This document discusses high voltage direct current (HVDC) electric power transmission. It provides an introduction to HVDC, outlines its history including the first HVDC transmission systems in Sweden and India. It describes the components used in HVDC including converter stations, rectifiers, filters and inverters. It discusses reasons for using HVDC over HVAC such as lower transmission losses and costs. Limitations of HVDC include costly terminal equipment and complex control systems. Applications include long distance and asynchronous transmission. The future may include fully converting generation to distribution systems to direct current.
HVDC (high-voltage direct current) is a highly efficient alternative for transmitting large amounts of electricity over long distances and for special purpose applications.
Applications of power electronics in HVDCKabilesh K
Role of Power electronics in HVDC and Transmission system. What are the components of Power electronics used in HVDC. Types of HVDC Links. Advantages of HVDC over HVAC.
Introduction, Operation of 12-pulse converter as receiving and sending terminals of HVDC system, Equipment required for HVDC System and their significance, Comparison of AC and DC transmission, Control of HVDC transmission
HVDC (high-voltage direct current) is a highly efficient alternative for transmitting large amounts of electricity over long distances and for special purpose applications.
Applications of power electronics in HVDCKabilesh K
Role of Power electronics in HVDC and Transmission system. What are the components of Power electronics used in HVDC. Types of HVDC Links. Advantages of HVDC over HVAC.
Introduction, Operation of 12-pulse converter as receiving and sending terminals of HVDC system, Equipment required for HVDC System and their significance, Comparison of AC and DC transmission, Control of HVDC transmission
High Voltage Direct Current Transmission SystemNadeem Khilji
The development of HVDC (High Voltage Direct Current) transmission system dates back to the 1930s when mercury arc rectifiers were invented. Since the 1960s, HVDC transmission system is now a mature technology and has played a vital part in both long distance transmission and in the interconnection of systems. Transmitting power at high voltage and in DC form instead of AC is a new technology proven to be economic and simple in operation which is HVDC transmission. HVDC transmission systems, when installed, often form the backbone of an electric power system. They combine high reliability with a long useful life. An HVDC link avoids some of the disadvantages and limitations of AC transmission. HVDC transmission refers to that the AC power generated at a power plant is transformed into DC power before its transmission. At the inverter (receiving side), it is then transformed back into its original AC power and then supplied to each household. Such power transmission method makes it possible to transmit electric power in an economic way.
High Voltage Direct Current technology has certain characteristics which
make it especially attractive for transmission system applications. HVDC
transmission system is useful for long-distance transmission, bulk power delivery and
long submarine cable crossings and asynchronous interconnections. The study of
faults is essential for reasonable protection design because the faults will induce a
significant influence on operation of HVDC transmission system. This paper provides
the most dominant and frequent faults on the HVDC systems such as DC Line-to-
Ground fault and Line-to-Line fault on DC link and some common types of AC faults
occurs in overhead transmission system such as Line-to-Ground fault, Line-to-Line
fault and L-L-L fault. In HVDC system, faults on rectifier side or inverter side have
major affects on system stability. The various types of faults are considered in the
HVDC system which causes due to malfunctions of valves and controllers, misfire
and short circuit across the inverter station, flashover and three phase short circuit.
The various faults occurs at the converter station of a HVDC system and
Controlling action for those faults. Most of the studies have been conducted on line
faults. But faults on rectifier or inverter side of a HVDC system have great impact on
system stability. Faults considered are fire-through, misfire, and short circuit across
the inverter station, flashover, and a three-phase short circuit in the ac system. These
investigations are studied using matlab simulink models and the result represented in
the form of typical time responses.
