Evaluation of reliability of power distribution components: A case study of Sagamu Substation, Ogun State

Power system especially the distribution system which is the closest to the consumer is very fundamental and important to a nation’s economy development and that was the reason this study titled “Evaluation of reliability of power system distribution components, a case study of Sagamu Substation, Ogun State” was carried out in response to the yawning of the consumer for reliable and stable power supply. It is indispensable to find means of shaping which component failure contributes most to the unavailability, outage or interruption of the distribution system, and how this unavailability essentially affects the customers. A year power outages data that caused as a result of failure on each of these components such as Switch gears, Supply lines (11Kv),Busbar, circuit breakers, Fuses, Switches, Outgoings feeders, Over current relays, Earth fault relays, Surge arresters, transformers e.t.c. were collected from Ibadan Electricity Distribution company (IBDEC), Sagamu Substation Zone, Ogun State and were typified in Table 1-11.The failure rate (f/yr) (λ) of transformer, switch gear, supply line (incoming),bus bars, circuit breakers, fuses, switches, outgoing feeder, over current relay, earth fault relay and surge arrester were evaluated as follows 0.0059, 0.0044, 0.0011, 0.6667, 0.0007, 0.0082, 0.0000, 0.0039, 0.0003, 0.0001 and 0.0000 respectively and others such as average outages time (hours) ,outages time hours and other basic reliability indices were calculated and illustrated in Table 12. Some of these failures were also represented in bar chart. This method relates reliability theory with the experience gained from statistics and practical knowledge of components failures and maintenance. The findings from this work revealed that fuses had the highest failure followed by transformers and the least was surge arresters and it was also discovered that the outages time was reduced during the December period. This approach can be applied to rural and urban distribution systems. This submission made reliability theory a powerful tool to assist distribution Engineers in solving difficult and complicated problems.

Application of Deep Learning and Symmetrized Dot Pattern to Detect Surge Arrester Status

Surge arresters primarily restrain lightning and switch surges in the power system to avoid damaging power equipment. When a surge arrester fails, it leads to huge damage to the power equipment. Therefore, this study proposed the application of a convolutional neural network (CNN) combined with a symmetrized dot pattern (SDP) to detect the state of the surge arrester. First, four typical fault types were constructed for the 18 kV surge arrester, including its normal state, aging of the internal valve, internal humidity, and salt damage to the insulation. Then, the partial discharge signal was measured and extracted using a high-speed data acquisition (DAQ) card, while a snowflake map was established by SDP for the features of each fault type. Finally, CNN was used to detect the status of the surge arrester. This study also used a histogram of oriented gradient (HOG) with support vendor machine (SVM), backpropagation neural network (BPNN), and k-nearest neighbors (KNN) for image feature extraction and identification. The result shows that the proposed method had the highest accuracy at 97.9%, followed by 95% for HOG + SVM, 94.6% for HOG + BPNN, and 91.2% for HOG + KNN. Therefore, the proposed method can effectively detect the fault status of surge arresters.

Análisis Matemático de la Supresión de Impulsos Tipo Atmosférico en Sistemas de Distribución

Se realizó el estudio y análisis de la supresión de impulsos tipo atmosférico al pararrayo de un Sistema de Distribución Eléctrica, basado en la comparación de resultados teóricos desarrollados con el software Matlab – Simulink y los experimentales realizados en el laboratorio de Alta Tensión de la Universidad Politécnica Salesiana del Ecuador, con el objeto de entender el comportamiento eléctrico y matemático de la protección al sistema de distribución. Se utilizó el circuito equivalente del modelo dependiente de la frecuencia de la IEEE "Modeling of metal oxide surge arresters”. El análisis matemático consistió en construir las ecuaciones del circuito equivalente y utilizar la herramienta de Matlab que extrapole con la mejor aproximación el comportamiento de las resistencias no lineales del pararrayo, además se modeló el circuito generador de impulso atmosférico definido en las normas ANSI/IEEE Standard 4-1995 requerido para la supresión.

Voltage characteristic as a parameter for surge arrester diagnosing

An alternative method for field MOV surge arresters diagnosing was observed, the controlled characteristic was the surge voltage of a gap arrester. The condenser that was connected in series with gap arrester was applied as voltage measurement sensor. Electrical aging of active elements (MOV), surge arrester insulation degradation and other types of electric faults causes to voltage increase at capacitor. The voltage value can be measured directly or the energy stored in capacitor can be transformed to electromagnetic signal and, then, registered remotely by specific radio transceiver. The capacitor connected in series with the surge arrester can also be used for leakage current limitation during all the life period of surge arrester. Shunted with a spark gap and presented as the low-current gap arrester with pre-sated discharge voltage glass (porcelain) pin-cap insulator can be the simplest, but reliable sensor. Taking into consideration modern technologies the surge arrester statement continuous monitoring system can be designed. It also allows locating the place of damaged arrester that is particularly true for remote maintenance of equipped with surge protection devices electrical