SURGE PROTECTION TECHNICAL BACKGROUND BASICS SURGE PROTECTION AGENDA
SURGE PROTECTION: TECHNICAL BACKGROUND & BASICS
SURGE PROTECTION – AGENDA ¾INTRODUCTION ¾AC POWER BASICS ¾POWER QUALITY SCOPE ¾VOLTAGE TRANSIENTS & DISTURBANCES ¾POWER QUALITY IN THE WORKPLACE & THEEFFECTS OF TRANSIENTS ¾MOV TECHNOLOGY &SURGE PROTECTIVE DEVICES 2 Name of the presentation - date
COURSE OBJECTIVES ¾DESCRIBE THE RISK THAT VOLTAGE SURGES POSE FOR TODAY’S ELECTRONIC EQUIPMENT ¾EXPLAIN THE BASICS OF AC POWER ¾EXPLAIN TYPES OF VOLTAGE DISTURBANCES ¾DISCUSS VARIOUS SURGE PROTECTION DEVICES 3 Name of the presentation - date
Overall Size Electronic Usage PROGRESSION OF ELECTRONIC DEVICES Time ¾USE OF ELECTRONIC EQUIPMENT HAS INCREASED ¾OVERALL SIZE OF THE EQUIPMENT HAS DECREASED ¾SMALLER MORE COMPACT ELECTRONIC DEVICES HAVE BECOME MORE SUSCEPTIBLE TO OVER-VOLTAGE FAILURES 4 Name of the presentation - date
MICROPROCESSOR ELECTRONICS ¾MICROPROCESSOR DRIVEN DEVICES CAN BE FOUND IN ALMOST EVERY COMMERCIAL, INDUSTRIAL AND RESIDENTIAL SETTING, FOR EXAMPLE: ¡Computer Networks, diagnostic equipment, alarm sensors, CNC machines, etc… ¾INTEGRATED CIRCUIT CHIPS ARE ESPECIALLY SENSITIVE TO TRANSIENT VOLTAGE SURGES DUE TO THEIR: ¡Microscopic size & structure ¡Extremely low operating voltages ¡Increased switching speeds 5 Name of the presentation - date
A PERSPECTIVE OF FACILITY DOWNTIME Average Length of Downtime per Incident Automotive Industry Chemical Steel & Aluminum 0 ¾FACILITY DOWNTIME COSTS COMMERCIAL AND INDUSTRIAL 20 40 Time (Minutes) 60 Average Cost/Hour Automotive Industry Chemical Steel & Aluminum 0. 0 6 Name of the presentation - date PLANTS NEARLY $26 BILLION A YEAR IN LOST TIME, EQUIPMENT REPAIR, AND REPLACEMENT 1. 0 2. 0 U. S. Dollars (Million)
AC POWER BASICS ¾NORTH AMERICAN POWER GENERATION FACILITIES SUPPLY ALTERNATING CURRENT (AC) POWER ¾AC FREQUENCY IS 60 CYCLES PER SECOND OR 60 HZ 7 Name of the presentation - date
WHAT IS A VOLTAGE SURGE? ¾HIGH AMPLITUDE, SHORT DURATION OVERVOLTAGE ¡Any voltage level that is short in duration and is also 10% greater than the systems normal operating AC, RMS or DC voltage level. ¡A voltage surge is also known as a voltage transient. 8 Name of the presentation - date
TYPES OF VOLTAGE DISTURBANCES ¾THE MOST COMMON VOLTAGE DISTURBANCE IS A SURGE OR SPIKE IN VOLTAGE ¾LESS COMMON TYPES OF DISTURBANCES ARE: ¡Swell – An increase in the power frequency AC voltage with durations from one half cycle to a few seconds ¡Sag – A rms reduction in the power frequency AC voltage with durations from one half cycle to a few seconds (also known as dip) 9 Name of the presentation - date Allen-Segal IBM Study
POWER QUALITY PROBLEMS Sources of Power Quality Problems in the Business Place Florida Power Study ¾ THERE ARE TWO GENERAL CAUSES OF VOLTAGE SURGE 1. Natural causes (lightning) 2. Other causes due to equipment or switching devices a. Utility switching b. Facility equipment due to switching in your facility, your neighbors facility or at the utility company 10 Name of the presentation - date
NATURAL CAUSES (LIGHTNING) Initial direct or indirect strike Travels through power lines or ground Enters your facility ¾DIRECT LIGHTNING STRIKES ¡Can be the most damaging ¾INDIRECT LIGHTNING STRIKES ¡Indirect lightning strikes up to 30 miles away can still affect your facility 11 Name of the presentation - date
CAUSES DUE TO EQUIPMENT SWITCHING Type 1: Utility Switching Utility Grid Switching Travels through power lines or ground Enters your facility Type 2: Facility generated Generated from within your facility Switching of large transformers, motors, and other inductive loads can generate spikes or transient impulses 12 Name of the presentation - date