HVDC Bridge and Station Configurations
1. General HVDC – HVAC Comparisons
2. Components of a Converter Bridge
3. HVDC scheme configurations
Operation of the HVDC converter
1. General assumptions
2. Rectifier operation with uncontrolled valves and X = 0
3. Rectifier operation with controlled valves and X = 0
4. Rectifier operation with controlled valves and X 0
5. Inverter operation with controlled valves and X 0
6. Commutation and Commutation Failure
7. Reactive Power Requirements
8. Short-circuit capacity requirements for an HVDC terminal.
9. Harmonics and filtering on the AC and DC sides
High Voltage Direct Current Transmission SystemNadeem Khilji
The development of HVDC (High Voltage Direct Current) transmission system dates back to the 1930s when mercury arc rectifiers were invented. Since the 1960s, HVDC transmission system is now a mature technology and has played a vital part in both long distance transmission and in the interconnection of systems. Transmitting power at high voltage and in DC form instead of AC is a new technology proven to be economic and simple in operation which is HVDC transmission. HVDC transmission systems, when installed, often form the backbone of an electric power system. They combine high reliability with a long useful life. An HVDC link avoids some of the disadvantages and limitations of AC transmission. HVDC transmission refers to that the AC power generated at a power plant is transformed into DC power before its transmission. At the inverter (receiving side), it is then transformed back into its original AC power and then supplied to each household. Such power transmission method makes it possible to transmit electric power in an economic way.
High Voltage Direct Current technology has certain characteristics which
make it especially attractive for transmission system applications. HVDC
transmission system is useful for long-distance transmission, bulk power delivery and
long submarine cable crossings and asynchronous interconnections. The study of
faults is essential for reasonable protection design because the faults will induce a
significant influence on operation of HVDC transmission system. This paper provides
the most dominant and frequent faults on the HVDC systems such as DC Line-to-
Ground fault and Line-to-Line fault on DC link and some common types of AC faults
occurs in overhead transmission system such as Line-to-Ground fault, Line-to-Line
fault and L-L-L fault. In HVDC system, faults on rectifier side or inverter side have
major affects on system stability. The various types of faults are considered in the
HVDC system which causes due to malfunctions of valves and controllers, misfire
and short circuit across the inverter station, flashover and three phase short circuit.
The various faults occurs at the converter station of a HVDC system and
Controlling action for those faults. Most of the studies have been conducted on line
faults. But faults on rectifier or inverter side of a HVDC system have great impact on
system stability. Faults considered are fire-through, misfire, and short circuit across
the inverter station, flashover, and a three-phase short circuit in the ac system. These
investigations are studied using matlab simulink models and the result represented in
the form of typical time responses.
HVDC Bridge and Station Configurations
1. General HVDC – HVAC Comparisons
2. Components of a Converter Bridge
3. HVDC scheme configurations
Operation of the HVDC converter
1. General assumptions
2. Rectifier operation with uncontrolled valves and X = 0
3. Rectifier operation with controlled valves and X = 0
4. Rectifier operation with controlled valves and X 0
5. Inverter operation with controlled valves and X 0
6. Commutation and Commutation Failure
7. Reactive Power Requirements
8. Short-circuit capacity requirements for an HVDC terminal.
9. Harmonics and filtering on the AC and DC sides
The Solar System[c] is the gravitationally bound system of the Sun and the objects that orbit it. The largest of such objects are the eight planets, in order from the Sun: four terrestrial planets named Mercury, Venus, Earth and Mars, two gas giants named Jupiter and Saturn, and two ice giants named Uranus and Neptune. The terrestrial planets have a definite surface and are mostly made of rock and metal. The gas giants are mostly made of hydrogen and helium, while the ice giants are mostly made of 'volatile' substances such as water, ammonia, and methane. In some texts, these terrestrial and giant planets are called the inner Solar System and outer Solar System planets respectively.
Alternating current (AC) is the main driving force in the industries and residential areas, but for the long transmission line (more than 650 KM) AC transmission is more expensive than that of direct current (DC). Technically, AC transmission line control is more complicated because of the frequency. DC transmission does not have these limitations, which has led to build long HVDC transmission lines over the last 40 years. HVDC technology made possible to transfer bulk power over long distances.
