NWEMS Harris nstitute of echnical raining nstallation Planning (or what didn t learn at meter school) Presented by Brad Harris
nstallation #1 A three phase commercial customer has the following installation requirements for a new service and meter installation - Voltage 240 three phase, three wire DELA service otal connected load = 380 kw with an overall efficiency of 85% at unity power factor. How would you meter this customer and what are the metered values and metering components necessary to meter this load correctly? Please solve for the number of amps per phase that will be delivered to the customer s load at 380 kw (and 85% efficiency) amps nstalled meter information: Voltage Form Number Class
nstallation #1 Will current transformers be necessary to meter this load? Yes or No and WHY? f current transformers are necessary: What C ratio would be needed? : How many Cs will be needed? What minimum C rating factor would be necessary? f Cs are used, what would the secondary current from the Cs be when measured at the test switch at full load? amps What is the correct billing multiplier (billing K r ) for this meter installation? (meter K r = 1) Under what condition do we have to de-rate the rating factors of current transformers?
nstallation #2 You are to install a solid state meter with a pulse board that is programmed with a K e constant of.3 watt-hours per pulse. he installation has the following parameters: Meter Kh = 1.8 Current transformer ratio = 100:5 Voltage transformer = 60:1 Demand interval is 15 minutes Please solve for the following: Customer s kwhc = (3 wire pulse) Customer s kwc = (3 wire pulse) How many pulses will this meter send to the customer s receiving equipment per equivalent meter disk revolution? pulses
nstallation #3 A large single phase residential customer has the following installation requirements for a new service and primary metering installation - 4200 volt single phase primary service (phase to phase voltage from a phase to phase, single phase primary line) otal connected load = 120 kw with an overall efficiency of 80% at unity power factor How would you meter this customer and what are the metered values and metering components necessary to meter this load correctly? Please solve for the number of primary amps delivered to the customer s load at 120 kw (and 80% efficiency) amps nstalled meter information: Voltage Form Number Class
nstallation #3 Current transformer What C ratio would be needed? : What minimum C rating factor would be necessary? Voltage transformer What V ratio would be needed? : How many bushings will the V(s) have? 1 or 2 or will this matter? At full load what would the secondary current from the C be when measured at the test switch? amps What is the correct billing multiplier (billing K r ) for this meter installation? (meter K r = 1)
nstallation #4 What is the efficiency of a 120 volt, ¾ horsepower single phase pump which draws 12 amps from the 120 volt service to operate? % efficient (the motor runs at unity PF) nstallation #5 Please solve for the load factor for the following three phase commercial customer. he customer s demand and energy use for the previous month are: Peak demand read from the meter = 24 kw Energy use read from the meter = 5760 kwhs With the above meter reads what was this customer s load factor last month? (30 day month) %
nstallation #6 A single phase 240 volt, 40 kw electric motor pump load (100% efficient) is connected and running. his motor is running at a power factor of 75% (.7500) - What is the total kva of this motor load? kva What are the total amps being delivered to this motor load? amps How many kvar are flowing to this motor load? kvar With the information given and solved for, can this load be safely metered using a Class 200, Form 2S meter? Yes or No
nstallation #7 A customer is requesting 120/208 volt, three phase secondary power and related transformer bank connection. hey have a large amount of three phase load and a smaller amount of single phase load. Would this customer be connected to an Open or Closed primary bank connection? (Open/Closed) bank
nstallation #8 Given: A 125 horsepower, three-phase pump. What is the kw rating of this pump if it is 100% efficient, running at full load and 100% power factor? kw What would be the kva, kw and kvar magnitudes for this pump when operating at 80% (.8000) power factor? kva @ 80% = kw @ 80% = kvar @ 80% =
nstallation #9 New Customer Service Order Requested Secondary Voltage - 480 Single Phase Required Number of Secondary Wires - Connected Load in KW - 120 Amps Delivered to the Customer - New Meter nstall Record Meter Voltage - Meter Form Number - Meter Class - Current ransformer Ratio : 5 (if required) Number of Cs Required Minimum C Rating Factor Voltage ransformer Ratio : 1 (if required) NWEMS