Transcript 5(A/D)

Group 8
Anthony McCorvey
Ronnie Lalchan
Chris Beck
George Thompson
Problem
 The power companies are
converting the old mechanical
meters to Smart meters.
 Wireless Communication
 Accurate Readings
 KWH every hour
 Power Factor
 Connect/Disconnect
 No jobs for meter readers
 Hiring untrained contractors
 Cheaper
 Looking for a cost efficient
method to train contractors
Goals
 To design a product that the power companies can use
for their renovations
 Cost efficient
 Safe
 User Friendly
 Test and Train
Design Requirements Hardware
 Meter Cans
 Potential Transformers
 Variable Transformer
 Toggle Switches/Relays
 Fuses
 Control Box
Thinking about the Design
 2 Phase Configurations
 Delta
 Wye
 Single Phase
Phase
Configuration
Phase to
Ground
Phase 1 to
Phase 2
Phase 2 to
Phase 3
and
Phase 3 to
Phase 1
Single Phase
Delta
120 Volts
240 Volts
240 Volts
Three Phase
Delta
120 Volts
240 Volts
240 Volts
Single Phase
Wye
120 Volts
208 Volts
Three Phase
Wye
120 Volts
208 Volts
 Three Phase
*Power
leg to
Ground
 How can we convert single phase to
three phase?
 Rotary motors etc
 Too expensive
 Defeats our goal
 “Trick the Voltage”
 That’s when Simulator was added to
the name
208 Volts
208
Volts
Meter Cans
 (2) Three Phase Meter Cans
 2 Wire Delta
 Junction Meter
 3 Wire Delta
 3 Wire Wye
 LED Lights

(3) Single Phase Meter Cans
 2 Wire Delta
 3 Wire Delta
 3Wire Wye
LED Lights (Safety Precautions)
Potential Transformers
 6 total potential transformers
 3 Step-down PT’s “Configuration”
 115:50 (Phase to Phase - Delta) and
(Phase to Ground – Delta and Wye)
 115:80 (Stinger leg Delta)
 115:42 (Phase to Phase – Wye)
3 Step-Up PT’s “Multiplier”
2.4:1
Step-Up PT Schematic
115
50
115
80
115
42
Secondary
Secondary
Secondary
Primary
Primary
Primary
S3
S3
Variable
Transformer
S3
Voltage Calculations
 Phase to Ground for Wye and Delta (115:50)
 50 x 2.4 = 120 Volts
 Power leg to Ground (Delta) (115:80)
 80 x 2.4 = 192 Volts
 Specific to needs
 Found a solution
 Phase to Phase for Wye to Delta
 Subtractive Polarity
 Delta



50 x 2.4 = 120 volts
Different terminals
120 <0 – 120 <180 = 240 Volts
 Wye (115:42)


42 x 2.4 = 100.8 Volts
100.8 <0 – 100.8 <180 = 201.6 Volts
Control Box
 Variable Transformer
 4 Fuses


(1) 5 Amps
(3) 2 Amps
 ON/OFF switch

Safety Precautions
 5 toggle switches for
selection of
configuration

3PDT
Delta Switching Sequence
Delta Single
Phase
Switch 1
Phase 1&2 to Up
Ground
Switch 2
Switch 3
Switch 4
Switch 5
Up
Up
Up
Down
Up
Up
Up
Up
Down
Phase 1&2 to Up
Ground
Up
Up
Up
Down
Power Leg to Up
Ground
Up
Up
Up
Up
Phase 1 to
Phase 2
Delta Three
Phase
Phase 1 to
Phase 2
Up
Up
Up
Up
Down
Phase 1 to
Power Leg
Up
Up
Up
Down
Down
Phase 2 to
Power Leg
Up
Up
Up
Down
Down
Wye Switching Sequence
Wye
Switch 1
Single Phase
Switch 2
Switch 3
Switch 4
Switch 5
Phase 1&2
to Ground
Up
Down
Up
Down
Down
Phase 1 to
Phase 2
Down
Down
Down
Up
Down
Up
Down
Up
Down
Down
Phase 1 to
Phase 2
Down
Down
Down
Up
Down
Phase 1 to
Phase 3
Down
Down
Down
Down
Down
Phase 2 to
Phase 3
Down
Down
Down
Down
Down
Wye Three
Phase
Phase 1,2,&3
to Ground
Phase Converter Simulator Hardware 1
Changing Switches to Relays
•
Mechanically changes configurations
• Allows microcontroller to control switching
• A lower voltage device can now control the
voltages of the meter cans
•
Eliminates need for the user to know list of
combinations
Relays
•
Type
Triple pole
double throw
(3PDT)
-
Impedance
Input voltage
Voltage
Required
to operate
Current
Required
120 Ω
6 – 240 VAC
8 - 14V
Min of .2 A
Schematic of Relay Connection
Testing
1. Tested relays by realizing the schematic
2. For the microcontroller, we applied a steady
voltage.
3. Connected to relays to microcontroller.
4. Replaced switched with relays.
Building
First attempt:
• Diode parallel with relay
• Purpose:
• Protect circuit from feedback current
when relay switched
• Diode shorted out the transistors
• Solution:
• Remove diode
Building
Second attempt:
• 1K resistor
• Limited current to microcontroller
• Too much impedance on breadboard
• Switch to 100 ohms
• Blew transistors 2n2222
• 2n2222 didn’t have a high enough rating
• Solution:
• Changed transistor to TIP120
Software Objective
 Create a Interface to compliment the Training
Simulation
 To allow the user to interact with the system.
 To give a visual reference to the user of his or her
actions
 Control Relays for Configuration Purposes
 Approve or Decline Users Certification
Software Components
 Microcontroller
 Voltmeter Circuit
 LCD Screen 2 line X 20 characters
LCD System Flow Chart
Push
Button
Voltmeter
Circuit
Switches to Switching Relays
 Microcontroller changes configurations
 Eliminates need for the user to know switch
combination
 Configurations can switch when required or prompted
automatically
LCD/system Code
Voltmeter Circuit(Feedback)
 Input Voltage (120-240)





