RELIABILITY ASSESSMENT IN BULK POWER SYSTEM (GENERATION AND TRANSMISSION)
Doaa Adel Hassan Sabry;
Abstract
5.1 Conclusions
The objective in composite system reliability evaluation is to examine the adequacy of the combined generation and transmission system with respect to the system demand at its terminal stations. The RBTS is used in this thesis. Substations and switching stations (stations) are important elements and are energy transfer points between power sources, transmission lines and customers. The reliability of a composite system is a function of the reliability of all the components in the bulk system. The individual station components and the station configurations are important elements in the bulk system. The purpose of this thesis is to measure the expected reliability indices in the RBTS and in The RBTS with different station configurations. Consideration of station related outages in composite system reliability analysis is a very important task and has received considerable attention from power system researchers in the past. The effects of station related outages can propagate to other parts of a system and cause severe damages. Stations are node points in a power system that control and monitor the flow of electric current and therefore failures in stations can significantly affect the load point supply.
Bulk system reliability can be evaluated either by using analytical techniques (which applied in this thesis) or by the application of Monte Carlo simulation methods. Monte Carlo simulation has been used to perform assessments including complex operating conditions and hasn't applied in this thesis. Three basic analytical simulation techniques designated different methods have been described. The ETAP software used in this thesis. It based on the state sampling approach and is designed to conduct reliability and reliability worth assessments of composite systems.
State space diagrams were used in order to understand the outage process and incorporate the effects of station component failures. Station components such as circuit breakers, busbars and transformers are modeled and common terminal failures due to station related outages causing failures of two or more station terminals are described. The equations required for incorporating station related outages in HL-II reliability studies are relatively simple.
The reliability analysis conducted on the RBTS shows that the use of ring bus configurations results in significantly higher reliability indices than that found for the other station configurations. These analyses assume that the busbar failure rates are the same for different station configurations. This may not be the case for all utilities. The load point and system reliability indices are evaluated and compared for the RBTS and the modified RBTS with ring bus, double-bus double-breaker, one and one half breakers and one and one third breakers configurations. Reliability analyses for the RBTS with the four different station schemes show that double-bus double-breaker configurations are the most reliable and ring bus configurations are the least reliable. The double-bus double-breaker configurations, however, are the most expensive and require the most equipment.
The load point and system reliability indices in the original RBTS are dominated by the indices at Station 6 due to the radial line supply to this bus. The system was modified in order to more clearly focus on the effects of station outages. Reliability studies show that the modified RBTS with ring bus schemes is the least reliable system. The EENS for the system with double bus double breaker, one and one half breaker and one and one third breaker schemes are very similar.
The load point and system EENS for the composite systems increase as the circuit breaker failure rates and busbar failure rates increase while the impacts of their variations are different.
The reliability indices for the modified RBTS with ring bus schemes are more sensitive to variations in the bus bar failure rates than to variations in the circuit breaker failure rates. Double bus double breaker, one and one half breaker and one and one third breaker schemes are more sensitive to variations in the circuit breaker failure rates than to variations in the circuit breaker maintenance rates and bus bar failure rates.
The variations in the circuit breaker failure rates have the most significant effect on the reliability performance of the system with one and one third breaker schemes. One and one half breaker schemes are relatively more sensitive to variations in circuit breaker failure rates than double bus double breaker schemes. Station configurations play an important role on the load point and system reliability performance of a composite system.
The conclusions drawn from the analysis presented in this thesis can be applied to larger composite systems. It is expected that the techniques and the concepts presented in this thesis should be useful to electric utility planners and decision makers.
5.2 General Discussion
Reliability study and evaluation is an important part of electric power network analysis .By a detailed reliability index analysis, the weak points in system design can be detected and ways for their corrections can be determined As a summary of the result of the thesis it is found that the reliability and availability of the outgoing feeder increased, when:
1. The reliability of the electrical components is increased.
2. Choosing the suitable design structure for the substation.
3. The location of the load point near the feeding source points.
4. Decreasing the repair time by providing qualified repairing teams, with sufficient tools and spare parts.
5.3 Future Work
- Electric Generation Reliability of Wind Energy System
The importance of renewable energy sources has increased rapidly due to run out of fossil fuels and environmental effects of conventional energy production systems. As one of the renewable energy sources, wind energy has considered to be a leading alternative energy source by reason of vast energy potential of wind. Consider the effected of both Wind energy system in stand-alone and grid connected configurations.