HARMFUL EFFECTS OF TRANSIENT SURGES ¾THE MOST COMMON FAILURES PRODUCED BY TRANSIENTS WITHIN ELECTRONIC DEVICES ARE: ¡Disruptive effects – Encountered when a voltage transient enters an electronic component and the component then interprets the transient as a valid logic command, resulting in system lock-up, malfunctions, faulty output or corrupted files ¡Dissipative effects – Associated with short duration repetitive energy level surges, resulting in long-term degradation of the device ¡Destructive effects – Associated with high level energy surges, resulting in immediate equipment failure 13 Name of the presentation - date
SURGE PROTECTIVE DEVICE (SPD) ¾A SURGE PROTECTIVE DEVICE, ORSPD, REDUCES THE MAGNITUDE OF A VOLTAGE TRANSIENT SURGE THUS PROTECTING EQUIPMENT FROM DAMAGING EFFECTS. SPDS WERE COMMONLY KNOWN IN THE PAST AS TVSS (TRANSIENT VOLTAGE SURGE SUPPRESSOR) ¾A SPD TRIES TO: ¡Send surge away (to ground) ¡Acts as a momentary ‘short circuit’ ¡ ‘short circuit’ ≈ voltage equalization ≈ no overvoltage ≈ protected load 14 Name of the presentation - date
HOW A SPD WORKS Transient Voltage SPD Shunt Path ¾THE SPD ACTS AS A PRESSURE RELIEF VALVE ¾THE PRESSURE RELIEF VALVE (SPD) DOES NOTHING UNTIL AN OVER-PRESSURE PULSE (VOLTAGE SURGE)OCCURS IN THE WATER (POWER) SUPPLY 15 Name of the presentation - date
TERM TO KNOW: “CLAMPING” ¾CLAMPING DESCRIBES THE PROCESS BY WHICH AN SPD REDUCES VOLTAGE TRANSIENTS AND SURGES TO A SPECIFIED LOWER VOLTAGE LEVEL SUITABLE FOR THE PROTECTED LOAD Voltage Surge Residual Voltage (Let-Through Voltage) * Images from slides 6, 7 and 16 taken from Leviton Technical and Applications Module for Power Quality Products 16 Name of the presentation - date
TYPES OF SPD TECHNOLOGIES Metal Oxide Varistors (MOV) Silicon Junction Diode Spark Gap Gas Tube Arrestor Contains a ceramic mass of zinc oxide grains, combined with other metal oxides sandwiched between two metal plates forming a network of backto-back diode pairs The diode is installed reverse-biased under normal conditions. When the voltage rises above normal conditions the diode becomes forward-biased If a voltage surge is experienced a spark ignites gases creating an arc across the gap Commonly used for telephone lines as they enter a building Sophisticated spark gap that safely shunts the surge to ground 17 Name of the presentation - date
MOV TECHNOLOGY ¾CONTAINS A CERAMIC MASS OF ZINC OXIDE GRAINS COMBINED WITH SMALL QUANTITIES OF BISMUTH, COBALT AND MANGANESE SANDWICHED BETWEEN TWO METAL PLATES ¾THE BOUNDARY BETWEEN EACH GRAIN AND ITS NEIGHBOR FORMS A DIODE JUNCTION, ALLOWING CURRENT TO ONLY FLOW IN ONE DIRECTION ¾EQUIVALENT TO A MASS OF BACK-TOBACK DIODE PAIRS, EACH IN PARALLEL Schematic Symbols 18 Name of the presentation - date
MOV FAILURE MODES ¾ THERE ARE TWO TYPES OFMOV FAILURE MODES: 1. High energy over-voltages 2. Lower energy repetitive pulses 19 Name of the presentation - date
MOV FAILURE DUE TO HIGH ENERGY OVER VOLTAGES ¾ EVENT: LARGE SINGLE ENERGY EVENT SPIKE OR TRANSIENT BEYOND THE RATED CAPACITY OF THE DEVICE ¡Failure: Device will rupture or explode ¾ EVENT: SUSTAINED OVER-VOLTAGE CONDITION BUILDING UP ENERGY Due to the destructive nature of this failure surge rated fuses are required for all MOV installations. (Except TPMOV®) Every time an MOV switches, its life is slightly degraded. The greater the transient hit, the greater the degradation of the MOV 20 Name of the presentation - date ¡Failure: Device will go into thermal overheating and rupture (thermal overload) ¾ EVENT: REPEATED LOWER LEVEL SPIKES OR TRANSIENT OVERVOLTAGE CONDITIONS ¡Failure: Device will slowly degrade until failure
CONTACT MERSEN FOR SURGE PROTECTION SOLUTIONS &PRODUCTS ¾EMAIL: INFO. NBY@MERSEN. COM ¾CALL: 978 -462 -6662 ¾WEB: EP. MERSEN. COM 21 Name of the presentation - date
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