High Voltage Direct Current Transmission System ReportNadeem Khilji
The development of HVDC (High Voltage Direct Current) transmission system dates back to the 1930s when mercury arc rectifiers were invented. Since the 1960s, HVDC transmission system is now a mature technology and has played a vital part in both long distance transmission and in the interconnection of systems. Transmitting power at high voltage and in DC form instead of AC is a new technology proven to be economic and simple in operation which is HVDC transmission. HVDC transmission systems, when installed, often form the backbone of an electric power system. They combine high reliability with a long useful life. An HVDC link avoids some of the disadvantages and limitations of AC transmission. HVDC transmission refers to that the AC power generated at a power plant is transformed into DC power before its transmission. At the inverter (receiving side), it is then transformed back into its original AC power and then supplied to each household. Such power transmission method makes it possible to transmit electric power in an economic way.
Introduction, equipment required for HVDC systems, Comparison of AC and DC Transmission, Limitations of HVDC transmission lines, reliability of HVDC systems, comparison of HVDC link with EHVAC link, HVDC system configuration and components, fundamental equations in HVDC system, HVDC links, converter theory and performance equation, valve characteristic, converter circuits, converter transformer testing, multi bridge converters, abnormal operation of HVDC system, control of HVDC system, harmonics and filters. Influence of AC system strength on AC/DC system interaction, response to AC and DC system faults, Concept of reactive power compensation- reactive Power balance in HVDC substations-Effect of angle of advance and extinction angle on reactive power requirement of converters.
An electric vehicle (EV) is one that operates on an electric motor, instead of an internal-combustion engine that generates power by burning a mix of fuel and gases. Therefore, such as vehicle is seen as a possible replacement for current-generation automobile, in order to address the issue of rising pollution, global warming, depleting natural resources, etc. Though the concept of electric vehicles has been around for a long time, it has drawn a considerable amount of interest in the past decade amid a rising carbon footprint and other environmental impacts of fuel-based vehicles.
The Vindhyachal Thermal Power Station is located in Singrauli district in the Indian state of Madhya Pradesh. One of the coal-fired power stations of NTPC, it is the largest power station in India, with an installed capacity of 4,760 MW. The coal for the power plant is sourced from Nigahi mines, and the water is sourced from the discharge canal of Singrauli Super Thermal Power Station
We had made a working model on static VAR compensator which is made by power electronic switch and mechanically switched. We had chosen mechanically switched capacitor method to improved receiving end voltage as well as power factor.
The topic contains some electrical basic law and terminology Ohm's Law, KVL & KCL, Voltage and Current Division Rule, Faraday Laws of electromagnetic Induction and Lenz Law
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
How to Split Bills in the Odoo 17 POS ModuleCeline George
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We all have good and bad thoughts from time to time and situation to situation. We are bombarded daily with spiraling thoughts(both negative and positive) creating all-consuming feel , making us difficult to manage with associated suffering. Good thoughts are like our Mob Signal (Positive thought) amidst noise(negative thought) in the atmosphere. Negative thoughts like noise outweigh positive thoughts. These thoughts often create unwanted confusion, trouble, stress and frustration in our mind as well as chaos in our physical world. Negative thoughts are also known as “distorted thinking”.
Students, digital devices and success - Andreas Schleicher - 27 May 2024..pptxEduSkills OECD
Andreas Schleicher presents at the OECD webinar ‘Digital devices in schools: detrimental distraction or secret to success?’ on 27 May 2024. The presentation was based on findings from PISA 2022 results and the webinar helped launch the PISA in Focus ‘Managing screen time: How to protect and equip students against distraction’ https://www.oecd-ilibrary.org/education/managing-screen-time_7c225af4-en and the OECD Education Policy Perspective ‘Students, digital devices and success’ can be found here - https://oe.cd/il/5yV
1. Presented by: Guided by:
Vinay Vishwakarma Er. Gaurav Kumar Mishra
Yogesh Mishra Head of Electrical Engg.
Devesh Pandey
Ashish Tiwari
Ravi Mishra
Amit Shukla
Department Of Electrical Engineering
6th Semester
2.
