What is Power Quality? - HyTEPS

wartrashyNetworking and Communications

Oct 26, 2013 (3 years and 9 months ago)

57 views

April
2013

Power Quality, Harmonics and Accuracy

Agenda


What is Power Quality


Improving Power Quality


Power Quality in SATEC products


Accuracy Standards

What is Power Quality?


Definitions of the quality of the supplied voltage (what about the current?)


Usually referred in negative contexts


power quality problems


Measurement


IEC
61000
-
4
-
7
Voltage Flicker


IEC
61000
-
4
-
15
Harmonic Measurement


IEC
61000
-
4
-
30
Measurement Accuracy (“Class A”, “Class S”)


IEC
62052
/
3
-
11
,
22
,
23
Energy Accuracy (“Class
0.2
S”, “Class
0.5
S”)


Power Quality


BS:EN
50160
:

In use worldwide, in favor of the utilities, voltage only,




statistical standard


IEEE
519
and IEEE
1159
: American standards, practical point of view


GOST
13019
:

Russian standard, very comprehensive


G
5
/
4
:


British standard for Harmonics (also current)


Customized:


Allows the user to select the best of all, including fault




recording, waveform capture and more


Frequency

Voltage Variations

Voltage Flicker

Voltage Dip

Power Quality Parameters

Interruptions

Temporary Overvoltage

Transients

Power Quality Parameters

Unbalance

Harmonics

Interharmonics

Power Quality Parameters

Harmonics

+

=

IEEE1159
-
EN50160 Levels

IEEE

1159

EN50160

No.

Categories

Typical Spectral
Content

Typical

Duration

Typical Voltage
Magnitude

Short Duration Variations

Instantaneous

7

Sag

0.5
-
30
Cycles

0.1
-
0.9
pu

<1 sec

8

Swell

0.5
-
30
Cycles

1.1
-
1.8
pu

No

Momentary

9

Interruption

0.5 Cycles
-
3s

<0.1
pu

<1 sec

10

Sag

30 Cycles
-
3s

0.1
-
0.9
pu

No

11

Swell

30 Cycles
-
3s

1.1
-
1.4
pu

No

Temporary

12

Interruption

3 s
-
1 min

<0.1
pu

No

13

Sag

3 s
-
1 min

0.1
-
0.9
pu

No

14

Swell

3 s
-
1 min

1.1
-
1.2
pu

No

Long

Duration

Variations

15

Interruption, Sustained

>1 min

0.0
pu

Yes

16

Undervoltages

>1 min

0.8
-
0.9
pu

Yes 10 min

17

Overvoltages

>1 min

1.1
-
1.2
pu

Yes 10 min

THD
-
Total Harmonic
Distortion

I
N
, V
N



Individual Harmonics of order N

(
I
)
TDD

-

ע םימרגנה םיקזנה תא ךירעהל תורשפא ןתונ
"
תוינומרה י

םימרזב
.

רשאכ
I max. demand

-

רוזחמב דדמנה םרז לש ילמיסקמ ךרע
לש ןמז
15

וא תוקד
30

הנש לש תללוכ הפוקתל תוקד
.

רטמרפ


THD I
%
םימרגנה םיקזנה תא ךירעהל תורשפא ןתונ אל
ע
"
רשאכו םיילנימונ םימרזל סחייתמ אל אוה יכ םימרזב תוינומרה י
הנוכנ אל הכרעה ןתונ אוה ךומנ תשרב םרזה
.

ןקתב וז הביסמ
IEEE

רטמרפ רדגומ םימרז רובע
TDD

.%

TDD
-

Total Demand Distortion

K
-
Factor

Agenda


What is Power Quality


Improving Power Quality


Power Quality in SATEC products


Accuracy Standards

Should we Care about Power Quality?

Comprehensive Research in Europe in
1400
sites at
8
countries reports that
20
% experience the following:


Computer lockouts (
20
%)


Light flickering (
22
%)


Electronic card failures (
18
%)


Power Factor correction system failures (
17
%)


Failures in high load switching (
16
%)


Neutral conductor overheating (
12
%)


Unexpected breaker operation (
11
%)


Power meters inaccurate readings (
6
%)


