Power System Security and Reliability

Reliability centered maintenance (RCM) has a key role in the quality system of thermal power plants. Electricity production is definitely not only production of a product, but also becomes a customer service. Reliability is the top quality tier of this service. Incorporation in the Integrated energy system means fast transformations of organization on all levels. The reliability of modern generation components basically influences the efficiency and capacity of a power plant as a whole. This paper presents the results of RCM practice on Unit Two of The Thermal Power Plant ″Nikola Tesla -B″, 2x600 MW, Yugoslavia. RCM implementation on current problems during exploitation emphasized problems with the boiler tubing system. The methodological approach included outages analyses, marking of the most significant ones, determination of main causes of damage (determination of the material exhaustion state based on expert analyses), application of adequate remaining life assessment methodology and finally the recommendations. Based on these analyses, certain technical solutions were performed and as a result, the mean time between failures of the plant increased, as well as its reliability. According to cost efficiency, RCM methodology presented the most effective cost-benefit method for reliability upgrade.

At present, illegal usage of electricity is a serious problem facing the power industry in many countries. An efficacious and worthwhile solution to counteract this problem can be realized by using: a) already existing electrical network for communication i.e. PLC(Power Line communication) b) smart metering system. In the prototype of detection system presented in this paper, test signal at high frequency is transmitted through the network and software at supplier's end compares data with reference data. Based on the outcome of this comparison, it can remotely be detected if there is any illegal electricity usage or not. The study documented in this paper puts forward a new and unprecedented current-based technique to tackle the problem of illegal electricity usage. This paper reveals the existence of very small line current during the detection test which proves to be the key to unlock the problem of illegal electricity usage detection.

The probabilistic reliability assessment of large power systems is a very complicated and computation intensive task. So the standards of reliability be specified and used in all three sectors of the power system, i.e. generation, transmission and distribution. Since the forced outage rates (FOR) of generating plants is actually uncertain, security and reliability are two important challenges in modern power networks. That is why the reliability of a power system is always a major concern to power system planners. Because of different loss of load probability in different buses, it is necessary to change the prices of customers pay considering their loss of load probability (LOLP). This paper presents an effective simulation method for the reliability assessment of reliability index, LOLP by using segmentation method. This method is applied to Bangladesh power system (BPS) by considering uncertainties of generation. The segmentation method is used because of its computational efficiency. BPS has a total installed capacity of about 6545 MW. The maximum demand of BPS is about 5700 MW. The relevant data of the generators and hourly load profiles are collected from the National Load Dispatch Center (NLDC) of Bangladesh and the reliability index 'LOLP' is assessed for the last six years (2007-2012). Index Terms—segmentation method, forced outage rate (FOR), Bangladesh power system (BPS), probability density function (PDF), loss of load probability (LOLP).

Reliability modeling is the most important discipline of reliable engineering. The main purpose of this paper is to provide a methodology for discussing the vague environment. Actually we discuss on Bayesian system reliability and availability analysis on the vague environment based on Exponential distribution under squared error symmetric and precautionary asymmetric loss functions. In order to apply the Bayesian approach, model parameters are assumed to be vague random variables with vague prior distributions. This approach will be used to create the vague Bayes estimate of system reliability and availability by introducing and applying a theorem called "Resolution Identity" for vague sets. For this purpose, the original problem is transformed into a nonlinear programming problem which is then divided up into eight subproblems to simplify computations. Finally, the results obtained for the subproblems can be used to determine the membership functions of the vague Bayes estimate of system reliability. Finally, the sub problems can be solved by using any commercial optimizers, e.g. GAMS or LINGO.

Reliability centered maintenance (RCM) has a key role in the quality system of thermal power plants. Electricity production is definitely not only production of a product, but also becomes a customer service. Reliability is the top quality tier of this service. Incorporation in the Integrated energy system means fast transformations of organization on all levels. The reliability of modern generation components basically influences the efficiency and capacity of a power plant as a whole. This paper presents the results of RCM practice on Unit Two of The Thermal Power Plant ″Nikola Tesla -B″, 2x600 MW, Yugoslavia. RCM implementation on current problems during exploitation emphasized problems with the boiler tubing system. The methodological approach included outages analyses, marking of the most significant ones, determination of main causes of damage (determination of the material exhaustion state based on expert analyses), application of adequate remaining life assessment methodolog...

