EE544 Distribution 1

1
EE544 Distribution 1

• Distribution Feeder Analysis
• Regulation of Voltages

2
Feeder Analysis

• Feeder Analysis
• Voltage Regulation

3
Feeder Analysis

• Examples will use following Data

4
Feeder Analysis

• Examples will use following Data

5
Feeder Analysis
287 KVA 0.0.87 pf lag
5
C3 b
Sub
C1 5000 C1 5000
2
3
1
C3 a
618 KVA 0.874 pf lag
13800 kV
732 KVA 0.82 pf lag
Source impedance j0.005 pu
4
221 KVA 0.9 pf lag
6
Feeder Analysis
YOH12 YS
-YOH12
YOH12 YOH23 Yuga25 Yuga24
-YOH12
-Yuga24
-YOH12
-Yugb25
YOH23
-YOH12
Yuga24
-Yuga24
Yugb25
-Yugb25
7
Feeder Analysis
VSa/Zs VSb/Zs VSc/Zs -(S2a/V2a).
-(S2a/V2a) I -(S2a/V2a) . .
.
8
Feeder Analysis
VSa/Zs VSb/Zs VSc/Zs -(S2a/V2a).
-(S2a/V2a) I -(S2a/V2a) . .
.
V Z I
9
Feeder Analysis
VSa/Zs VSb/Zs VSc/Zs -(S2a/V2a).
-(S2b/V2b) I -(S2c/V2c) . .
.
V Z I
deg
V
10
Feeder Analysis
Current and power in branch 2-3
11
Feeder Analysis
At source
12
Voltage Control and Regulation
Capacitor banks Relatively Inexpensive -
Provide voltage rise - Reduce current when
properly located - Release capacity - Provide
Transmission Support The capacitor application
problem - Location - Size Minimize A1
Capital cost A2 PW of Loss - A3
Released Capacity Credit
13
Voltage Control and Regulation
Capacitor banks (Shorts Handbook)
14
Voltage Control and Regulation
Capacitor banks Ideally correct at source of
problem, i.e., Load - too many banks
expensive Typically locate 3-phase banks along
primary and 3 phase laterals - Uniform Primary
ROT 2/3 VARS 2/3 down from sub - Fixed Banks -
Switch banks typically oil or vacuum switch
OH or padmount - Radio controlled from
Distribution Control System - Time
controlled - Voltage Switched Requires PT -
Current Switched Requires CT - Reactive
Current Switched - Watch CT location -
Coordination
15
Voltage Control and Regulation- Capacitors
Capacitor banks Ideally correct at source of
problem, i.e., Load - too many banks
expensive Typically locate 3-phase banks along
primary and 3 phase laterals - Uniform Primary
ROT 2/3 VARS 2/3 down from sub - Fixed Banks -
Switch banks typically oil switch OH or
padmount - Radio controlled from Distribution
Control System - Time controlled - Voltage
Switched Requires PT - Current Switched
Requires CT - Reactive Current Switched -
Watch CT location - Coordination
16
Voltage Control and Regulation- Capacitors
287 KVA 0.0.87 pf lag
5
618 KVA 0.874 pf lag
C3 b
Sub
C1 5000 C1 5000
2
3
1

• 600 KVAR bank here
• Good voltage rise
• Overcompensates
• May even increase loss

C3 a
13800 kV

• 600 KVAR bank here
• Moderate voltage rise
• Less Overcompensates
• Does not decrease loss
• here

732 KVA 0.82 pf lag
Source impedance j0.005 pu
4
221 KVA 0.9 pf lag
17
Voltage Control and Regulation- Capacitors
18
Voltage Control and Regulation- Capacitors
19
Voltage Control and Regulation- Capacitors
Note improved voltage profile Capacitor at bus 2
or 3 has same effect on Bus 2 Capacitor at 3
gives additional rise at bus 3 Losses stay the
same Bus 3 is the better loacation
Phase a voltage magnitudes At nodes 1 2 and
3 Without cap VAold Cap. At bus 2
Vcap_at2 Cap At bus 3 -- VA