A |
component availability (Chapter 11) |
A |
levelized annual cost, $ (Chapter 7) |
A |
weighted average Btu/kWh net generation (Chapter 2) |
A, B, C |
phase designation |
A, B, C, D |
general line (circuit) constants (Chapter 5) |
AFDR |
feeder availability (Chapter 11) |
Ai |
availability of component i (Chapter 11) |
An |
area served by one of n substation feeders, mi2 |
ASD |
service-drop conductor size, cmil (Chapter 6) |
ASL |
secondary-line conductor size, cmil (Chapter 6) |
Asys |
system availability (Chapter 11) |
AEC |
annual equivalent of energy cost, $ |
AEICc |
annual equivalent of total installed capacitor bank cost, $ (Chapter 8) |
AIC |
annual equivalent of feeder investment cost, $ |
B |
average fuel cost, $/MBtu (Chapter 2) |
BEC |
original (base) annual kWh energy consumption |
BVR |
bus voltage regulator |
BW |
bandwidth of voltage-regulating relay |
C |
capacitance, F |
C |
common winding (Chapter 3) |
CF |
installed feeder cost, $/kVA (Chapter 8) |
CG |
generation system cost, $/kVA |
CS |
distribution substation cost, $/kVA |
CT |
transmission system cost, $/kVA |
CT |
transmission cost, $/kVA (Equation 8.26) |
CT |
total reactive compensation (= cn) (Equation 8.85) |
CR |
corrective ratio (Chapter 9) |
CTP |
primary-side rating of current transformer (Chapter 9) |
CTR |
current transformer ratio |
D |
distance or separation, ft |
D |
load density, kVA/mi2 |
D |
ratio of kWh losses to net system input (Chapter 2) |
Dg |
coincident maximum group demand, W |
Di |
demand of load i, W |
DFi |
demand factor of load group i |
DTA(ij, k) |
downtime array coefficients (Chapter 11) |
E |
source emf; voltage |
Ei |
event that component i operates successfully (Chapter 11) |
EC |
energy cost, $/kWh |
ECoff |
incremental cost of off-peak electric energy, $/kWh |
ECon |
incremental cost of on-peak electric energy, $/kWh (Chapter 6) |
ECL1 |
eddy-current loss at rated fundamental current |
E(T) |
expected time during which a component will survive |
F |
fault point |
F’LD |
reactive load factor (= Q/S) |
Fc |
coincident factor |
FD |
diversity factor |
FLD |
load factor |
FLL |
load-location factor (Chapter 7) |
FLS |
loss factor |
FLSA |
loss-allowance factor (Chapter 7) |
FPR |
peak-responsibility factor |
FR |
reserve factor |
Fu |
utilization factor |
FCAF |
fuel cost adjustment factor, $/kWh |
FDR |
feeder (Chapter 11) |
F(t) |
unreliability function (Chapter 11) |
H |
transformer higher-voltage-side winding |
HFI |
current harmonic factor |
HFV |
voltage harmonic factor |
I |
failed zone-branch array coefficient (Chapter 11) |
I |
rms phasor current, A |
I |
current matrix |
IAB |
current in higher-voltage-side winding between phases A and B, A |
Iab |
current in lower-voltage-side winding between phases a and b, A |
Ia,3ϕ |
current in phase a due to single-phase load, A |
IB |
base current, A |
IC |
current in common winding (Chapter 3) |
Ic |
core-loss component of excitation current (Chapter 3) |
Ie |
excitation current (Chapter 3) |
Iexc |
per unit excitation current (Chapter 6) |
If,a, If,b If,c |
fault currents in phases a, b, and c |
If,3ϕ |
three-phase fault current, A |
If,3ϕ |
three-phase fault current referred to subtransmission voltage, A (Chapter 10) |
(IF,3ϕ)max |
maximum three-phase fault current, A (Chapter 10) |
IF, HV |
