Single Wire Earth Return System Research Articles

ANALISA JARINGAN DISTRIBUSI TEGANGAN MENENGAH DENGAN SISTEM SINGLE WIRE EARTH RETURN UNTUK WILAYAH TERTINGGAL, TERDEPAN DAN TERLUAR

Indonesia's rural electrification rate (RER) is still low. This is due to the high cost of installing a conventional three-phase or single-phase power supply in distributed rural loads. However, the Rural Energy Agency and the National Utility have made many efforts to address this issue. To this end, this document proposes a Single Wire Earth Return (SWER) electrification scheme for the electrification of a selected village, namely Serang, Banten. Field data were collected and used to design a potential SWER distribution network. A mathematical model representing SWER for Serang, Banten was developed and simulations were performed to determine soil potential and soil resistance. These two are important every time you install a HEAVY line. In addition, a technical and economic comparison was made in order to determine the short-term costs of the proposed SWER with the existing single-phase two-wire (SPTW) system. The technical and economic analysis shows that the proposed SWER system will achieve a cost saving of 50% compared to the installation of the SPTW system for Serang Banten electrification.

Feasibility analysis of single wire earth return system for potential application in rural electrification in Nigeria

<span>Traditionally, three-phase networks are used to transmit electric power to consumers. However, due to its high initial cost, many isolated rural communities are yet to have access to electricity. Thus, the single wire earth return (SWER) architecture, which uses the earth as the return path, attracts significant cost savings. In this paper, the potential application of the SWER system for rural electrification in Nigeria was presented. The cost-effectiveness of the SWER system which is about 70% less than the three-phase configuration, is due to the need for fewer cables, pole-top fittings, switching, and protection devices. Initially, the dynamic modeling of the equivalent SWER system was derived for the MATLAB simulation analysis. The pertinent parameters of the realized system, namely, micro-former leakage reactance, the resistive and inductive value of the single-phase network, were determined and employed for the SIMULINK and the repetitive power flow analyses. The results obtained from the power flow analysis and the simulation models for different loading conditions were found to agree with an error margin of +5%. This demonstrates that the proposed prototype can be adopted to reduce the prevalent energy poverty and thereby improved the quality of life of rural dwellers in Nigeria.</span>

Comparative Analysis of Rural Electrification Options: Single Wire Earth Return System vs. Solar Pv-Battery vs. Hybrid Solar Pv-Lpg Generator

Comparative Analysis of Rural Electrification Options: Single Wire Earth Return System vs. Solar Pv-Battery vs. Hybrid Solar Pv-Lpg Generator

Assessment of Distributed Generation on the Efficiency of Single Wire Earth Return Systems

Single-wire earth-return (SWER) systems are low capital and maintenance cost distribution systems, which have been chosen and widely built in many rural parts of the world. While low load density is main cause of over voltage phenomenon, voltage drop problems caused by continuously increasing electricity consumption is more common and requires urgent attention in order to enhance system capacity and reliability of aging SWER systems. This paper will investigate potential alternatives for given problem, include conventional solution such as capacitor bank compensation. Case studies on the Wambo Creek SWER system are used to assess the impacts of integration of renewable or distributed generation against other mitigations and the issues are discussed.

Projeto de aterramento para sistema monofilar com retorno pelo terra

Este trabalho apresenta o projeto de aterramento elétrico para Sistema Monofilar com Retorno pela Terra (MRT), em solicitações de baixas frequências, utilizando-se o método das imagens e considerando a simplificação do método dos potenciais constantes. Simulou-se o comportamento de três diferentes configurações de aterramento: hastes em triângulo, em quadrado vazio e para nove hastes, formando uma malha com quatro quadrados. A partir da simulação obtiveram-se o valor da resistência de aterramento para cada configuração e os potenciais gerados na superfície do solo. Com base nesses resultados foi possível comparar os valores tabelados para resistências mínimas, em função da potência do transformador, aplicados para diferentes concessionárias de energia que utilizam o Sistema MRT, com os valores calculados que mantêm os potenciais no solo em níveis seguros para seres humanos e animais. Os resultados mostraram que é possível utilizar aterramentos mais simples e mais baratos, pois os gradientes de tensões no solo se mantiveram em níveis seguros.

Energy injection by distributed generation for enhancement of voltage profile in SWER systems

A system with Distributed Generation (DG) has greater load carrying capacity and can correct for a poor voltage profile during peak loading. This paper addresses the loading patterns of rural feeders and the relative effectiveness of real and reactive injection to support voltage profile in Single Wire Earth Return (SWER) systems. Real and reactive injection on a SWER network has been investigated and required energy for voltage enhancement estimated. DG with real and reactive injection (DG-PQ) using Q priority (DG-QPQ) can drastically reduce fuel and energy requirements compared to the amount required by proportional use of real and reactive power in DG-PQ.

Optimal Planning of Unbalanced Networks Using Dynamic Programming Optimization

This paper presents a method based on dynamic programming optimization to design distribution and industrial networks with unbalanced customers. Low-voltage and medium-voltage network customers can be three-phase (i.e., industrial and commercial) and single-phase (e.g,. residential and rural areas). Moreover, American medium-voltage distribution networks have single-phase lines (rural areas) and three-phase lines (urban and primary feeders). Optimization of an unbalanced network implies optimal assignation of single-phase customers to each phase. This works considers different conductor types, tapering, power losses in lines, capacity and voltage drop constraints and deterministic loads, all employing single-phase and three-phase lines. The necessary modifications to apply it by single-wire earth return systems is presented.

Distributed Generation as Voltage Support for Single Wire Earth Return Systems

Key issues for distributed generation (DG) inclusion in a distribution system include operation, control, protection, harmonics, and transients. This paper analyzes two of the main issues: operation and control for DG installation. Inclusion of DG in distribution networks has the potential to adversely affect the control of voltage. Both DG and tap changers aim to improve voltage profile of the network, and hence they can interact causing unstable operation or increased losses. Simulations show that a fast responding DG with appropriate voltage references is capable of reduction of such problems in the network. A DG control model is developed based on voltage sensitivity of lines and evaluated on a single wire earth return (SWER) system. An investigation of voltage interaction between DG controllers is conducted and interaction-index is developed to predict the degree of interaction. From the simulation it is found that the best power factor for DG injection to achieve voltage correction becomes higher for high resistance lines. A drastic reduction in power losses can be achieved in SWER systems if DG is installed. Multiple DG can aid voltage profile of feeder and should provide higher reliability. Setting the voltage references of separate DGs can provide a graduated response to voltage correction.

Impact of distributed generation on protection of single wire earth return lines

Distributed generation (DG) inclusion within the grid system potentially introduces problems related to control, protection, harmonics, and network transients. This paper analyses one of the key issues: protection of the network, by ascertaining the impact of rotary DG inclusion on existing protection system of SWER (single wire earth return) lines and the DG sensitivity during faults. The analysis is carried out by estimating fault-sensitivity for the worst-case situation, determining the DG impact on the existing protection scheme, and comparing the network situation with and without DG during the fault. A model of arc voltage is used to represent a fault on a SWER scheme. The size of DG is selected based on the SWER capacity and SWER load. The study is conducted on an example SWER system by considering the SWER lines with and without DG and faults on the SWER backbone and laterals, and simulation results are reported. In every case studied, the fault current from the DG significantly exceeded the DG rating and the DG would have tripped. Thus the system reverts to the case with no DG. Even if DG did not trip, the fault current from the source would be largely independent of the DG, and thus the original feeder protection would continue to provide the same quality of performance. Hence, net sensitivity and existing protection system will not be adversely affected by DG inclusion in SWER lines.