Firoz Abdullah

Electrical equipment – Power supplies 1 4 - Our power supplies  Grid network  Power plant  Transformers  Battery chargers  UPS  Emergency generators Electrical equipment: Power supplies Slide 2 1 4 - Grid network  Most of the time it is the normal way to feed our plants  Main data  Voltage: 15kV, 20kV, 25kV, 33kV, 63kV, 90kV, 110kV, 132kV, 150kV, 230kV with tolerance from ∓2,5% to ∓10%  The short circuit power (linked to the operation of the network)    Maximal value Minimal value We can have more or less than 2 values depending on the complexity of the grid (1 line, 2 lines, parallel,….. The short circuit impedance is Zsc = U²/Scc  The ratio R/X or the asymmetrical coefficient.  The response time of the protection installed by the supplier, the type of protection (simple current or “distance” and the settings, this, to ensure selectivity with the internal plant protections. Sometime it is possible to negotiate… Electrical equipment: Power supplies Slide 3 1 4 - Main grid supply Electrical equipment: Power supplies Slide 4 1 4 - Power plant  Can be Lafarge or somebody else property  Generally operation & maintenance subcontracted  Main data: Voltage: 6,6kV, 11kV, 15kV, tolerance can reach ∓15%  The kW (P) power and the kVA (S) power  The impedance of the generator(s) with the different configurations of operation     Sub-transient Transient Permanent  Minimal range of power  The response time and the type of the protection installed  The maximal impact load Electrical equipment: Power supplies Slide 5 1 4 - Power plant Electrical equipment: Power supplies Slide 6 1 4 - Transformer 1/2  Main data      Power in MVA, kVA, VA Primary voltage Secondary voltage Vector group Short circuit voltage in % of primary voltage Usc% :  This is the voltage required on primary side to obtain the rated current on secondary when this one is short circuited  Efficiency with 2 data: iron losses and winding losses  The possible setting(s) to obtain different secondary voltages with no load tap changer  The different voltage value obtained on secondary following position of the on load tap changer (main transformers)  The inrush current of a transformer when it is switched on is high (can reach 15 times the peak value of rated current  The short circuit impedance is : Zsc = U² x Usc% S x 100 Electrical equipment: Power supplies Slide 7 1 4 - Transformer 2/2 Main vector groups Used for MV/LV transformers (more in eastern countries) Often Dyn5 with neutral reachable Never use (primary = secondary) Network highly unbalanced Specific application Commonly used in our application for MV/LV transformers Often Dyn11 with neutral reachable Often used for HV/MV transformers Not common Electrical equipment: Power supplies Slide 8 1 4 - Battery charger  Here, we speak about rectifier + battery charger for batteries (sealed) capable to supply our control power supply during a period from 30 minutes to several hours      Depending on battery types, but they must be placed in ventilated rooms They are normally fed in 230 or 400Vac single phase The battery capacity is 25Ah ≤ C ≤ 60Ah During short circuit, can supply a current = 100 x rated current ➨ need attention to the breakers used for protection Must be equipped with failure information transmitted to control system    Main power available Battery failure Battery low voltage Electrical equipment: Power supplies Slide 9 1 4 - Electronic power supply  Here, we speak about power supply used for PLCs or DC control voltage for small actuators, sensors and I/Os  Main data        Are normally fed in 230Vac single phase and sometimes 3 phase 400Vac DC outlet voltage The rated current The rated power Efficiency Ripple voltage The short circuit current is ~ the rated current and sometimes becomes lower Electrical equipment: Power supplies Slide 10 1 4 - Uninterruptible power supply 1/3  There are 3 types: off line, in line and on line On line Off line  Often need inlet transformer to create neutral and…  Outlet transformer to create galvanic separation  Normally we use on-line Electrical equipment: Power supplies Slide 11 1 4 - Uninterruptible power supply 2/3  Used to supply 230Vac with accurate voltage and frequency required by our equipment which cannot support network disturbances related to drop of voltage, dips, or network interruption (PLCs, IT equipment…).  Includes electronic devices ➨ has a very low short circuit power (120% Ir during 1 or 2 seconds ➨ very limited distribution network ➨ one by workshop (modularity)  Main data        Rated power and possible overload (never use it) Input voltage (with internal or external insulation) The inlet frequency with acceptable range The battery voltage and its capacity in Direct Current The autonomy with rated power load The output voltage and frequency (with or without insulation) The data of the static bypass to move to second supply, the ability to operate with network additional supply Electrical equipment: Power supplies Slide 12 1 4 - Uninterruptible power supply 3/3  The off line type:  is more used for PC supply,  less used in industry,  is less expensive  In both case it is necessary to have isolators to allow maintenance operation without stoppage Electrical equipment: Power supplies Slide 13 1 4 - Emergency generator  Must be designed in accordance with the application  Main data         Voltage and frequency, Active power kW, Apparent power kVA, Type of cooling of the engine and of the generator Arrangement : on frame, in container, in shelter Autonomy in normal operation Mechanical protections Electrical data have to be known      Sub-transient impedance Transient impedance Permanent impedance Control and excitation modes Protections Electrical equipment: Power supplies Slide 14 1 4 - Thanks for your attention!!! Time for questions? Electrical equipment: Power supplies Slide 15