EE4503 Electrical Systems Design Electrical Equipment and Apparatus

Topics Introduction to Electrical Equipment and Apparatus Medium Voltage Equipment Low Voltage Equipment

Equipment Degree of Protection Level: IP IPxy or IPxyz: IP follow by two or three digit number x: level of protection against contact or solid material getting into y: level of protection against liquid z: level of protection against impact

Equipment Degree of Protection Level: IP http://www.apemswitches.be/1-26428-General-information.php

Electrical Equipment and Apparatus HV Equipment (High Voltage): more than 36kV MV Equipment (Medium Voltage): 1kV to 36kV LV Equipment (Low Voltage): less than 1kV

Electrical Equipment and Apparatus MV Equipment

MV Equipment http://www.geelectrical.com/catalog/buylog/15_BL.pdf Surge Arrestor Current Transformer / Potential Transformer Power Meter 50/51 Relay (instantaneous overcurrent relay and ac inverse time over current relay) Circuit Breaker (IEEE 52) Disconnecting Switches / Load Interrupter Switches Fuses http://www.geelectrical.com/catalog/buylog/15_BL.pdf

Electrical Systems Design: ประสิทธิ์ พิทยพัฒน์ MV Equipment Electrical Systems Design: ประสิทธิ์ พิทยพัฒน์

MV Equipment Lightning Arrester: LA Operation Normal: High Impedance so low Leakage Current Overvoltage: Impedance Drop so Lightning Current goes to ground Type: Spark Gap Arrester & Arrester without Spark Gap Rating: Voltage and Discharge Current

MV Equipment LA: Spark Gap Arrester Old type, less uses Components: Spark Gap Varistor SiC-Arrester Varistor is the resistor with nonlinear behavior between resistant and voltage SiC (Silicon Carbine) http://c03.apogee.net/contentplayer/?coursetype=foe&utilityid=northwestern&id=4486

MV Equipment LA: Arrester Without Spark Gap Components: Strong Non-linear Voltage dependent e.g Zinc Oxide MO-Arrester ZnO-Arrester MO = Metal Oxide FRP = Fiberglass Reinforced Plastics http://zone4info.com/articles/401/constructive-design-of-mo-arresters

MV Equipment Disconnector or Disconnecting Switch (DS) Use to disconnect the circuit Disconnect high voltage but low (or no) current circuit If on-load disconnection, require Load Buster Create large isolating distance for safety ** For safety, interlocks with other devices

MV Equipment Disconnector or Disconnecting Switch (DS) Manual Operated, Motor Operated, or Pneumatic Drive Rating: Rated Voltage, Rated Normal Current, Short Circuit Current, BIL BIL = Basic (lightning) Impulse Insulation Level

MV Equipment Earthing Switches: ES Connect the metal parts to ground discharging extra charge that left in the circuit. for the safety when maintain the system. May interlock with other devices e.g. DS Rating: Rated Voltage, Short Circuit Current, BIL

MV Equipment High Voltage High Rupturing Capacity Fuses: HV HRC Fuses Protect the electrical system from over- current or short-circuit. Compose of fuse string and material to suppress arcs. Some have a “Striker Pin” to indicate the disconnecting.

MV Equipment High Voltage High Rupturing Capacity Fuses: HV HRC Fuses Rating: Maximum Operating Voltage Rating, Continuous Current Rating, Short Circuit Current Rating, Selectivity (cooperate more than one safety devices together) Special Rating for using with motor: Starting Current & Starting Time

MV Equipment Switch Disconnector or Load Break Switch: SD Able to disconnect circuit at load current Contain Arc Suppression Create large isolating distance for safety Rating: BIL, Rated Voltage, Rated Operating Current, Rated Breaking Current, Rated Short Circuit Making Current

MV Equipment SD Arc Suppression Operated by Spring Air Vacuum Gas (e.g. SF6) Operated by Spring http://www.accessscience.com/search.aspx?rootID=792429

MV Equipment Instrument Transformer Voltage Transformer Current Transformer http://4hv.org/print.php?plugin:forum.134619

MV Equipment Voltage Transformers Transform the high voltage to the measurable voltage level Do not SHORT circuit the secondary coil Rating: Burden, Primary Voltage, Secondary Voltage, Permissible Voltage Stress, Accuracy Measurement: Class 0.1 = 0.1%, Class 0.5 = 0.5% Protection: Class 3P = 3%, Class 6P = 6% Burden is the about of power that still give the valid reading (exceptable at 25% or 100% of burden) Permissible Voltage Stress is the factor of the voltage that VT can still be usable for example, 1.2

