UPS SYSTEM TRAINING

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UPS SYSTEM TRAINING

• Design, Application, Testing and Maintenance
• Peter Ho, P.Eng.
• Schneider Electric

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Review Electrical Electronic Fundamentals

• Electrical (R, I, C)
• Resistance ( R )
• Definition The intensity of a constant electric
  current in a circuit is directly proportional to
  the electromotive force and inversely
  proportional to the resistance (George Simon Ohm)

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Review Electrical Electronic Fundamentals

• ReL/A eresistivity of the material
• No phase shift between V and I in a PURE
  resistance circuit (in phase)
• It is temperature dependant
• It consumes energy (unable to store energy)

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• Inductance ( L )
• It is a electro-magnetic device
• Definition A circuit has a inductance 1 henry
  when current change at 1A/sec then induces an EMF
  of 1 volt in that circuit (Joseph Henry)
• LV/di/dt VLdi/dt II/Lf Vdt
• V and I are not in phase ( 90 degree )
• Pure L can not consume energy only stores energy
• Pure L is not temperature dependant
• It is not possible to change the I through an L
  INSTANTLY
• XL 2 pri f L

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• Capacitance ( C )
• It is a electro-static device
• Definition A circuit has a capacitance of 1
  farad when a charge of 1 coulomb is required to
  raise the potential difference by 1 volt (Michael
  Faraday)
• I C dv/dt V 1/C f I dt
• Pure C can not consume energy but store energy
• C is not temperature dependant
• It is not possible to change the voltage across a
  C INSTANTLY
• Xc 2 pri f c
• The v and I are not in phase (90 degree )

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• QUESTIONS?

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• Understanding linear and non-linear
• Definition
• Linear Any electrical and electronic
  devices draw current in proportional to the
  voltage.
• Non-linear Any electrical and electronic
  devices draw current not in proportional to the
  voltage
• There are four types of load
• Linear Balanced and unbalanced
• Non-linear Balanced and non-balanced

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• Power Factor, Displacement PF, and K-rating
• The ratio between V and I
• The ratio between true power, reactive power
• Cosine of that angle is called power factor of
  that circuit.
• True power (Real power, active power W)

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Crest Factor

• Only for pure resistance
• Reactive power VAR is only for L and C
• Store energy in the first ¼ cycle and reflects
  back to the source on the second ¼ cycle
• Apparent power ( VA )
• It is a calculated value
• CF PEAK/RMS ratio that reflects
• the nature of the load

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• Displacement Power Factor
• It is because of non-linear load hence creating
  harmonic component
• Harmonic I can be shifted so that lagging behind
  the voltage (f)
• This will force the I (f) to shift along with the
  V (f)
• The total I2 I (f) 2 I (h) 2
• The shift of the I (f) wrt the V (f) is called
  displacement
• The cosine of that angle between I (f) and V (f)
  is called DPF

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Displacement Power Factor
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• Harmonics
• It is a by-product of any waveform that can be
  described in term of Fourier series
• F (t) A0 Sum An sin (nwt O)
• Ao DC component
• W 2 pri f
• 0 phase angle between V and I
• n integer
• A Magnitude of the n th harmonic
• Any electrical and electronic devices that
  operate in a saturation mode will produce
  harmonic (I)

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• K-Factor (Rating)
• It is defined as the non-linear load tolerance of
  a transformer or coil before it overheats
• K1 Purely linear
• K7 Less than 50 of 3 phase non-line
• K13 3 phase non linear load
• K20 Both single and 3 phase non-linear load
• K factor vs THD curve

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• Electrical Disturbances
• Control and uncontrolled
• Type of electrical disturbances
• Transients, impulses, oscillations, sags, swells,
  voltage deviations,
• Brownouts, power interruptions, v phase
  unbalance, frequency
• Deviation, electrical noise, EMI, etc and
  harmonic distortion

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Electrical Disturbances
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• Electrical Grounding
• Conservation of energy theory
• Grounding safety
• Grounding means connected to the Earth
• Earth Zero potential reference point
• System (I), equipment (no I), bonding (no I), N-G
  jumper (I)
• Only ONE N-G connection is allowed for each
  ISOLATED electrical system

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Electrical Grounding
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Electrical Bonding
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• Electronic - Diode, SCR, Bi-polar IGBT
• Type of solid
• Metal (carrier density 10 power 22)
• Semi-metal (cod 10 to the power 17-21)
• Semi-conductor (cod 10 to the power 17)
• Insulator (cod less than 1)