The objective in composite system reliability evaluation is to examine the adequacy of the combined generation and transmission system with respect to the system demand at its terminal stations. The RBTS is used in this thesis. Substations and switching stations (stations) are important elements and are energy transfer points between power sources, transmission lines and customers. The reliability of a composite system is a function of the reliability of all the components in the bulk system. The individual station components and the station configurations are important elements in the bulk system. The purpose of this thesis is to measure the expected reliability indices in the RBTS and in The RBTS with different station configurations. Consideration of station related outages in composite system reliability analysis is a very important task and has received considerable attention from power system researchers in the past. The effects of station related outages can propagate to other parts of a system and cause severe damages. Stations are node points in a power system that control and monitor the flow of electric current and therefore failures in stations can significantly affect the load point supply.
Bulk system reliability can be evaluated either by using analytical techniques (which applied in this thesis) or by the application of Monte Carlo simulation methods. Monte Carlo simulation has been used to perform assessments including complex operating conditions and hasn't applied in this thesis. Three basic analytical simulation techniques designated different methods have been described. The ETAP software used in this thesis. It based on the state sampling approach and is designed to conduct reliability and reliability worth assessments of composite systems.
State space diagrams were used in order to understand the outage process and incorporate the effects of station component failures. Station components such as circuit breakers, busbars and transformers are modeled and common terminal failures due to station related outages causing failures of two or more station terminals are described. The equations required for incorporating station related outages in HL-II reliability studies are relatively simple.
The reliability analysis conducted on the RBTS shows that the use of ring bus configurations results in significantly higher reliability indices than that found for the other station configurations. These analyses assume that the busbar failure rates are the same for different station configurations. This may not be the case for all utilities. The load point and system reliability indices are evaluated and compared for the RBTS and the modified RBTS with ring bus, double-bus double-breaker, one and one half breakers and one and one third breakers configurations. Reliability analyses for the RBTS with the four different station schemes show that double-bus double-breaker configurations are the most reliable and ring bus configurations are the least reliable. The double-bus double-breaker configurations, however, are the most expensive and require the most equipment.
The load point and system reliability indices in the original RBTS are dominated by the indices at Station 6 due to the radial line supply to this bus. The system was modified in order to more clearly focus on the effects of station outages. Reliability studies show that the modified RBTS with ring bus schemes is the least reliable system. The EENS for the system with double bus double breaker, one and one half breaker and one and one third breaker schemes are very similar.
The load point and system EENS for the composite systems increase as the circuit breaker failure rates and busbar failure rates increase while the impacts of their variations are different.
The reliability indices for the modified RBTS with ring bus schemes are more sensitive to variations in the bus bar failure rates than to variations in the circuit breaker failure rates. Double bus double breaker, one and one half breaker and one and one third breaker schemes are more sensitive to variations in the circuit breaker failure rates than to variations in the circuit breaker maintenance rates and bus bar failure rates.
The variations in the circuit breaker failure rates have the most significant effect on the reliability performance of the system with one and one third breaker schemes. One and one half breaker schemes are relatively more sensitive to variations in circuit breaker failure rates than double bus double breaker schemes. Station configurations play an important role on the load point and system reliability performance of a composite system.
The conclusions drawn from the analysis presented in this thesis can be applied to larger composite systems. It is expected that the techniques and the concepts presented in this thesis should be useful to electric utility planners and decision makers.
5.2 General Discussion
Reliability study and evaluation is an important part of electric power network analysis .By a detailed reliability index analysis, the weak points in system design can be detected and ways for their corrections can be determined As a summary of the result of the thesis it is found that the reliability and availability of the outgoing feeder increased, when:
1. The reliability of the electrical components is increased.
2. Choosing the suitable design structure for the substation.
3. The location of the load point near the feeding source points.
4. Decreasing the repair time by providing qualified repairing teams, with sufficient tools and spare parts.
5.3 Future Work
- Electric Generation Reliability of Wind Energy System
The importance of renewable energy sources has increased rapidly due to run out of fossil fuels and environmental effects of conventional energy production systems. As one of the renewable energy sources, wind energy has considered to be a leading alternative energy source by reason of vast energy potential of wind. Consider the effected of both Wind energy system in stand-alone and grid connected configurations.
Other data
| Title | RELIABILITY ASSESSMENT IN BULK POWER SYSTEM (GENERATION AND TRANSMISSION) | Other Titles | حسابات العول لمنظومة الكهربية من المستوى الفوقى الثانى | Authors | Doaa Adel Hassan Sabry | Issue Date | 2015 |
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