MV Equipment Current Transformers Transform the high current to the measurable current level (usually 5A) Do not OPEN circuit the secondary coil Some have “OPEN-circuit” protection Rating: Burden, Primary Current, Secondary Current, Short-circuit Current, Rated Voltage, Accuracy Class

MV Equipment Current Transformers Sometime have two secondary core: protection & measuring cores. Measuring Core: small saturation factor Accuracy: Class 0.1 = 0.1%, Class 0.5 = 0.5% Measuring Core: high saturation factor Accuracy: Class 5P = 5%, Class 10P = 10% Accuracy: Class 5P10 = 5% at 10 time rated current

MV Equipment Protective Relay Detect the event and signal circuit breaker. Usually need CT & VT Mechanism Electromechanical Relays Solid State Relays Digital Relays

MV Equipment Protective Relay Overcurrent Relay (50, 51) Ground Fault Relay (50N, 51N) Directional Overcurrent Relay (67) Directional Ground Fault Relay (67N) Directional Power Relay (32) Distance Relay (21) Differential Relay (87) Under Voltage Relay (27)

MV Equipment MV Circuit Breaker: MVCB MVCB is able to break the circuit in the normal load and in the short circuit condition. MVCB take the order from specific relays to trip.

MV Equipment MV Circuit Breaker: MVCB Need to suppress arcs: Vaccum SF6 Rating: Voltage, BIL, Nominal Current, Short Circuit Current

MV Equipment MV Contactors Switch that use for the situation where a lot of open/close circuit happen: e.g. Motor circuit

MV Equipment MV Switchgears Complete set of switching devices, protection devices, measurement devices. Use at the incoming of the power system and distribute out on the other side

MV Equipment MV Switchgears Enclosure Busbar Protection Devices Measurement Devices http://www.daidongs.com/eng/high-voltage-switchgear.htm

MV Equipment MV Switchgears Cubicle Compartmented Metal - Clad http://metechakir.blogspot.com/2012/05/metal-clad-switchgear-power-systems.html

MV Equipment Ring Main Unit: RMU Like Switchgear Like Selector Switch http://www.t.optimumalelektrik.com/ring-main-unit-teknik-cizimleri.html

MV Equipment Transformer Bridge to Low Voltage system Categorized by insulator & heat ventilation Liquid-immersed Transformer Oil-type Transformer Less-Flammable Liquid-insulated Transformer Dry-Type Transformer

MV Equipment Transformer Usually contain over-heat protection Sensors: 3 levels (start ventilation, warning, shutdown) Temperature-Relay Protective Enclosure (even dry type) Cast Resin Transformer: can overload by 30-40% using extra heat ventilation

Electrical Equipment and Apparatus LV Equipment

LV Equipment Circuit Breaker switch and able to disconnect circuit when there is overload or short-circuit Two main types: Molded Case Circuit Breaker (MCCB) Air Circuit Breaker (ACB) Rating: Continuous Current, Interrupting Capacity

LV Equipment Circuit Breaker - MCCB MCCB is made of strong polymer material. Miniature Circuit Breaker (MCB) used in the consumer unit: 1, 2 or 3 poles for IC around 3kA to 10kA. Earth Leakage Circuit Breaker (ELCB) or Residual Current Circuit Breaker: 10mA or 30mA

LV Equipment Circuit Breaker - MCCB Standard CB: usually around 100AF to 2,500AF and the IC is around 18kA to 30kA High Interrupting Capacity Circuit Breaker: Used when there is a chance of high short-circuit current. IC is usually very high 25kA to 100kA. Current Limiting Circuit Breaker: Used for very fast breaking and very high short-circuit current

LV Equipment Circuit Breaker - ACB Usually large circuit breakers Two types: Fixed Type Drawout

LV Equipment Circuit Breaker – ACB v.s. MCCB ACB’s components can be accessed MCB is required no maintenance ACB is suitable for large systems when the short circuit current is high http://www.everfarelec.com/index.php/product/Air%20Circuit%20Breaker.html

LV Equipment Circuit Breaker – Continuous Current The amount of current that can pass thru the CB under the given ambient temperature Usually manufactures usually offer one frame with many rating: Ampere Frame (AF): maximum rating for the specified structure Ampere Trip (AT): selected rating for each CB

LV Equipment Circuit Breaker – Interrupting Capacity Interrupting Capacity (IC) or Breaking Capacity is the maximum short-circuit current that the CB is still functional. IC has to be tested under many parameters, e.g. voltage, power factor, harmonics, etc.