3. 1. INTRODUCTION
2. HISTORY OF HVDC
3. PROCESS DIAGRAM
4. THE LINK BETWEEN RIHAND TO DADRI
SUBSTATION
5. COMPONENT USED
6. WHY HVDC IS NECESSARY OVER AC
7. LIMITATION OF HVDC
8. APPLICATION OF HVDC
9. THE FUTURE PROSPECTS
10. CONCLUSION
4. • A high-voltage, direct current (HVDC) electric power
transmission system uses direct current for the bulk
transmission of electrical power.
• For long-distance transmission, HVDC systems may be less
expensive and suffer lower electrical losses.
• High voltage is used for electric power transmission to reduce
the energy lost in the resistance of the wires.
• Recent developments in conversion equipment have reduced
their size and cost and improved their reliability.
• The major components of a HVDC transmission system are
converter stations where conversion from AC to DC and from
DC to AC are performed.
5. • Firstly HVDC between Swedish and Gotland in 1954.
• In North America, total HVDC transmission capacity in
1987 was 14,000MW.
• First HVDC is commissioned in India in 1990 at Rihand to
Dadri(near Delhi).
• Distance between stations is 814 km.
• It transfer the power at ±500 KV and 1500 MW.
6.
7. 6V/12V---12V AC to 12V DC—transmission– 12V DC to 12V AC---
12V/6V– sub transmission– 6V/3V--- distribution and lightning.
8. • Converter Transformer
Step up Transformer ( at Generation Station).
Step up Transformer (at Substation).
Step down Transformer (at Distribution).
• Rectifier is a static device which converts AC into Pulsating
DC voltage.
• Filter is used to make the ripple free supply (pure DC).
• Invertor is a static device which converts DC into AC voltage
with desired frequency.
• Power LEDs is used for lightning a plant.
9. The reasons for selecting HVDC instead of HVAC are :-
1. Lower cost at operating condition.
2. Lower transmission losses.
• As only two conductor are required in HVDC hence I2R losses are
low for same power transfer.
3. Cheaper in cost.
• Require two wire for transmission but AC needs Three wire.
• Size of Pole, Insulators, Cross Arm are to be reduced.
• The phase to phase clearance, phase to ground clearance and tower size
are smaller in case of DC transmission.
4. Asynchronous interconnections.
• A DC link can be used to inter-connect two AC systems of different
frequency.
10. 6. No Skin effect:
There is no skin effect in DC, because skin effect is directly
proportion to frequency and hence there is uniform distribution of
current over the cross-section of the conductor.
7. Better voltage regulation.
• Because there is no inductance and capacitance therefore voltage
regulation is 0%.
7. Absence of charging current.
8. Low short circuit currents.
9. Direct Current saves forest and lands.
13. 1. Costly terminal equipments.
• The convertors required at both the ends are more
expensive.
• The convertors produce a lot of harmonics both on DC and
AC sides and may cause Radio Interference.
• To remove ripples from the DC output, filtering &
smoothening equipments are to be provided.
2. More maintenance of insulators is required in HVDC
system.
3. Complexity of control.
4. Voltage transformation is not easier in case of DC system.
14. 1. For long distance high power transmission.
2. For interconnection (tie lines) between two or more AC
systems having their own load frequency control.
3. For back to back asynchronous tie substation where two AC
systems are interconnected by a convertor substation without
any AC transmission line in between.
4. For underground or submarine cable transmission over long
distances at high voltage.
15. There are the following future aspects of the project as:
1. The complete system from generation to distribution is in the
from of DC i.e. possible by using power electronics circuits.
2. By using DC Choppers in place of transformers, we have
resolved complete system into DC system.
16. • Availability of non- renewable resources is limited.
• HVDC is used for increasing the efficiency of transmission
lines.
• Dependency of source from foreign countries are to be reduced.
• HVDC transmission line gives the Reliable, Economical and
Stable supply as compares to AC.