fault current in transformer high-voltage side, A |
If,L–G |
line-to-ground fault current, A |
If, LV |
fault current in transformer low-voltage side, A |
If,L–L |
line-to-line fault current, A |
Iϕ1 |
current due to single-phase load, A |
Ih |
harmonic current |
IL |
line current; load current, A |
Im |
magnetizing current component of excitation current (Chapter 3) |
Im |
current in feeder main at substation, A |
IN |
current in primary neutral, A |
In |
current in secondary neutral, A |
Iop |
operating current, A |
IP, pu |
no-load primary current at substation transformer, pu |
Ira |
rated current, A |
IS |
current in series winding (Chapter 3) |
ICc |
installed cost of capacitor bank, $/kvar (Chapter 8) |
ICcap |
total installed cost of shunt capacitors, $ |
ICF |
installed feeder cost, $ (Chapter 7) |
ICPH |
annual installed cost of pole and its hardware, $ (Chapter 6) |
ICSD |
annual installed cost of service drop, $ (Chapter 6) |
ICSL |
annual installed cost of secondary line, $ (Chapter 6) |
ICsys |
average investment cost of power system upstream, $/kVA |
ICT |
annual installed cost of distribution transformer, $ |
K |
percent voltage drop per kilovolt-ampere-mile |
per unit voltage drop per 10,000 A · ft |
|
constant (Equation 5.63) |
|
Kh |
watt-hour meter constant (Chapter 2) |
KR |
conversion factor for resistance (Chapter 7) |
Kr |
number of watt-hour meter disk revolutions (Chapter 2) |
KX |
conversion factor for reactance (Chapter 7) |
K1 |
a constant to convert energy-loss savings to dollars, $/kWh (Equation 8.87) |
K2 |
a constant to convert power-loss savings to dollars, $/kWh (Equation 8.87) |
K3 |
a constant to convert total fixed capacitor size to dollars, $/kWh (Equation 8.95) |
Lsc |
system inductance, H (Equation 8.108) |
LCDH |
losses in capacitors due to harmonics |
LD |
load diversity, W |
LD |
load (Chapters 2 and 5) |
LDC |
line-drop compensator |
LS |
loss |
LTC |
load tap changer |
LV |
low voltage |
MTTR |
mean time to repair () (Chapter 11) |
MTBF |
mean time between failures () (Chapter 11) |
MTTF |
mean time to failure () (Chapter 11) |
N |
expected duration of normal weather (Chapter 11) |
N |
neutral primary terminal |
0 |
row vector of zeros (Chapter 11) |
OCexc |
annual operating cost of transformer excitation current, $ (Chapter 6) |
OCSD, Cu |
annual operating cost of service-drop cable due to copper losses, $ (Chapter 6) |
OCSL, Cu |
annual operating cost of secondary line due to copper losses, $ (Chapter 6) |
OCT, Cu |
annual operating cost of transformer due to copper losses, $ (Chapter 6) |
OCT, Fe |
annual operating cost of transformer due to core losses, $ |
P |
average power, W |
P |
transition (or stochastic) matrix (Chapter 11) |
P’LS |
power loss after capacitor bank addition, W (Equation 8.46) |
Pav |
average power, W |
PLS, av |
average power loss, W |
Pi |
peak load i, W |
PLD |
average power of load, W |
PLS |
average power loss, W |
PLS, i |
peak loss at peak load i, W |
PLS, max |
maximum power loss, W |
PLS,1ϕ |
single-phase power loss, W (Chapter 7) |
PLS,3ϕ |
three-phase power loss, W (Chapter 7) |
Pn |
load at year n, W (Chapter 2) |
P0 |
initial load, W |
Pr |
receiving-end average power, VA |
PT, Cu |
transformer copper loss, W (Chapter 6) |
PT, Fe |
transformer core loss, W (Chapter 6) |
PSL, Cu |
power loss of secondary line due to copper losses, W |