LV Equipment Circuit Breaker – Tripping Unit The main function of the CB is to properly trip the system Thermal – Magnetic Solid State Trip

LV Equipment Circuit Breaker – Thermal & Magnetic Trip Thermal (Bimetal) Device: Small Overload about 125% of rated current & Long Time Delay Electromagnetic Device: Large Overload about 10 times of rated current & Instantaneous Trip Time

LV Equipment Circuit Breaker – Thermal & Magnetic Trip Electrical Systems Design: ประสิทธิ์ พิทยพัฒน์

LV Equipment Circuit Breaker – Thermal & Magnetic Trip http://electrical-engineering-portal.com/how-circuit-breaker-trip-unit-works

LV Equipment Circuit Breaker – Thermal & Magnetic Trip http://electrical-engineering-portal.com/how-circuit-breaker-trip-unit-works

LV Equipment Circuit Breaker – Thermal & Magnetic Trip http://electrical-engineering-portal.com/how-circuit-breaker-trip-unit-works

LV Equipment Circuit Breaker – Solid State Trip Use electronics to decide the trip action High accuracy and reliability Can be configuration tripping pattern in many ways

LV Equipment Low Voltage Fuses Breaking the circuit by melting the metal when over current. D-fuse D0-fuse NH (HRC) fuse (usually in industries) Rating: Nominal Current, Nominal Voltage, Short-circuit Current

LV Equipment Low Voltage Fuses – D & D0 Fuse http://www.galco.com/techdoc/brsh/10d27r_dat.pdf

LV Equipment Low Voltage Fuses – HRC Fuse Many sizes (dimensions) Rated current from 6A to 1,250A Short-circuit current up to 100kA http://www.hausmanngroup.de/ip/fuses.pdf

LV Equipment Panelboards The equipment that takes the main power in and distributes power out to many feeder. http://www.automatech.co.uk/products/moeller.asp?scid=18&gpcid=1&cid=4

LV Equipment Panelboards - components Enclosures to protect the inside components Busbars conducts the current to Branch CB and also hold the CB Circuit Breakers Main CB Branch CB: Plug-in unit

LV Equipment Panelboards – consumer units IC is about 10kA Single phase 4, 6, 8, 12, 16 branches Main CB: AT=16, 20, 32, 45, 63, 70, 80, 110A Three phases 12, 18, 24, 30, 36, 42 branches

LV Equipment Panelboards – industrial units Three phases 12, 18, 24, 30, 36, 42 branches Usually being used as “Load Center” Main Lugs: is mainly for distributing load Main Circuit Breaker: complete with main circuit breaker

LV Equipment Panelboards – industrial units http://conceptorg.com/techlibrary/PowerTechnology/AC_Load_Centers.pdf

LV Equipment Measuring Instruments Ammeter (I, A) Voltmeter (V, V) Frequency Meter (F, Hz) Power Factor Meter (pf) Power Meter (kW) Energy Meter (kW-hr) Current Transformers Universal Measuring Device No need to have voltage transformers because “LV Equipment”

LV Equipment Magnetic Contactors Switch controlled by electrical power Rating: Utilization Category AC1: general load p.f.>0.95 AC2: slip-ring motor (2.5 x In) AC3: squirrel cage motor (5 to 7 x In) disconnect at load AC4: squirrel cage motor (5 to 7 x In) and disconnect at the starting current

LV Equipment Magnetic Contactors - usage Commonly use in the motor starting circuit Direct-on-line Motor Starter (DOL) Start-Delta Motor Starter (Y) Auto Transformer Motor Starter Resistance Motor Starter

LV Equipment Switchboards Distribution panel that distribute the main power unit (e.g. out of transformer) to the branch circuit Standard: height around 2 to 2.2m Enclosure from steel sheet Protect against physical damage, thermal damage and erosion

LV Equipment Switchboards Busbar attached inside the enclosure Circuit Breaker: Main CB & Feeder CB Measuremnet Instrument Protection device (Ground Fault Protection, Lightning Arrestor) Follow standards (e.g. IEC60439)

LV Equipment Switchboards Rating: Rated Voltage, Rated Current, Rated Short-Circuit Current http://en.wikipedia.org/wiki/Electric_switchboard

LV Equipment Busways or Busduct Equipment that transmits power from one place to the other http://www.sengchai.com/busduct.html

LV Equipment Busway or Busduct Rating: Indoor or Outdoor usage, Voltage Drop, Rated Current, Short-Circuit Rating Busway can be reduced as long as the protection is still valid and the extension is no longer than 15.2m (50 ft)

Reference Electrical Systems Design: ประสิทธิ์ พิทยพัฒน์ Depend on the area, end-user can connect to the “meter” of the authority in three ways.