1. Fundamental HV Engineering
High Voltage (HV) Engineering is a critical field in electrical power systems, focusing on the behavior of electrical insulation materials under high voltage stress. The fundamentals of HV Engineering revolve around understanding dielectric behavior when subjected to various types of high voltages: AC, DC, and impulse[1].
Key aspects include:
Electric Field Strength: This is crucial in HV systems as it determines the stress on insulation materials[1].
Dielectric Materials:
- Gaseous Dielectrics: Understanding breakdown mechanisms in gases like air and SF6.
- Liquid Dielectrics: Behavior of insulating oils under high voltage stress.
- Solid Dielectrics: Properties and breakdown mechanisms in materials like polymers and ceramics[1].
Insulation Coordination: This involves selecting appropriate insulation levels for equipment to ensure reliable operation under various voltage conditions[11].
Overvoltage Protection: Understanding sources of overvoltages (lightning, switching) and designing protection systems[11].
2. Laboratory: HV Impulse Voltage Generation, Measurement and Testing
HV laboratories are essential for testing and validating equipment used in power systems. Key components include:
Impulse Voltage Generators: These simulate lightning and switching surges.
The Marx generator circuit is commonly used, consisting of capacitors charged in parallel and discharged in series[2].
Measurement Systems:
- Voltage dividers for accurate measurement of high voltages - Digital recording oscilloscopes for capturing waveforms - Sphere gaps for voltage calibration[2][4]
Testing Procedures:
- Lightning impulse tests (1.2/50 μs waveform) - Switching impulse tests (250/2500 μs waveform)
- Tests on various equipment like transformers, cables, and insulators[2]
Standards: Tests are conducted according to international standards like IEC 60060-1 for high voltage test techniques[4].
3. Basic EMC and Mitigation
Electromagnetic Compatibility (EMC) ensures that electrical and electronic systems can function correctly in their electromagnetic environment without causing interference to other equipment[5].
Key concepts include:
Electromagnetic Interference (EMI): Understanding sources and types of EMI (conducted, radiated)[5].
EMC Testing: Procedures to verify equipment compliance with EMC standards[5].
Mitigation Techniques:
- Shielding: Using conductive enclosures to block electromagnetic fields - Filtering: Employing low-pass filters to attenuate high-frequency noise - Grounding: Proper grounding techniques to minimize common-mode interference
- Cable routing and shielding to reduce coupling[5][6]
4. EMC Based External Lightning Protection System (LPS)
External LPS is designed to intercept direct lightning strikes and safely conduct the current to ground, protecting structures and occupants[7].
Key components:
Air-termination System: Designed to intercept lightning strikes, typically using rods, mesh conductors, or catenary wires[7].
Down-conductor System: Provides a low-impedance path from the air- termination to the earth-termination system[7].
Earth-termination System: Disperses the lightning current into the ground, minimizing potential differences[7].
Separation Distance: Ensures adequate isolation between the LPS and metallic parts of the structure[12].
5. EMC Based Internal Lightning Protection System
Internal LPS focuses on preventing dangerous sparking inside the structure due to lightning currents flowing in the external LPS or other conductive parts[12].
Key aspects:
Equipotential Bonding: Connecting all metallic systems to minimize potential differences[12].
Surge Protection Devices (SPDs): Installed at service entrances and critical equipment to divert surge currents and limit overvoltages[12].
Lightning Protection Zones (LPZ): Concept of dividing the structure into zones with different electromagnetic environments[7].
6. Arresters & Practical Work
Surge arresters are crucial components in HV systems for overvoltage protection[13].
Types of arresters:
- Distribution arresters - Station arresters
- Transmission line arresters (TLAs)[14]
Key characteristics:
- Maximum Continuous Operating Voltage (MCOV) - Energy handling capability
- Protective level (voltage-limiting performance)[13]
Practical work involves:
- Selection and sizing of arresters based on system voltage and expected surge levels
- Installation techniques to minimize lead lengths and ensure proper grounding - Testing and maintenance procedures to verify arrester performance[13][14]
Arrester applications:
- Substation equipment protection - Transmission line protection - Cable system protection
- Special applications like HVDC systems and series capacitor banks[15]
By understanding these fundamental aspects of HV engineering, EMC, lightning protection, and surge arresters, engineers can design and maintain reliable and safe high voltage power systems.
Citations:
[1] https://bharatsrajpurohit.weebly.com/high-voltage-engineering-course.html [2] https://www.mv.helsinki.fi/home/tpaulin/Text/hveng.pdf
[3] https://as-proceeding.com/index.php/icias/article/download/1462/1398/2706 [4] https://www.hvtechnologies.com/hv-equipment/impulse-testing/
[5] https://www.iec.ch/emc
[6] https://interferencetechnology.com/clocking-strategies-for-emi-reduction/
[7] https://library.e.abb.com/public/7d783b447aec5bc883257d1200429adc/
1TXH000196C0201-Helita%20external%20lightning%20protection.pdf
[8] https://www.obo.com.tr/fileadmin/DMS/Broschueren/02_TBS/Blitzschutz- Leitfaden_en.pdf
[9] https://www.inmr.com/technology-application-review-arresters-extend-life- cables/
[10]
https://community.ptc.com/sejnu66972/attachments/sejnu66972/PTCMathcad/
176416/1/3_3%20Application%20of%20Surge%20Arresters.pdf
[11] https://dbc.wroc.pl/Content/3458/PDF/high_voltage_engineering.pdf [12] https://www.dehn-international.com/sites/default/files/media/files/lpg- 2015-e-complete.pdf
[13] https://www.chintglobal.com/global/en/about-us/news-center/blog/how-do- high-voltage-surge-arresters-work.html
[14] https://www.nemaarresters.org/many-uses-transmission-line-arresters/
[15] https://www.hitachienergy.com/products-and-solutions/surge-arresters/
high-voltage-surge-arresters
