Standby diesel power plants

The literature ([5-27], [5-28], [5-29]) provides failure rates for diesel standby plants which differ by several magnitudes. However, since the question posed can only be answered with the help of quantitative analysis, a statistical analysis of the operational behavior of diesel plants is indispensable for the determination of reliable failure rates. Figure 5.26 shows how many influence factors may lead to the failure of a diesel plant. This, in turn, requires that the failure rates for standby diesel power plants be determined as to type and mode of application. For this purpose, voluminous data on the operational behavior of standby diesel plants is required. This data can never be collected from the behavior of standby diesel plants under blackout conditions alone, since these blackouts, as mentioned above, are very rare. However, there is another avenue which leads to the acquisition of failure data, namely via monthly trial runs while the public power supply is in full and normal operation. 

Figure 5.26 Causes of failures in standby diesel power plants.

Based on the studies three pilot plants are proposed and analyzed for three oil platforms at Neft Dashlari. All plants are integrated system with three main components (1) a wind generator (8 m diameter wind turbines) to produce primary energy, (2) a standby diesel-electric set, to cover the lack of energy during calm periods, and (3) a storage battery bank to cover daily imbalances between power production and power load during the day. 

The AAC source is not normally directly connected to the plant s main or standby offsite power sources or to the Class IE power distribution system, thus minimizing the potential for common cause failure. Quality assurance guidelines for the AAC are given in CESSAR-DC Section 8.3.1.1.5.5. (The emergency diesel generator reliability aspect of Station Blackout as described in Regulatory Guide 1.155 is covered in USI B-56.)... 

Operational Behavior Demonstrated in a Standby Power Plant. The plant consists of a diesel engine, the attached generator, and a number of auxiliary systems. Figure 5.25 shows the general plan of the installation. Important auxiliary systems of the plant are the fuel supply system, the lubrication system, the coolant circuits, the generator excitation system, the starter system, the air supply, and the circuitry. 

Diesel plants are used in small power plants for the continuous generation of electricity and in standby power plants for the temporary generation of electric power. In the latter case, they must be able to supply, mostly at short notice, important users with power until the temporary breakdown of the regular power supply has been remedied. These plants are located as standby units in airports, radio and TV stations, hospitals, nuclear power plants, large-scale elevator systems, etc. 

The following is a general survey of standby power plants. Due to the usually very reliable power supply from the public network, diesel plants in standby power units are very rarely called upon to perform. During blackouts (failure of the power supply), however, the standby power plant is expected to bridge the blackout reliably and with minimal loss of time during startup. Also, this must be achieved automatically. The deenergized or dead period between network failure (blackout) and emergency power supply must be as short as possible. Thus the question... 

Two onsite standby diesel generator units, each furnished with its own support subsystems, provide power to the selected plant ac loads. Power supplies to each diesel generator subsystem components are provided from separate sources to maintain reliability and operability of the onsite standby power system. 

Power is supplied to the main control room/control support area HVAC subsystem by die plant ac electrical system. In the event of a loss of the plant ac electrical system, the main control room/control support area ventilation subsystem can be transferred to the onsite standby diesel generators. The convection heaters and duct heaters are not transferred to the onsite standby diesel generator. 

The ac power cut would last for up to approximately two minutes, until such time as the onsite standby diesel generators started, warmed up and loaded or the plant operators transferred selected loads to the single reserve auxiliary transformer. This condition would result in a reactor trip, because of the loss of the four reactor coolant pumps, which are powered from the unit auxiliary transformer buses. 

Diesels are used in many industrial applications (for example, for base-load generation in mines, cement plants and in remote regions of the world). In addition, they are often utilized to provide standby power for hospitals, telecommunications, banks, computer centers and office complexes that must have full independent power capability. The diesel can be started rapidly, making it ideal for peak lopping duties to meet maximum load demands, or for emergency use in cases of power supply interruptions. 

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