PF |
power factor |
PTR |
potential transformer ratio |
PTN |
turns ratio of potential transformer (Chapter 9) |
Q |
average reactive power, var |
Qc |
reactive power due to corrective capacitors, var (Chapter 8) |
Qc,3ϕ |
three-phase reactive power due to corrective capacitors, var (Equation 8.30) |
Qi |
unreliability of component i (Chapter 11) |
Qr |
receiving-end average reactive power, VA |
Qsys |
system unreliability (Chapter 11) |
R |
resistance, Ω |
Reff |
effective resistance, Ω (Chapter 9) |
RL |
resistance of load impedance, Ω |
Rset |
R dial setting of line-drop compensator (Chapter 9) |
Rsys |
system reliability (Chapter 11) |
RIA(ij, k) |
recognition and isolation array coefficients (Chapter 11) |
RP |
regulating point |
S |
apparent power, VA |
|
= P + jQ, complex apparent power, VA |
S |
expected duration of adverse weather (Chapter 11) |
S |
series winding (Chapter 3) |
SB |
base apparent power, VA |
Ssc |
short-circuit apparent power, VA |
Sckt |
circuit capacity, VA (Chapter 9) |
SG |
generation capacity, VA (Chapter 8) |
SL |
load apparent power, VA |
SLi |
apparent power of load i, VA |
apparent power rating of an open-delta bank |
|
Slump |
apparent power of lumped load, VA |
SL,3ϕ |
three-phase apparent power of load, VA (Chapter 8) |
Sm |
total kVA load served by one feeder main |
Sn |
kVA load served by one of n substation feeders |
SPK |
feeder apparent power at peak load, VA |
Sreg |
regulator capacity, VA (Chapter 9) |
SS |
substation capacity, VA (Equation 8.27) |
ST |
transformer apparent power, VA |
ST |
transmission capacity, VA (Equation 8.24) |
ST, ab |
apparent power rating of single-phase transformer connected between phases a and b, VA |
STi |
apparent power rating of transformer i, VA |
ST,3ϕ |
three-phase transformer apparent power, VA |
S1ϕ |
single-phase VA rating |
S3ϕ |
three-phase VA rating |
SΔ–Δ |
apparent power rating of a delta-delta bank |
SD |
service drop (Chapter 6) |
SW |
switchable capacitors (Chapter 8) |
T |
a random variable representing failure time (Chapter 11) |
T |
time |
T |
transformer |
TAn |
total area served by all n feeders, mi2 |
TAC |
total annual cost, $ |
TAELcu |
total annual energy loss due to copper losses, W |
TCDi |
total connected group demand i, W |
TD |
time delay |
TECL |
total eddy-current loss (Chapter 8) |
TSn |
total kVA load served by a substation with n feeders |
U |
component unavailability (Chapter 11) |
UFDR |
feeder unavailability (Chapter 11) |
UG |
underground |
URD |
underground residential distribution |
V |
volt, unit symbol abbreviation for voltage |
V |
voltage matrix |
Vab, pu |
voltage between phases a and b, pu |
VB,ϕ |
single-phase base voltage, V |
VB,3ϕ |
three-phase base voltage, V |
VC |
voltage across common winding (Chapter 3) |
VH |
higher-voltage-side voltage, V (Chapter 3) |
Vh |
rms voltage of hth harmonic |
VL-L |
line-to-line distribution voltage, V (Chapter 10) |
VL-L |
line-to-line voltage, V |
VL-N |
line-to-neutral voltage, V |
Yl, pu |
per unit voltage at feeder end (Chapter 9) |
VP |
primary distribution voltage, V (Chapter 9) |
VP, max |
maximum primary distribution voltage, V |
Vr |
receiving-end voltage |
Vreg |
output voltage of regulator, V |
VRP |
voltage at regulating point, V |
VS |
voltage across series winding (Chapter 3) |
VS |
