Trifásicos

Introduction to Three-Phase Systems

Overview of the Electrical System

• The class will cover three-phase systems, starting with an overview of the general electrical system and its components in Chile.

• Discussion on balanced vs. unbalanced circuits, emphasizing the importance of equal loads for balance.

Components of the Electrical System

• The electrical system is divided into three main sections: generation, transmission, and distribution leading to residential consumption.

• Generation sources include thermal, hydroelectric, solar, wind, and others under study due to increasing energy demand.

Transmission and Distribution

• Transmission carries generated energy at various voltage levels (110kV to 500kV), while distribution operates at lower voltages (11kV to 22kV).

Types of Energy Generation

Renewable Energy Sources

• Examples of renewable generation include onshore and offshore wind farms; ongoing studies explore aerial wind generation.

• Solar energy configurations range from traditional panels to concentrated solar power systems.

Hydroelectric and Thermal Power

• Hydroelectric plants can be reservoir-based or run-of-the-river; thermal plants may use coal, gas, or oil as fuel sources.

Analysis of Chile's Energy Generation

Historical Trends in Energy Production

• Reference to a source showing installed electric generation capacity in Chile with interactive data visualization.

• Historical data indicates a shift from hydraulic generation dominance towards increased coal usage since around 2014.

Growth of Renewable Energies

• Notable increase in non-conventional renewable energies (solar, wind, biomass, geothermal), reaching approximately 38.5% share in total generation by current year.

Challenges and Future Directions

Stability Concerns with Renewable Integration

• Transitioning fully to solar or wind poses stability challenges; reliance on hydroelectric or gas plants helps maintain voltage and frequency stability.

Solutions for Stability Enhancement

Energy Sources and Transmission Systems

Overview of Energy Capacities

• The discussion begins with an analysis of energy sources, focusing on their capacities measured in kilowatts rather than percentages. This approach provides a clearer understanding of the distribution among various energy types.

• There is a notable increase in unconventional renewable energies such as wind and solar power, alongside significant contributions from large hydroelectric plants. These sources help maintain grid stability as renewable energy usage expands.

Importance of Stability in Energy Networks

• Emphasis is placed on the necessity to enhance renewable energy while ensuring network stability; otherwise, increased installations could lead to grid failures.

Transmission and Distribution Systems

• The presentation transitions to transmission systems, showcasing various types including overhead lines and underground systems found in metro areas.

• An overview of Chile's electrical system structure reveals it was divided into four zones until 2017: Northern Interconnected System, Central Interconnected System, and smaller regions like Magallanes.

Changes Post 2017

• In November 2017, the Northern Interconnected System merged with the Central Interconnected System to form the National Electric System. By 2019, this system generated 77 thousand gigawatt-hours (GWh), with renewables accounting for approximately 44% of that total.

Geographic Scope and Characteristics

• The National Electric System spans over three thousand kilometers from north to south (Arica to Chiloé), presenting unique operational characteristics due to its length.

• A map illustrating this extensive system is referenced; it indicates voltage levels across transmission lines and identifies installed power plants by type (e.g., hydraulic or solar).

Visual Representation of Electrical Infrastructure

• Color-coded maps display different voltage values along transmission lines and highlight various power generation facilities distributed throughout the network.

Subtransmission Systems in Santiago

• Details about subtransmission systems are provided, showing how they connect different units within Santiago using transformers for voltage adjustments.

Types of Substations

• Various substations are discussed: some are outdoor installations while others are compact underground facilities designed for urban environments. These utilize insulating liquids instead of air for safety.

Understanding Electrical Systems and Their Evolution

Overview of Electrical Systems

• The discussion begins with a comparison of internal and external electrical systems, using the example of the Club Hípico station near the university.

• The location of the substation is highlighted, showing its proximity to Parque O'Higgins and marking it in relation to the university.

Historical Context: Edison vs. Tesla

• A historical overview is provided regarding Thomas Edison’s preference for direct current (DC), citing its better energy quality despite higher line losses.

• Nikola Tesla advocated for alternating current (AC), emphasizing its cost-effectiveness and ease of voltage transformation compared to DC.

Advantages of Alternating Current

• The importance of voltage levels is discussed; higher voltages reduce current, leading to lower energy losses during transmission.

• Using higher voltage allows for smaller cables, reducing material costs and enhancing system efficiency.

Transition to Three-Phase Systems

• The shift from single-phase to three-phase systems is explained; three-phase systems can transmit more power with fewer conductors.

