Abstract
- Introduction
- 1. Description of the subject area
- 2. The content of the abstract
- 3. Vitality unit load
- 4. The probability of coincidence in space and time of two events
- List of sources
Introduction
Background. n short circuits ( short circuit ) and a network element failure in the operation of a number of protective switching devices through which passed a through current emergency and launched the appropriate current protection relays , there is the so-called chain accidents [1]. In chain crash damage accounted for 90% of electricity consumers [2]. Because of work aimed at clarifying the calculation methods are very relevant.
The purpose of the work. Specification of mathematical model for calculating the reliability of load nodes.
Scientific innovation. Getting a new dependence probable loss vitality unit load over time T of the frequency of short circuit in the area of defense comutation apparatus.
Practical value. Development of methodology for assessing the survivability of load nodes..
The content of the abstract.When operating substations are three modes of operation : static, dynamic and repair.
In static mode takes into account damage elements of the open circuit
. These failures should be attributed failure in secondary circuits of relay protection and automation, accompanied breaker, false positives and unnecessary protection.
In dynamic mode are taken into account failure of the short circuit
(SC) and the refusal of system operation at circuit breaker in the area of ??its current protection .
Damage type SC
may occur in the network elements (on leaving the switching devices lines, tires, a disconnector, transformer , etc.). Through which flows the initial emergency work and currents.
In repair mode takes into account errors of staff at various repair switching which can lead to accidental disconnection unit load.
Vitality node will assume the load capacity of consumers and their automatic remedies resist changes that lead him to the emergency shutdown.
Picture 1 – The probability of failure in the match and triggered a short circuit in time
(animation: 6 frames, 7 repetition cycles, 55 kilobytes)
Chance of coincidence in space and time of two events : SC
in the network element and denial operation system shutdown switch can be estimated using the following formula:
Where
Roots 
are found by solving cubic equations:
- flow parameter SC
in the area of ??the relay switching apparatus
- failure flow parameter in the triggering system shutdown switch
- Average response time of the system shutdown switch with SC
in the zone of action
If the system shutdown protective switching device tested after a certain time interval 
and verify absolutely reliable, then 
can be determined from the expression [3]
Where 
- the average time of system shutdown switch detection refused to state.
Knowing options: 
and the time interval between diagnosis system disconnecting switches seems to predict survivability unit load and if it does not comply with existing regulations that 
.
In the event that by reducing impossible, impractical to provide a normalized level in this case is not required to use a switching device with high reliability pain - .
In writing this essay master's work is not yet complete. Final completion: December 2015. The full text of work and materials on the topic can be obtained from the author or his scientific adviser after that date. This part of the essay only sightseeing. Further work will focus on experimental research and revision of existing results.
References
- Кутишин В.Г. Определение характеристик отказов системы при цепочном развитии аварий. – Изв. АНСССР Энергетика и транспорт, 1977 №3 с.20-30.
- Гук Ю.Б. Анализ надежности электроэнергетических установок – Л.: Энергоатомиздат, 1988 224с.
- Ковалев А.П. , Шевченко А.В., Белоусенок И.В. Оценка пожарной безопасности передвижных трансформаторних подстанций 110/35/6 кв. – Промышленная Энергетика, 1991, №6 с.15-19.