And of course excess losses and downtime






Causes and Solutions

PQ

Problem

Major Sources

Solutions

Frequency

The Utility

Voltage

variations

Load changing

Sync. loads,

Fast PF correction

Voltage flicker

Load changing, mainly
welding

Fast PF correction

Voltage dip

Motor and other load
startups

Motor starters, VFD,

Fast PF correction

Interruptions

The Utility

Overvoltage

Over PF compensation

Fast PF correction

Transients

Connections, Switching

Controlled switches

Unbalance

Unbalanced loads,
transformer

phase shift

Balance the loads

Harmonics

Non linear loads, resonance

Active/passive filtration,
detuned capacitors
,

Improved VFD operation

Agenda


What is Power Quality


Improving Power Quality


Power Quality in SATEC products


Accuracy Standards

RS
232
/
422
/
485
,
Profibus, TCP/IP
,
Dialup modem, GPRS,
RF, USB

Modbus RTU, ASCII, DNP
3.0
,
Modbus/TCP
,
DNP
3
/TCP
,
Profibus, IEC
61850
, IEC
60870

ETC
2002

COMMERCIAL & INDUSTRIAL

Multi
-
Tenant
Submetering

Power Measurement

Energy Efficiency & Cost Allocation

Energy Management & Billing

Asset Management

C
192
PF

BFM
136

PM
172


PM
174
/
5

EM
720

EM
920

ezPAC

PAS

PM
130
PLUS

LAN

ExpertPower


Server (Pro Edition)

The Full Range of Electricity Management Solutions for Every Application

EM
132
/
3

Substation

Automation

UTILITIES & RENEWABLE

ALL

Power Quality Analysis

Fault Recording

Revenue Metering

Smart Grid & Demand Response

PM
135

Internet

ExpertPower
™ Server
(Service Edition)

PM
180


Built in analysis to international power quality standards
such as EN
50160
, IEEE
1159
, G
5
/
4
and GOST



Automatic alerts for preventive maintenance



From simple compliance chart to sophisticated expert
analysis screens

EN
50160
Summary Report

List of Events

EN
50160
Compliance Trends

ITI
(
CBEMA
) Curve

Deep Analysis of a Dip

TDD at
22
kV

High Individual Harmonics

Agenda


What is Power Quality


Improving Power Quality


Power Quality in SATEC products


Accuracy Standards

Full
Scale (FS)
vs.
Reading


FS

=
Full
Scale, error in percents from the maximum
rating


Example:

Meter with
0.5
% FS accuracy connected to
1000
A
transformer, the error is
5
A. In
500
A load the accuracy
is
1
% (
5
/
500
)


Reading = Error from the measured value


In the above example, the
0.5
% error will be also in low
load, which means
2.5
A only

Accuracy vs. Standard


Various measurement conditions


Load


Harmonics


Power Factor


Frequency


and more…


Various ambient conditions


Temperature


EMC (the device and the accuracy)


Humidity


and more…


Tests by independent lab


Accuracy stability over time

(SATEC is approved for
8
years)


Power Factor and Cos



DPF = Displacement Power Factor (Cos φ)


TPF = True Power Factor (incl. harmonics)


Conclusion


practically there is no unity Power Factor.


Meter Class
0.5
Accuracy

IEC
62053
-
11

CT Class
0.5
Accuracy


IEC
60044
-
1

Power Factor

1.00

0.92

0.50

Error

of
45
minutes

0.015%

0.52%

1.14%

Power
Meter

0.8%

CT

0.75%

Phase

Shift

1.14%

System
Accuracy

1.58
%

System Accuracy

Meter Class
0.5
S Accuracy

IEC
62053
-
22

Power Factor

1.00

0.92

0.50

Error

of
30
minutes

0.004
%

0.34
%

0.76
%

CT Class
0.5
S Accuracy


IEC
60044
-
1

Power
Meter

0.6%

CT

0.5%

Phase
Shift

0.76%

System
Accuracy

1.
09
%

System Accuracy

HACS


High Accuracy Current Sensors


SATEC devices has
numerous amplitude and
phase calibration points

Power
Meter

0.6%

CT
-

Included

Phase
shift
-

Included

System
Accuracy
0.6
%

System Accuracy

Comparison

Class
0.5

Class 0.5S

Class 0.5S

with
HACSes

(or direct connection)

Power Meter Accuracy

0.8

0.6

0.6

CT Accuracy

0.75

0.5

Included

Phase Shift

1.14

0.76

Included

System Accuracy

1.58

1.09

0.6

Accuracy is for Engineers,

Money is for Decision Makers


1000
kVA

transformer


80
% load


0.90
Power Factor


0.15
US$/kWh


The difference between

0.6
% to
1.58
% equals to

US$
9
,
272
each year

Accuracy Standard Pyramid

Class A

Class S

Class
0.2
S

Class
0.5
S

Class 0.5

Class
1

Class
2

%Readings

%FS (Full Scale)

No stated

accuracy

61000
-
4
-
30

62053
-
22

IEC
62053
-
11

Min. Acceptable

Not included:

Class B


meaningless

Class
0.1
,
0.2


only for CTs

SATEC

Empowering the Smart Grid



www.satec
-
global.com