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EUSO - Electric Utility System Operations
The Electric Utility System Operation (EUSO) class is the main class in PTS's series of classes. It is designed for all utility employees. The EUSO class is regularly offered in both a 2-day version and a 3-day version. Approximately 90% of the EUSO classes are the 3-day version and 10% are the 2-day version.
When done for generation plant employees, the distribution-portion of the class is minimized. When done for classes with no generating plant employees, the generation portion of the class is minimized. In all 2-day classes, only a cursory description is provided of reactive power (VArs) and capacitors, while in the 3-day version approximately 2-1/2 hours are dedicated to VArs and capacitors in order to provide a comprehensive understanding.
Who Should Attend?
The EUSO class is designed for any employee whose job performance will benefit from a basic understanding of the operations side of the business. This includes those from legal, rates, engineering, purchasing, computer application, marketing, customer service, inventory control, finance, accounting, safety, risk analysis as well as those from generating plants.
The group least likely to benefit from this class are non-technically-oriented employees with less than 6 months with the utility.
One goal for this class is to have students leave with the ability to easily identify all of the electrical equipment they see in a substation as they walk by, along with all the equipment found on the poles in a residential area.
What Does the EUSO Class Cover?
The EUSO class assumes no electrical background, and builds on the basics to provide a comprehensive understanding of the equipment and operations. It covers generation, transmission, and distribution in the same amount of detail, covering distribution down to the 120/240 residential connections. This class details how all key pieces of equipment are built, how the equipment operates, and how the equipment functions in the overall operations of a utility system. It integrates equipment construction and operations in describing a utility. It is structured to provide employees with the same technical understanding that engineers receive, but this understanding is provided without the complex mathematics that engineers learn.
The class starts with generation, explaining how any conductor in a changing magnetic field produces a voltage. This basic law is used to describe how a generator is built. Stacking a stator, winding and wedging a stator, and stator cooling systems are described in detail. The generator field is described in detail, covering both collector-ring and brushless excitation systems. Generator voltage control is incorporated in the discussion of generator excitation. A key part of this part of the class is a clear and easy way to differentiate between AC and DC. Another key component of this part of the class is the difference between single-phase and 3-phase systems.
Once the construction of generators is completed, prime movers are covered including steam turbines, hydroelectric turbines, gas turbines (also called combustion turbines), wind turbines and internal combustion engines.
System operations, regarding matching generation to load, is then covered. The use of daily demand curves (also called load curves), and annual demand curves are described in their use of assigning generators to the system. Economic dispatch is emphaisized. System frequency, automatic generation control (AGC) and generator governor-control systems are included. Sales between neighboring utilities is covered followed by sales between utilities that are not directly connected. Wheeling and wheeling contracts are fully explained. Generation ramping into and out of a contract is fully described. Inadvertent exchanges, loop flow, transmission line relief (TLR) strategies and operations are discussed. Some of these include "brownouts"; blackouts; disconnecting heat pumps, air conditioning units, and electric hot water heaters; using the media; interruptible customers; real-time pricing; and using customer generators.
The use of underfrequency load shedding is described in the event of a catastrophic loss of generation. Major North American electric utility events are incorporated into this part of the class. Immediately after the California crisis in 2001, the history of what caused California's problems is covered. After the August 14, 2003, North Eastern outage, a detailed description is provided showing what lead to the outage. Any major disturbance, including the 1965 eastern outage, may be covered in this section, depending on interest from the class.
The class then discusses conductors including wire, cable and bus. Grounding follows with emphasis on the danger of step potential that occurs when a power line hits the ground. Construction equipment into power lines and power lines lying on cars are covered with emphasis on the fallacy that tires protect people in these scenarios.
The class then discusses power and energy in detail in a manner that firmly locks into each students mind, the difference between the two. Faults and fault current are first introduced at this time. The impact of air temperatures on transmission line loading is covered at this time.
The next part of the class tackles the least understood part of utility operations, reactive power which is also described as power factor. Reactive power is clearly described including its unit of measure, VArs. The negative impact of VArs on a utility's financial position is shown from two different perspectives. It is shown from a capital expenditure perspective, and from an expense viewpoint. These two perspectives clearly explain why VArs are such an important part of efficient operations. The use of capacitors is described showing in a simple way exactly how they correct power factor. This explanation is done with math, without vectors and without the power triangle in a way that everyone understands. A 10-minute discussions then brings 7th grade math into the class for about 10 minutes as the power triangle is described.
Next, shunt reactors are fully described showing clearly how they impact power factor. This part of the class ends with a detailed discussion of how generators can provide VArs by acting as capacitors during high-load periods, and how the same generators can act as shunt reactors during light-load periods.
Power transformers follow. The laws of magnetic fields are used to describe the construction and operation of transformers. Core laminations, cooling systems and bushings and step-up/step-down operations are included. Bulk power substation transformers, distribution substation transformers and both pole-mount and pad-mount transformers end this session as power is brought into a residential customer from the generating plant.
The laws of magnetic fields are then applied in describing the construction, purpose, appearance and operation of potential transformers (PT) and a current transformer (CT).
Next, the third and last piece of major equipment is covered, circuit breakers. Oil, air, air-blast, vacuum and SF 6 circuit breakers are covered. Where they are found, their purpose, how they operate and how to differentiate them in appearance from transformers in a substation is covered. Protective relays, including time and instantaneous overcurrent, over voltage, undervoltage, bus differential and others, are included with circuit breakers.
Circuit breakers are followed, in the class, by fuses. The purpose, appearance and electrical design locations of fuses are provided. Switches and circuit switchers come next. Their purpose, appearance and electrical design locations are included. This part of the class describes the factors in determining whether a substation-design engineer chooses a fuse, a circuit switcher or a circuit breaker.
Autotransformers are clearly described in basic design and in principles of operations. The economic aspects of autotransformers are also included. Autotransformers are followed by voltage control using load tap changers, voltage regulators and capacitors.
Transmission line conductors and porcelain and polymer insulators come next in the class. Students learn how to determine a line's voltage by counting the bells of porcelain insulators. Lightning protection follows with emphasis on grounding, shielding and MOV arrestors.
Load factor (also called demand factor) is then covered. The last part of the class begins with a thorough discussion of demand charges, including those with ratchets. The class ends by bringing together energy charges with power factor charges (also called kVar charges and reactive charges) and demand charges to which larger customers are subject.
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