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Semi-conductors
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• Diode
• Two layers of semi-conductor (simple, building
  blocks)
• Richardsons Equation
• I A T2 e b/T
• I Emission current
• A Emission constant
• T Absolute temperature
• B work function, energy required by 1 electron
  to overcome the potential barrier (unit
  electronic volt)
• Way to force the e jump out the orbit becoming
  free
• Thermal, photo, secondary and cathode emission
• Turn on and turn off conditions

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Diodes
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• Bi-polar Transistor
• Three layers semi-conductors
• Current control device
• Icy B times I b
• It must be operated in the saturation mode

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• Silicon Controlled Rectifier (SCR)
• 4 layers semi-conductors (two transistors back to
  back)
• Current controlled device
• Turn on and turn off conditions
• Reverse recovery time and charge

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Silicon Controlled Rectifier (SCR)
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Insulated Gate Bi-polar Transistor IGBT

• Voltage controlled device
• Temperature dependant
• Fast switching with high power carrier
• Both bi-polar transistor and IGBT must be
  operated in a saturation
• Mode for any ups operation (creating harmonic)

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Insulated Gate Bi-polar Transistor IGBT
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UPS SYSTEM STUDY

• Why it is needed?
• Power quality issues (local and surrounding)
• Nature and non-nature (human)
• Equipment design limitation
• Protection of investment and life cycle
• Keep employment

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• Application of UPS
• Justification
• Any environment that needs 99.99 operational
  up-time
• Critical operations (life and )
• Insurance requirement

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• Types of UPS Systems
• On line and off line
• Static and rotary
• Battery and non-battery
• Double and delta conversion
• Flywheel technology
• Modern microprocessor control or traditional

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• UPS Configuration
• Single
• Parallel with or without system cabinet (for
  power or redundancy)
• Hot standby
• Two ups units with STS (dual application)
• Hot tie application
• Frequency convertor
• UPS conditioning without battery

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UPS Configuration
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UPS Configuration
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UPS BUILDING BLOCKS

• Most common UPS consists of the following
  building blocks
• Rectifier, charger, chopper, inverter, battery,
  bypass static switch
• Most common UPS consists of the following
  component
• Switch devices Diode, SCR, Transistor IGBT
• Disconnect devices Circuit breaker, disconnect
  switch, contactor, static switch
• Protection devices CB, fuse, fusible disconnect
  switch, air and liquid cooling system, earthquake
• Electrical system isolation device isolation
  transformer, M-G set
• Electrical component Resistor, inductor and
  capacitor
• Measurement parameters Voltage, current, rate of
  change of XXX, T, time Y-M-D
• Measurement devices PT, CT, Hall effect
  

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• RECTIFIER
• Rectifier and charger (different)
• Half and full wave
• Uncontrolled, half controlled and full
  controlled
• Unit-directional and bi-directional
• Main function Change AC into DC
• Major switching devices Diode, SCR, IGBT
• Input current harmonic order is N/-1 N of
  switching devices

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• CHOPPER
• It is a DC to DC converter
• Step up or step down
• Major components are Coil, diode, capacitor and
  high speed switching devices
• What is a DC (duty cycle)?
• Vout V in times DC
• Vout can not be more than 5 times the V in
• Reduce of battery in the system (only for lower
  KVA system)

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BREAK TIME
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• BATTERY
• It is a electro-chemistry device
• It can only store energy but can not create
  energy
• Fuel cell is the opposite of battery
• The battery voltage is determined by the ACTIVE
  material
• The battery capacity (A/H) is determined by the
  amount (weight) of the ACTIVE material
• For example The lead acid has 2.1V/cell 55
  AH/Kg
• The nickel cadmium has 1.35 V/cell
  165AH/Kg

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BATTERY TYPES
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• Factors Affecting Battery Performance
• , voltage, current, voltage regulation, nature
  of discharge, size, aging, environment condition
  (heat), AC ripple and more
• AS per Arrhenius Equation
• The worst factor that affects battery performance
  is temperature
• (Thermal runaway) - It is a non-reversible
• The internal battery Z decrease, the internal
  float current will be increased with the same
  voltage - the internal temperature will rise and
  may cause in accelerated dry out (melting the
  entire battery)
• As per Ohms Law
• For batteries are in series configuration the
  individual voltage across each battery SHOULD be
  the same
• The only item that affects the V is the internal
  individual Z
• That is the reason the battery Z tester is widely
  used
• However the result may not 100 reflect the
  condition of the battery