|
Probes
|
Transformer
|
Full Wave Rectifier w/ Capacitor
|
Voltage Divider
|
A/D converter(microcontroller)
 Problems….
A/D Converter
-5(A/D)
Voltage
+5(A/D)
115V-.284V(53)
120V
125V-.385V(77)
203V-1.85V(379)
208V
213V-1.87V(385)
235V-1.88V(388)
240V
245V-1.91V(397)
PCB
 2 Layer PCB
 .10” Traces
 Ground Plane
 Using PCB Express
 Schematic
 PCB Board
Schematic
PCB Board
Microcontroller Vs. FPGA
PIC16F876A
ATmega168
FPGA Basys
ATmega168
Features
I/0 Pins
Memory Type
Program Memory (KB)
EEPROM (Bytes)
SRAM (KB)
Operating Voltage
ATmega168
23
FLASH
16
512
1
5.5 Volts
PIC16F876A
Features
I/0 Pins
Memory Type
Program Memory (KB)
EEPROM (Bytes)
SRAM (KB)
Operating Voltage
PIC16F876A
22
FLASH
14
256
0.359
5.5 Volts
FPGA Basys
Features
I/0 Pins
Memory Type
Program Memory (KB)
EEPROM (Bytes)
SRAM (KB)
Operating Voltage
FPGA Basys
24
FLASH
72
72
3.3 Volts
Microcontroller Vs. FPGA
Features
ATmega168
I/0 Pins
PIC16F876A
FPGA Basys
23
22
24
FLASH
FLASH
FLASH
Program Memory (KB)
16
14
72
EEPROM (Bytes)
512
256
-
1
0.359
72
5.5 Volts
5.5 Volts
3.3 Volts
Memory Type
SRAM (KB)
Operating Voltage
•ATmega168
Budget
Part
Switches
Fuses
Enclosure
Three Phase Meter Box
Single Phase Meter Box
Potential Transformer
Wiring
Microcontroller
Interface
Volt Meter
A/D converter
Variable Transformer
User Interface
Keyboard
Total:
Development Immediate Cost Prototype
$10
$10
$30
$140
$75
$60
$0
$60
$60
$30
$40
$0
$50
$0
$10
$10
$30
$140
$75
$60
$30
$60
$60
$30
$40
$100
$50
$30
$10
$10
$30
$140
$75
$60
$30
$60
$60
$30
$40
$100
$50
$30
$565.00
$725.00
$725.00
Budget Analysis
Immediate Cost
Keyboard
4%
Switches
2% Fuses Enclosure
2%
User Interface
4%
7%
Switches
Fuses
Enclosure
Three Phase Meter Box
Three Phase
Meter Box
19%
Variable
Transformer
14%
Single Phase Meter Box
Potential Transformer
Wiring
Microcontroller
A/D converter
6%
Volt Meter
4%
Single Phase
Meter Box
10%
Interface
8%
Microcontroller Wiring
8%
4%
Interface
Volt Meter
A/D converter
Variable Transformer
User Interface
Potential Transformer
8%
Keyboard
Budget
 Current Cost $550
 Development Budget $565
 Prototype Budget $725
Thanks
 Family
 Faculty
 Friends