the power measurement of field tests. The temperature effect on the power consumption of each customer class is also investigated by differentiating the proposed power consumption model with respect to the ambient temperature. The proposed method has been adopted by the Taipower company to better understand the customer load characteristics to support various functions of power system planning and operation in a more effective manner.

Derivation of class load pattern by field test for temperature sensitivity analysis

This paper proposes systematic procedures to derive the load pattern of various customer classes in a utility company. The questionnaires are adopted to find the power consumption of key electrical appliances. The customer load information is obtained through intelligent equipment which records customers' electricity demand on a 15-minute interval basis throughout the year. Five hundred meters are installed on statistically selected samples from the various customer classes. By the proposed sampling theory, the customer load characteristics will be derived with a sufficient confidence level. Statistical analysis is then performed to find the typical load pattern of each customer class based on the power measurements of field tests. The temperature effect on the power consumption of each customer class is then solved by investigating the relationship between customer power consumption and the ambient temperature. The proposed procedure has been adopted by Taipower Company to determine the customer load pattern to provide valuable information for better distribution planning and to design better load management programs to enhance system operating efficiency.

Impact of utility switched capacitors on customer systems-magnification at low voltage capacitors

An analysis is made of the potential for magnified transient voltages at customer buses during capacitor switching on the primary distribution system. The various factors affecting this phenomena are analyzed in detail through extensive sensitivity analysis simulations. These factors include the switched capacitor size, short-circuit capacity at the switched capacitor, customer step-down transformer size, low-voltage power factor correction, and customer load characteristics. The impact of these transients on customer equipment are described, and possible solutions to control the transients are presented. >

Load Models for Large-Scale Stability Studies from End-User Consumption

This paper summarizes improvements in the application of load models in power system stability studies by utilizing end-user energy consumption data to identify the composition of loads. The project included derivation and compilation of customer load characteristics for the Ontario Hydro System and subsequent interfacing with a transient stability program. Results from these models were compared with recordings of a recent Ontario Hydro system disturbance.

Secondary System Distribution Planning for Load Growth

A computer program which determines growth patterns and characteristics of secondary distribution systems under the influences of time and load growth is described. New methods of considering the basic load characteristics of customers are employed to determine accurate system costs for future years for all growth paths permitted by specified design changes. Using present worth arithmetic, comparisons of these costs are made to determine the schedules of design changes which will result in greatest economy for the system studied.