• This transition not only reduces costs but also increases efficiency in electricity generation.

Future Directions: Hybrid Systems

• Modern advancements allow for hybrid systems that combine AC and DC, particularly beneficial for long-distance transmission.

• There’s an emphasis on renewable energy sources like solar power that operate directly with DC, influencing future system designs.

Standards and Safety in Electrical Wiring

• To differentiate between wires in a three-phase system, international standards are referenced; Chilean regulations specify color codes for phase identification.

• Proper adherence to these color codes is crucial for safety; misidentification can lead to dangerous connections.

Practical Application: Experimental Setup

• Students are instructed on documenting their wiring setups according to established color codes as part of their learning experience.

Representation of Electrical Waves

• The representation of electrical waves involves amplitude and phase angle adjustments based on connected loads.

Understanding Three-Phase Systems

Comparison of Complex and Real Components

• The discussion begins with a comparison between complex and real components, focusing on their representations in time versus factors. The time is represented as hours, while the factor is depicted as a constant amplitude vector rotating over time.

Phase Sequence and Voltage Representation

• As the sinusoidal wave increases, the factor rotates at a constant magnitude but changes its angle, maintaining synchronization with frequency. The phase sequence is defined positively based on the order of appearance of phases.

Writing Voltages in Phases

• Each voltage can be expressed concerning its phase angles: 0 degrees for one phase, -120 degrees for another, and +120 degrees for the last. This allows for clear representation of voltages across different phases.

Connection Types: Delta vs. Star

• Physical systems can connect in either delta or star configurations. In delta connections, phases are interconnected directly; in star connections, all phases converge at a common neutral point.

Current Relationships in Phases

• The current flowing through each phase is termed 'phase current,' while 'line current' refers to the total current circulating through the lines. Impedance relationships differ between star and delta configurations.

Balanced vs. Unbalanced Electrical Systems

Characteristics of Balanced Systems

• A balanced electrical system maintains equal loads across all phases, ensuring that generation and consumption are consistent. This results in stable voltage levels across each phase.

Diagrammatic Representation

• Balanced systems can be illustrated using unilinear diagrams that simplify representation by showing generators and loads without detailing every line or phase explicitly.

Impact of System Imbalance

• When systems become unbalanced due to faults like short circuits or varying load conditions, it disrupts equilibrium. Such imbalances necessitate adjustments to maintain zero-sum currents across phases.

Role of Neutral in Unbalanced Systems

• In an unbalanced system lacking a neutral connection, any discrepancies will affect other phases due to Kirchhoff's laws requiring net current to equal zero at junction points.

This structured approach provides clarity on key concepts related to three-phase electrical systems while allowing easy navigation through timestamps for further exploration of specific topics discussed within the transcript.

Understanding Power Measurement in Electrical Systems

Key Concepts of Power in Electrical Systems

• The discussion begins with the generation of potential difference between the generator and receiver, leading to the measurement of power in electrical systems.

• Power is described as complex, with apparent power calculated as voltage multiplied by the conjugate of current. This results in a complex value that can be separated into real (active power measured in kilowatts) and imaginary (reactive power measured in kilovars).

• The relationship between apparent power and active/reactive components is highlighted through the factor of power, which involves cosine and sine functions related to phase angles.

• The angle formed during these measurements indicates whether a system is inductive (angle > 0) or capacitive (angle < 0), which can be verified through laboratory experiments by connecting different loads.

Methods for Measuring Voltage

• Various methods exist for measuring voltage; one method mentioned is using "theorem of waves" or "34 meters," where connections are made from phases to neutral points.

• Another approach involves using "24 meters," selecting one phase as a common reference point for measurements between other phases, allowing total power calculation based on these readings.

Example Calculation: Delta Connection System

• An example illustrates a delta-connected load with balanced loads at specific angles. The phase transformation leads to calculations involving line-to-phase voltages and currents.

• Current per phase is calculated using voltage over load values, resulting in approximately 693 amperes per phase.

• Active power is computed using the formula involving voltage, current, and cosine of the angle (45 degrees), yielding an active power result that sums up across all phases due to system balance.

Further Calculations Using Different Measurement Techniques

• A second example reiterates similar calculations but employs different measurement techniques while maintaining consistent results across various setups.

• Emphasis on measuring line currents instead of phase currents highlights differences in methodology while still achieving accurate total power readings.