LIGHTNING ARRESTERS IN HIGH VOLTAGE ENGINEERING


  • The earthling screen and ground wires can well protect the electrical system against direct lightning strokes but they fail to provide protection against traveling waves which may reach the terminal apparatus. 
  • The lightning arresters or surge diverters provide protection against such surges.
  • A lightning arrester or a surge diverter is a protective device which conducts the high voltage surges on the power system to the ground.


  



  • Figure shows the basic form of a surge diverter. It consists of a spark gap in series with a non-linear resistor. One end of the diverter is connected to the terminal of the equipment to be protected and the other end is effectively grounded. 
  • The length of the gap is so set that normal line voltage is not enough to cause an arc across the gap but a dangerously high voltage will break down the air insulation and form an arc. 
  • The property of the non-linear resistance is that its resistance decreases as the voltage (or current) increases and vice-versa. This is clear from the volt/amp characteristic of the resistor shown in Figure. 
Action: The action of the lightning arrester or surge diverter is as under:

(i) Under normal operation, the lightning arrester is off the line i.e., it conducts r’ no current to earth or the gap is non-conducting.

(ii) On the occurrence of over voltage, the air insulation across the gap breaks down and an arc is formed, providing a low resistance path for the surge to the ground.
(iii) In this way, the excess charge on the line due to the surge is harmlessly conducted through the arrester to the ground instead of being sent back over the line.

(iv) It is worthwhile to mention the function of non-linear resistor in the operation of arrester. 

(v) As the gap sparks over due to over voltage, the arc would be a short circuit on the power system and may cause power-follow current in the arrester. 

Since the characteristic of the resistor is to offer high resistance to high voltage (or current), it prevents the effect of a short circuit. After the surge is over, the resistor offers high resistance to make the gap non-conducting.

  • Two things must be taken care of in the design of a lightning arrester. 
  • Firstly, when the surge is over, the arc in gap should cease. If the arc does not go out, the current would continue to flow through the resistor and both resistor and gap may be destroyed. 
  • Secondly, IR drop (where I is the surge current) across the arrester when carrying surge current should not exceed the breakdown strength of the insulation of the equipment to be protected.


1 comment:

Labels

PROJECTS 8086 PIN CONFIGURATION 80X86 PROCESSORS TRANSDUCERS 8086 – ARCHITECTURE Hall-Effect Transducers INTEL 8085 OPTICAL MATERIALS BIPOLAR TRANSISTORS INTEL 8255 Optoelectronic Devices Thermistors thevenin's theorem MAXIMUM MODE CONFIGURATION OF 8086 SYSTEM ASSEMBLY LANGUAGE PROGRAMME OF 80X86 PROCESSORS POWER PLANT ENGINEERING PRIME MOVERS 8279 with 8085 MINIMUM MODE CONFIGURATION OF 8086 SYSTEM MISCELLANEOUS DEVICES MODERN ENGINEERING MATERIALS 8085 Processor- Q and A-1 BASIC CONCEPTS OF FLUID MECHANICS OSCILLATORS 8085 Processor- Q and A-2 Features of 8086 PUMPS AND TURBINES 8031/8051 MICROCONTROLLER Chemfet Transducers DIODES FIRST LAW OF THERMODYNAMICS METHOD OF STATEMENTS 8279 with 8086 HIGH VOLTAGE ENGINEERING OVERVOLATGES AND INSULATION COORDINATION Thermocouples 8251A to 8086 ARCHITECTURE OF 8031/8051 Angle-Beam Transducers DATA TRANSFER INSTRUCTIONS IN 8051/8031 INSTRUCTION SET FOR 8051/8031 INTEL 8279 KEYBOARD AND DISPLAY INTERFACES USING 8279 LOGICAL INSTRUCTIONS FOR 8051/8031 Photonic Transducers TECHNOLOGICAL TIPS THREE POINT STARTER 8257 with 8085 ARITHMETIC INSTRUCTIONS IN 8051/8031 LIGHTNING PHENOMENA Photoelectric Detectors Physical Strain Gage Transducers 8259 PROCESSOR APPLICATIONS OF HALL EFFECT BRANCHING INSTRUCTIONS FOR 8051/8031 CPU OF 8031/8051 Capacitive Transducers DECODER Electromagnetic Transducer Hall voltage INTEL 8051 MICROCONTROLLER INTEL 8251A Insulation Resistance Test PINS AND SIGNALS OF 8031/8051 Physical Transducers Resistive Transducer STARTERS Thermocouple Vacuum Gages USART-INTEL 8251A APPLICATIONs OF 8085 MICROPROCESSOR CAPACITANCE Data Transfer Instructions In 8086 Processors EARTH FAULT RELAY ELECTRIC MOTORS ELECTRICAL AND ELECTRONIC INSTRUMENTS ELECTRICAL BREAKDOWN IN GASES FIELD EFFECT TRANSISTOR (FET) INTEL 8257 IONIZATION AND DECAY PROCESSES Inductive Transducers Microprocessor and Microcontroller OVER CURRENT RELAY OVER CURRENT RELAY TESTING METHODS PhotoConductive Detectors PhotoVoltaic Detectors Registers Of 8051/8031 Microcontroller Testing Methods ADC INTERFACE AMPLIFIERS APPLICATIONS OF 8259 EARTH ELECTRODE RESISTANCE MEASUREMENT TESTING METHODS EARTH FAULT RELAY TESTING METHODS Electricity Ferrodynamic Wattmeter Fiber-Optic Transducers IC TESTER IC TESTER part-2 INTERRUPTS Intravascular imaging transducer LIGHTNING ARRESTERS MEASUREMENT SYSTEM Mechanical imaging transducers Mesh Current-2 Millman's Theorem NEGATIVE FEEDBACK Norton's Polarity Test Potentiometric transducers Ratio Test SERIAL DATA COMMUNICATION SFR OF 8051/8031 SOLIDS AND LIQUIDS Speed Control System 8085 Stepper Motor Control System Winding Resistance Test 20 MVA 6-digits 6-digits 7-segment LEDs 7-segment A-to-D A/D ADC ADVANTAGES OF CORONA ALTERNATOR BY POTIER & ASA METHOD ANALOG TO DIGITAL CONVERTER AUXILIARY TRANSFORMER AUXILIARY TRANSFORMER TESTING AUXILIARY TRANSFORMER TESTING METHODS Analog Devices A–D BERNOULLI’S PRINCIPLE BUS BAR BUS BAR TESTING Basic measuring circuits Bernoulli's Equation Bit Manipulation Instruction Buchholz relay test CORONA POWER LOSS CURRENT TRANSFORMER CURRENT TRANSFORMER TESTING Contact resistance test Current to voltage converter DAC INTERFACE DESCRIBE MULTIPLY-EXCITED Digital Storage Oscilloscope Display Driver Circuit E PROMER ELPLUS NT-111 EPROM AND STATIC RAM EXCITED MAGNETIC FIELD Electrical Machines II- Exp NO.1 Energy Meters FACTORS AFFECTING CORONA FLIP FLOPS Fluid Dynamics and Bernoulli's Equation Fluorescence Chemical Transducers Foil Strain Gages HALL EFFECT HIGH VOLTAGE ENGG HV test HYSTERESIS MOTOR Hall co-efficient Hall voltage and Hall Co-efficient High Voltage Insulator Coating Hot-wire anemometer How to Read a Capacitor? IC TESTER part-1 INSTRUMENT TRANSFORMERS Importance of Hall Effect Insulation resistance check Insulator Coating Knee point Test LEDs LEDs Display Driver LEDs Display Driver Circuit LM35 LOGIC CONTROLLER LPT LPT PORT LPT PORT EXPANDER LPT PORT LPT PORT EXTENDER Life Gone? MAGNETIC FIELD MAGNETIC FIELD SYSTEMS METHOD OF STATEMENT FOR TRANSFORMER STABILITY TEST METHODS OF REDUCING CORONA EFFECT MULTIPLY-EXCITED MULTIPLY-EXCITED MAGNETIC FIELD SYSTEMS Mesh Current Mesh Current-1 Moving Iron Instruments Multiplexing Network Theorems Node Voltage Method On-No Load And On Load Condition PLC PORT EXTENDER POTIER & ASA METHOD POWER TRANSFORMER POWER TRANSFORMER TESTING POWER TRANSFORMER TESTING METHODS PROGRAMMABLE LOGIC PROGRAMMABLE LOGIC CONTROLLER Parallel Port EXPANDER Paschen's law Piezoelectric Wave-Propagation Transducers Potential Transformer RADIO INTERFERENCE RECTIFIERS REGULATION OF ALTERNATOR REGULATION OF THREE PHASE ALTERNATOR Read a Capacitor SINGLY-EXCITED SOLIDS AND LIQUIDS Classical gas laws Secondary effects Semiconductor strain gages Speaker Driver Strain Gages Streamer theory Superposition Superposition theorem Swinburne’s Test TMOD TRANSFORMER TESTING METHODS Tape Recorder Three-Phase Wattmeter Transformer Tap Changer Transformer Testing Vector group test Virus Activity Voltage Insulator Coating Voltage To Frequency Converter Voltage to current converter What is analog-to-digital conversion Windows work for Nokia capacitor labels excitation current test magnetic balance voltage to frequency converter wiki electronic frequency converter testing voltage with a multimeter 50 hz voltages voltmeter

Search More Posts

Followers