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• Since the battery is a perfect device to store
  electrical energy
• Safety is the most important matter
• For example, C/D seal battery UPS - 12- 475 FR
  has a 134AH_at_20 hours and 475W_at_15 minutes rating
• However the maximum discharge current is 800A and
  the short circuit current is 5000A
• Hence 12 V at 5000A 60,000 W (60KW) of power
  available at the battery fault location (terminal)

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• INVERTER
• Change DC to AC
• The switch devices can be transistor, SCR and
  IGBT
• Modulation can be AM, FM, PM (PM, PAM, PTM, PWM,
  PPM)
• PWM control the Vout without adding any power
  component
• Eliminate lower order harmonic. The high order
  harmonic can
• be easy filtered by smaller L/C network
• The inverter output frequency, amplitude, wave
  shape and phase shift are controlled by the
  switching device duty cycle

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• Internal Static Switch
• It is an essential part of UPS to remain no break
  transfer
• Also refer as internal automatic bypass switch
• It consists of 6 SCR (2 per phase)
• It is also bounded with SCR limitation and
  operation
• Using nature commuting to turn off SCR
• The worst case of the SS is un-controlled turn on
  with condition such as dv/dt (Ic C dv/dt)

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• UPS Specification
• Input section (voltage, current, frequency, slew
  rate, 3 wires or 4 wires plus G, delta or wyn
  source, isolated or non-isolated)
• Battery section (wet or seal) back up time,
  charging time requirement and monitoring system
• Single or parallel strings, of battery (DC bus
  voltage)
• Output section (Same as input with additional
  sync requirement)
• Forward and reverse transfer operation and
  limitation
• Bypass (internal and external) section

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• UPS System Testing Commissioning
• Factory testing (destruction)
• Site testing (non-destruction)
• Heat run with load bank (linear or non-linear)
  for X hours
• Harmonic (V I) measurement of input and output
• Step load requirement (0, 25, 50 75, 100
  125, 150 and 200)
• System overall n calculation (KW to KW)
• Battery discharging test as per sale order
• Battery recharging measurement and 2nd
  discharging test
• Noise and heat measurement
• Balanced and unbalanced output load testing
• Forward and reverse transfer operation waveform
  capture
• Maintenance bypass kirk key operation

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• Standby generator testing
• To observe UPS and generator interface operation
• Step load testing to ensure leading PF creating
  from the UPS
• To ensure there is no hunting
• Most important parameter is generator output
  frequency (amplitude and slew rate)
• UPS experience minimum or no alarm due to
  non-sync issue

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Generator

• Generator operation when UPS is on bypass (live
  load)
• In-rush current handing due to input transformers
  and/or inline inductors
• Generator sizing (1, 25, 50, 100 or higher)
• Generator feedback circuit

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• UPS System Maintenance
• Safety 1
• Trust no one but yourself
• Trust your calibrated testing equipment
• Wear your PPE
• Respect electricity
• Dont assume anything

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• Input section
• Measure V, I, F, PF, DPF, THD, KW, KVA
• Battery section
• Measure cell voltage, ripple AC V, I, individual
  cell internal Z and SG of wet cell
• Output section
• Measure V, I, F, PF, DPF, THD, KW, KVA and CF
• Voltage drop across any CB, contactor and SCR
  (very careful)
• 
  

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• Internal SS section
• Measure SCR leakage current when the system is on
  line
• Capacitors
• Measure input and output capacitor bank current
  and compare with each other
• Same for the DC capacitors
• Coil (choke)
• Measure the current of each branch

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• Visual inspection
• Transformers, coil discolor (sign of overheat)
• All AC and DC capacitors for unusual swelling
• Any cooling fans
• Any overheating cabling
• Dirty air filters
• Any contactor contact oxidation

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• Replacement component
• AC capacitors (filtering and timing type)
• AC (7-8 years) DC (5-6 years)
• Battery (4-5 years for seal and 15-18 years for
  wet cell)
• Cooling fans (5-6 years)

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External Interface

• Communication option (RS-232, 485, modbus, SNMP,
  dry relay
• Heating, smoking, fire, liquid, security, Co2,
  REPO (dedicated
• dry set of contact NO or NC)

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Case Studies

• SS failure due to thunderstorm and lightning
• Generators governor destroyed due to UPS on
  bypass mode (high CF)
• Non-TVSS UPS system installation as result, UPS
  input EMI filer damaged (Short circuit between
  phases)
• Missing N-G jumper creating UPS high output
  voltage

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• THANK YOU!