sending-end voltage |
VST |
subtransmission voltage, V (Chapter 9) |
VST, L–L |
line-to-line subtransmission voltage, V (Chapter 10) |
VX |
lower-voltage-side voltage, V (Chapter 3) |
VD |
voltage drop, V |
VDpu |
per unit voltage drop |
VDpu,1ϕ |
single-phase voltage drop, pu |
VDpu,3ϕ |
three-phase voltage drop, pu |
VDSD |
voltage drop in service-drop cable, V |
VDSL |
voltage drop in secondary line, V |
VDT |
voltage drop in transformer, V |
% VDab |
percent voltage drop between a and b |
% VDm |
percent voltage drop in feeder main |
VDIP |
voltage dip, V |
VDIPSD |
voltage dip in service-drop cable, V |
VDIPSL |
voltage dip in secondary line, V |
VDIPT |
voltage dip in transformer, V |
VRl, pu |
per unit voltage rise at distance 1 (Chapter 9) |
VRpu |
per unit voltage regulation |
% VR |
percent voltage regulation |
% VR |
percent voltage rise (Chapter 8) |
% VRNSW |
percent voltage rise due to nonswitchable capacitors (Chapter 8) |
% VRSW |
percent voltage rise due to switchable capacitors (Chapter 8) |
VRR |
voltage-regulating relay |
VRRpu |
per unit setting of voltage-regulating relay |
W |
wire (in transformer connections) (Chapter 3) |
X |
reactance, Ω; transformer lower-voltage-side winding |
Xc |
capacitive reactance |
XL |
reactance of load impedance, Ω |
Xsc |
system reactance, Ω (Equation 8.107) |
Xset |
X dial setting of line-drop compensator (Chapter 9) |
X(tn) |
sequence of discrete-valued random variables (Chapter 11) |
Y |
admittance, Ω; wye connection |
Y |
admittance matrix |
Z |
impedance, Ω |
Z |
secondary-winding impedance, Ω (Equation 10.71) |
Z |
impedance matrix |
Zeq |
equivalent (total) impedance to fault, Ω (Chapter 10) |
Zf |
fault impedance, Ω |
ZG |
impedance to ground, Ω |
ZG, ckt |
impedance to ground of circuit, Ω |
ZLD |
load impedance, Ω |
ZM |
impedance of secondary main, Ω |
ZT |
transformer impedance, Ω |
ZT |
equivalent impedance of distribution transformer, Ω |
ZT, pu |
per unit transformer impedance |
ZΔ |
equivalent delta impedance, Ω (Equation 10.54) |
Z0 |
zero-sequence impedance, Ω |
Z0, ckt |
zero-sequence impedance of circuit, Ω |
Z1 |
positive-sequence impedance, Ω |
Z1, ckt |
positive-sequence impedance of circuit, Ω |
Z1, SL |
positive-sequence impedance of secondary line, Ω (Chapter 10) |
Z1, ST |
positive-sequence impedance of subtransmission line, Ω |
Z1, sys |
positive-sequence impedance of system, Ω |
Z1, T |
positive-sequence impedance of transformer, Ω |
Z2 |
negative-sequence impedance, Ω |
a, b, c |
phase designation |
c |
capacitor compensation ratio (Chapter 8) |
ci |
contribution factor of load i |
dn |
mutual geometric mean distance of phase and neutral wires, ft |
dp |
mutual geometric mean distance between phase wires, ft |
mean failure frequency (Chapter 11) |
|
fP |
parallel resonant frequency, Hz |
f1 |
fundamental frequency, Hz |
fsys |
average failure frequency of a system (Chapter 11) |
f(t) |
probability density function |
h |
harmonic order |
h(t) |
hazard rate (Chapter 11) |
i |
investment fixed charge rate (Chapter 6) |
ic |
annual fixed charge rate for capacitors |
iF |
annual fixed rate for feeder |
iG |
annual fixed charge rate for generation system |
is |
annual fixed charge rate for distribution substation |
iT |
annual fixed charge rate for transmission system |
k |
constant used in computing loss factor (Chapter 2) |
