Title: Teaching Utility Applications of Power Electronics in a First Course on Power Systems
1Teaching Utility Applications of Power
Electronics in a First Course on Power Systems
2Outline
- Importance of teaching power electronics in a
power systems course - Description of proposed approach consisting of
four segments - Functional aspects of power electronics
- Power device capabilities and Power Electronic
Structures - Role of power electronics in utility applications
- Details of the power electronics structures
3Importance
- Increasing applications of Power Electronic
Equipment in Power Systems - Availability of high power semiconductor devices
- Decentralized renewable energy generation
sources - Increased power transfer with existing
transmissionsystem - Effective control of power flow needed in a
deregulated environment - Norms for Power quality
Future Power System
4Approach
- Top Down approach consisting of four segments
- Function of power electronics as an interface,
and the listing of utility applications requiring
power electronics interface (1 lecture) - Power device capabilities and the resulting
structures of power electronic interfaces to
exploit them (1 lecture) - Importance and the role of power electronic
interfaces in various applications (2 lectures) - Discussion of power electronics interface in
appropriate detail (3 lectures)
5Segment 1 Function of Power Electronics in
Utility Applications
- Enabling technology providing interface between
two (ac/dc) electrical systems - E.g.
- Interconnection of two asynchronous ac systems
- dc to ac conversion is required to connect fuel
cells or photovoltaics to the utility grid
6Segment 1 Listing of Power Electronic
Applications
- Distributed generation (DG)
- Renewable resources (wind and photovoltaic)
- Fuel cells and micro-turbines
- Storage batteries, super-conducting magnetic
energy storage, flywheels - Power electronics loads Adjustable speed drives
- Power quality solutions
- Dual feeders
- Uninterruptible power supplies
- Dynamic voltage restorers
- Transmission and distribution (TD)
- High voltage dc (HVDC) and medium voltage dc
- Flexible AC Transmission Systems (FACTS) Shunt
and Series compensation, and the unified power
flow controller
7Segment 2 Power Device Capabilities Resulting
Power Electronic Structures
- Power Semiconductor Devices and their
Capabilities - Polarity of voltage blocked and direction of
current conduction - Switching speeds and power ratings
8Segment 2 Structure of Power Electronic Systems
- Voltage-Link Systems
- Transistors and diodes that can block voltage of
only one polarity - Current-Link Systems
- higher power bipolar voltage-blocking
capabilities of thyristors - Solid State Switches
- bidirectional voltage blockingand current
conduction
9Segment 3 Role of Power Electronics in Important
Utility Applications
- Distributed Generation (DG) ApplicationsPower
electronic interface depends on the source
characteristics
Wind Power Generation with Doubly Fed Induction
Motors
Photo-voltaics Interface
(c)
10Segment 3 Role of Power Electronics in Important
Utility Applications
- Power Electronic Loads Adjustable Speed Drives
(c)
11Segment 3 Role of Power Electronics in Important
Utility Applications
- Power Quality Solutions for
- voltage distortion
- unbalances
- voltage sags and swells
- power outages
(c)
12Segment 3 Role of Power Electronics in Important
Utility Applications
- Transmission and Distribution DC Transmission
- most flexible solution for connection of two ac
systems
13Segment 3 Role of Power Electronics in Important
Utility Applications
- Transmission and Distribution Flexible AC
Transmission Systems (FACTS)
14Segment 4 Discussion of Power Electronics
Interface
- Fundamental concepts for understanding the
operation of the power electronic structures - voltage-link systems
- current link systems
- solid state switches
15Voltage-Link Systems
- Unifying approach Power-Pole Building Block
- building block of all voltage-link systems
16Voltage-Link Systems
- Power conversion using Pulse Width Modulation
(PWM) - Power reversal with reversal of current direction
- Averaged conversion
17Voltage-Link Systems
- Averaged Representation of Power Pole
- Average quantities are of main interest
18Voltage-Link Systems
- Synthesis of AC voltages
- voltage to be synthesized
- duty ratio needed
- dc side current
19Voltage-Link Systems
- Implementation of bi-positional switch
(d)
20Current-Link Systems
- Exclusively thyristor based
- One of (T1, T2, T3) and (T2, T4, T6)conduct at a
time - Average dc voltage controlled by firing angle
- Power flow reversed by reversing voltage polarity
(d)
21Solid State Switch
- Can conduct current in both directions
- Turn-on or off in an ac circuit in one-half of a
line-frequency cycle
(d)
22Conclusion
- Teaching utility applications of power
electronics in a power systems course is very
important - A top down approach, starting with functional
aspects and going to implementation details is
suggested - Topics outlined in the four segment proposed
structure will introduce students to future
practices and technologies in power engineering - The proposed structure may be adapted based on
individual preferences