الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Electricity is considered the main basic of development and growth in all activity such as industrial, agriculture and medical of activity. Main advantage of electrical energy are comfortable and clean than any other energy. Due to over population on world level, besides ajdition technical in all used perform that to increase using of electrical power in all fields and became described as principal and fundamental of life. Electrical device is available in all place such as plant, house, library and workshop. Whether in city or village.
Electric element of electrical systems such as circuit-breakers, transformers, motors and generators etc. are very important and when fault or defect happen in it will cause discontinuity of electrical supply for consumer. As the result of interruption of electric supply lead to harm and loss for consumer. For example in hospital many of surgical operation depend on equipments and devices cannot used without electricity. Some of industrial production cannot bear sudden interruption.
For reduced of the electrical equipment failure can be reduced by performing work program of testing, commissioning and maintenance to these equipment based on scientific basic for insurance of source continuity.
Circuit-breakers are mechanical switching devices able to make, carry and interrupt currents occurring in the circuit under normal conditions, and to carry for a specified time and to make and interrupt currents arising in the circuit under defined abnormal conditions (e.g short circuit).
Transformers are machines concerned to transport and distribute electrical energy at different potentials. With respect to consumer it is considered the main source of feeding. Transformers are classification to power transformers, distribution transformers and instrument transformers.
Instrument transformers include measuring and protective current transformers and voltage transformers, these transformers which are used in conjunction with measuring instruments, protection relays and control circuits.
Electric motors are machines to change of electrical energy to mechanical energy which can be used in numerous fields.
According to the potential of all systems we show of definition and classification for some of electrical equipment such as circuit-breakers, transformers, motors and generators. Add to that show the type tests which it can determine the characteristics and identification. Also routine tests which show the pursuit and periodic maintenance. After installation the electrical equipment are subjected to commissioning tests are conducted on site to ensure proper assembly and operational readiness of the equipment. Maintenance of electrical equipment are main cause to live long of the electrical equipment and for reduced offaults.
In this report the testing, commissioning and maintenance of some of electrical equipment based on scientific basic and according to international standards are presented. Also a studying performance of some problems on electrical equipment in Behira company for electricity distribution by sector Elsahel Elshamale and Matroh of medium voltage I 1, 22 k V are illustrated
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to point out the importance of testing, commlsslomng and maintenance of these equipment. These problems are as follows:
- Problem in circuit breakers leaded to repeated trip for the main source (substation) after check the element of system the inspectors discover that there is low insulation resistance for some of circuit breakers.
- Problem when supervisor of station of reinforced water during using reserve transformer they failed in spite of the performed tests proved that reserve transformer is acceptable. On testing of protection system the investigators deduce there is wrong in its element.
- Problem in trip feeder of Ghazala bay which resulted transformer 2 in low insulation resistance causes that didn’t perform periodic maintenance.