l |
inductance per unit length; leakage inductance |
l |
feeder length, mi |
ln |
linear dimension of primary-feeder service area, mi |
mi |
observed time to failure for cycle i (Chapter 11) |
mean time to failure of series system (Chapter 11) |
|
n |
total number of cycles (Chapter 11) |
n |
transfer ratio (inverse of turns ratio) (Chapter 10) |
n |
= n1/n2, turns ratio; neutral secondary terminal; number of feeders emanating from a substation |
n1 |
number of turns in primary winding |
n2 |
number of turns in secondary winding |
P(n) |
vector of state probabilities at time tn (Chapter 11) |
pij |
transition probabilities (Chapter 11) |
pij |
probability of proper operation of isolating equipment in zone branch ij (Chapter 11) |
q |
probability of component failure (Chapter 11) |
qij |
probability of failure of isolating equipment in zone branch ij (Chapter 11) receiving end |
r |
radius; internal (source) resistance; resistance per unit length |
ra |
resistance of phase wires, Ω/ 1000 ft |
re |
earth resistance, Ω/ 1000 ft |
req |
transformer equivalent resistance, Ω |
ri |
observed time to repair for cycle i (Chapter 11) |
rl |
lateral resistance per unit length |
rm |
resistance of feeder main, Ω/ mi |
mean time to repair of series system (Chapter 11) |
|
s |
sending end; effective feeder (main) length, mi (Chapter 4) |
s |
series system (Chapter 11) |
t |
time |
x |
line reactance per unit length; internal (source) reactance |
xa |
self-inductive reactance of a phase conductor, Ω/ mi |
xap |
reactance of phase wire with 1 ft spacing, Ω/ 1000 ft |
xan |
reactance of neutral wire with 1 ft spacing, Ω/ 1000 ft |
xd |
inductive reactance spacing factor, Ω /mi |
xdn |
mutual reactance between phase and neutral wires, Ω/ 1000 ft |
xdp |
mutual reactance of phase wires, Ω/ 1000 ft |
xe |
earth reactance, Ω/ 1000 ft |
xeq |
transformer equivalent reactance, Ω |
xi, opt |
optimum location of capacitor bank i in per unit length |
xL |
inductive line reactance (Chapters 5 and 8) |
x1 |
lateral reactance per unit length |
xm |
reactance of feeder main, Ω/ mi |
xRP |
regulating point distance from substation, mi (Chapter 9) |
xT |
transformer reactance, % Ω (Chapter 8) |
Z |
impedance per unit length |
Zl |
lateral impedance per unit length |
zm |
impedance of feeder main, Ω/ mi |
Z0, a |
zero-sequence self-impedance of phase circuit, Ω/ 1000 ft |
Z0, ag |
zero-sequence mutual impedance between phase and ground wires, Ω/ 1000 ft |
Z0, g |
zero-sequence self-impedance of ground wire, Ω/ 1000 ft |
Δ |
delta connection; determinant |
Δ |
difference; increment; savings; benefits |
ΔACE |
annual conserved energy, Wh (Chapter 8) |
ΔBEC |
additional energy consumption increase |
ΔEL |
energy-loss reduction |
ΔPLS |
additional decrease in power loss, W (Chapter 8) |
ΔPLS, opt |
optimum loss reduction, W (Chapter 8) |
ΔQc |
required additional capacitor size, var (Chapter 8) |
ΔSF |
released feeder capacity, VA (Chapter 8) |
ΔSG |
released generation capacity, VA (Chapter 8) |
ΔSS |
released substation capacity, VA (Equation 8.29) |
ΔST |
released transmission capacity, VA (Equation 8.24) |
ΔSsys |
released system capacity, W (Chapter 8) |
Δ$ACE |
annual benefits due to conserved energy, $ (Chapter 8) |
Δ$F |
annual benefits due to released feeder capacity, $ (Equation 8.36) |