Reliability modeling is the most important discipline of reliable engineering. The main purpose of this paper is to provide a methodology for discussing the vague environment. Actually we discuss on Bayesian system reliability and availability analysis on the vague environment based on Exponential distribution under squared error symmetric and precautionary asymmetric loss functions. In order to apply the Bayesian approach, model parameters are assumed to be vague random variables with vague prior distributions. This approach will be used to create the vague Bayes estimate of system reliability and availability by introducing and applying a theorem called " Resolution Identity " for vague sets. For this purpose, the original problem is transformed into a nonlinear programming problem which is then divided up into eight subproblems to simplify computations. Finally, the results obtained for the subproblems can be used to determine the membership functions of the vague Bayes...

The ultrasonic motion detector devices emit ultrasonic sound energy into an area of interest (monitored area), and this further reacts to a change in the reflected energy pattern. The system uses a technique that is based on a frequency shift in reflected energy to detect a movement or change in position (motion). In this system, ultrasonic sound is transmitted from the transmitting device which is normally in the form of energy. The transmitted sound utilizes air as its medium and this travel in a wave type motion. The wave is reflected back from the surroundings in the room/hallway and the device hears a pitch characteristic of the  protected environment. In this system, the wave pattern is disturbed and reflected back more quickly, thus increasing the pitch and signaling an alarm whenever motion is detected. The main contribution of this work is the design of a circuit that can sense motion through movement of anything, a low cost and  portable motion detector, and thedesignof a circuit that can be used to trigger another circuit whether to ON or OFF depending on the circuit attached to it. Generally, the design is made to detect movement or moving object in a an enclosed area. In this work, a transmitter transducer generates a signal at a  frequency of 40khz, and when the signal is blocked by any moving object, and this in turn, triggers a buzzer via a timing circuit. This system works on the principle of the signal interference by a moving body, and the system is dependent on the presence of an intruder or moving object within a monitored area. The system after design and construction was tested and found to work in accordance with specifications.

This paper presents a novel method to solve security based optimal placement and parameter setting of
unified power flow controller (UPFC) problem based on hybrid group search optimization (HGSO)
technique. Firstly, HGSO is introduced in order to solve mix-integer type problems. Afterwards, the proposed
method is applied to the security based optimal placement and parameter setting of UPFC problem.
The focus of the paper is to enhance the power system security through eliminating or minimizing the
over loaded lines and the bus voltage limit violations under single line contingencies. Simulation studies
are carried out on the IEEE 6-bus, IEEE 14-bus and IEEE 30-bus systems in order to verify the accuracy and
robustness of the proposed method. The results indicate that by using the proposed method, the power
system remains secure under single line contingencies.

The availability and reliability of power supply are vital to socioeconomic development. Nigeria is the most populous country in Africa with electrical power generation that is just a fragment of the energy demands of the populace. In this study, we analyzed the trend of power generation and losses in the Nigerian power system. The average peak power generated over the study period is just 4229.39MW which is approximately 23.5MW per million people. This is meagre when compared with about 500MW per million people in South Africa. Therefore, adequate and sustainable effort are required in terms of investment and management at the generation, transmission and distribution levels toward ensuring improved power supply in Nigeria. There is a need to introduce renewable energy sources into the energy mix at the national level in order to reduce environmental pollution, and also to promote the use of sustainable alternative energy sources at the household and industrial level which will sti...

Hourly wind power ramps in ERCOT are studied by applying extreme value theory. Mean excess plot reveals that the tail behavior of large hourly wind power ramps indeed follows a generalized Pareto distribution. The location, shape, and scale parameters of generalized Pareto distribution are then determined by using mean excess plot and the least square technique, from which risk measures including α quantile value at risk and conditional value at risk are calculated.

At present, illegal usage of electricity is a serious problem facing the power industry in many countries. An efficacious and worthwhile solution to counteract this problem can be realized by using: a) already existing electrical network for communication i.e. PLC(Power Line communication) b) smart metering system. In the prototype of detection system presented in this paper, test signal at high frequency is transmitted through the network and software at supplier's end compares data with reference data. Based on the outcome of this comparison, it can remotely be detected if there is any illegal electricity usage or not. The study documented in this paper puts forward a new and unprecedented current-based technique to tackle the problem of illegal electricity usage. This paper reveals the existence of very small line current during the detection test which proves to be the key to unlock the problem of illegal electricity usage detection.