Δ$G |
annual benefits due to released generation capacity, $ (Chapter 8) |
Δ$S |
annual benefits due to released substation capacity, $ (Equation 8.29) |
Δ$T |
annual benefits due to released transmission capacity, $ (Equation 8.26) |
Δ |
transition rate matrix (Chapter 11) |
Π |
unconditional steady-state probability matrix (Chapter 11) |
Σ |
total savings due to capacitor installation, $ (Equation 8.86) |
α |
a constant [=(1 + λ + λ2)]−1 (Chapter 11) 6 |
δ |
power angle |
θ |
power-factor angle |
θmax |
power-factor angle at maximum voltage drop |
λ |
ratio of reactive current at line end to reactive current at line beginning |
λ |
failure rate (Chapter 11) |
complex flux linkages, (Wb · T)/m |
|
λCT |
annual fault rate of cable terminations (Chapter 11) |
λFDR |
annual feeder fault rate (Chapter 11) |
λij |
total failure rate of zone branch ij (Chapter 11) |
λijB |
breaker failure rate in zone i branch j (Chapter 11) |
λijM |
zone branch ij failure rate due to preventive maintenance (Chapter 11) |
λijW |
zone branch ij failure rate due to adverse weather (Chapter 11) |
λOH |
annual fault rate of overhead feeder section (Chapter 11) |
λs |
failure rate of supply (substation) (Chapter 11) |
λUG |
annual fault rate of underground feeder section (Chapter 11) |
μ |
mean repair rate (Chapter 11) |
μij |
zone branch ij repair rate (Chapter 11) |
μsijc |
reclosing rate of reclosing equipment in zone branch ij (Chapter 11) |
μsijo |
isolation rate of isolating equipment in zone branch ij (Chapter 11) |
ϕ |
= tan−1(X/R), impedance angle |
ϕ |
magnetic flux; phase angle |
ω |
radian frequency |
A |
phase a |
a |
phase a |
B |
phase b |
b |
phase b |
B |
base quantity |
C |
phase C; common winding (Chapter 3) |
c |
phase c |
c |
capacity; capacitive; coincident (Chapter 3) |
cap |
shunt capacitor |
ckt |
circuit |
CT |
cable termination (Chapter 11) |
Cu |
copper |
eff |
effective |
eq |
equivalent circuit quantity |
exc |
excitation |
D |
diversity |
F |
feeder; fault point; referring to fault |
f |
referring to fault |
FDR |
feeder |
Fe |
iron |
H |
high-voltage side (HV) |
L |
inductive (reactance); load (Chapter 3) |
L |
line; load |
l |
lateral; inductive (reactance); length |
LD |
load |
L-G |
line-to-ground |
L-L |
line-to-line |
LL |
load location (Chapter 7) |
L-N |
line-to-neutral |
LS |
loss (Chapters 2 and 5) |
LSA |
loss allowance |
M |
secondary main |
m |
feeder main |
max |
maximum |
min |
minimum |
N |
turns ratio |
N |
primary neutral |
n |
number of feeders emanating from a substation |
n |
neutral |
NSW |
nonswitchable (fixed) capacitors (Chapter 9) |
off |
off-peak |
OH |
overhead (Chapter 11) |
op |
operating |
opt |
optimum |
on |
on-peak |
• |
primary |
PK |
peak |
PR |
peak responsibility (Chapter 7) |
pu |
per unit |
r |
receiving end |
ra |
rated |
reg |
regulator |
S |
substation; series winding (Chapter 3) |
s |
sending end |
sc |
short circuit |
SD |
service drop |
set |
dial setting (line-drop compensator) |
SL |
secondary line (Chapter 6) |
ST |
subtransmission |
SW |
switchable (capacitors) |
sys |
power system |
T |
transformer |
Ti |
transformer i |
X |
low-voltage side (LV) |
Y |
wye connection |
1ϕ, 3ϕ |
single-phase, three-phase |
0, 1, 2 |
zero-, positive-, negative-sequence quantity |
Δ |
delta connection |
∠ |
open-delta connection |
3.133.157.12