Digital Mimic · ALPS is a multi-function digital protective relay system intended to provide distance protection for HV or EHV transmission lines. ALPS Advanced Line Protection System

ALPS™ALPS™Advanced Line Protection SystemAdvanced Line Protection System

2

Modified Fourier Calculation

ALPS Advanced Line Protection System

• High Speed Sampling

• Phaselet Calculation

• Variable Window

• Digital Mimic

High Speed Sampling


-20

-15

-10

-5

0

5

10

0 4 8 12 16 20 24 28 32 36 40PHSLT

# 4

16

SAMPLES

PHSLT

# 8

32

SAMPLES

EXECUTEPHASELET

CALCULATIONAND PROTECTIONALGORITHMS

PHSLT

# 1PHSLT

# 2

PHSLT

# 3

PHSLT

# 5

PHSLT

# 6

PHSLT

# 7

PHSLT

# 9

PHSLT

# 10

4

Discrete Fourier Transform


v t V t

VrealN

Vkk

N

VimagN

Vkk

N

peak

k

N

k

N

( ) cos( )

( ) [ cos( )]

( ) [ sin( )]

= • +

= • • • •∑

= • − • • •∑

=

−

=

−

ω φ

π

π

22

22

0

1

0

1

5

Full Cycle Fourier Transform


-20

-15

-10

-5

0

5

10

15

20

0 64 128 192 256 320

WINDOW 1WINDOW 2

WINDOW 3

6

Phaselet Definition


• Phaselets are partial sums of the products of

the waveform samples and the sine/cosine

coefficients.

• Input signals are sampled 64 times per cycle;

protection algorithms are executed 16 times

per cycle.

• Groups of phaselets may be added together

and transformed to create a phasor.

7

Phaselet Calculation


Phaselet al C X

Phaselet aginary S X

Where

p kk p P P

p P

k

pk p P P

p P

k k

Re

Im

:

= ∑ ⋅

= −∑ ⋅

=

= ⋅ − +

⋅

= ⋅ − +

⋅1

1

C , S Sine and Cosine Coefficients

p = phaselet index: there are N / P phaselets per cycle

P = the number of phaselets per cycle

X = kth sample of the input signal

k k

k

8

-20

-15

-10

-5

0

5

10

0 4 8 12 16 20 24 28 32 36 40PHSLT

# 4

16

SAMPLES

PHSLT

# 8

32

SAMPLES

EXECUTEPHASELET

CALCULATIONAND PROTECTIONALGORITHMS

PHSLT

# 1PHSLT

# 2

PHSLT

# 3

PHSLT

# 5

PHSLT

# 6

PHSLT

# 7

PHSLT

# 9

PHSLT

# 10

Variable Window


9

Phasor Calculation


Phasor al

Phasor aginary

T nW T n W

T n W T n W

PhasorSum al

PhasorSum aginary

n

n

RR RI

IR II

n

n

Re

Im

( , ) ( , )

( , ) ( , )

Re

Im

=

•

Phaselets are converted to phasors by the following:

Where:

PhaseletSum al Phaselet aln p

p nW

P

n

Re Re=

= − +

∑1

PhaseletSum aginary Phaselet aginaryn p

p nW

P

n

Im Im= ∑= − +1

n = Phasor index (N/P) W = Window size in samples

10

Phasor Calculation


For a one cycle window, the Fourier calculation becomes:

P h a so r a lN

P h a s e l e t a l

P h a so r a g in a ryN

P h a s e l e t a g in a ry

n p

p nN

P

n

n p

p nN

P

n

R e R e

Im Im

= ⋅ ∑

= ⋅ ∑

= − +

= − +

2

2

1

1

11

Variable Window Fourier Transform


PRE-FAULT

ONE CYCLE

WINDOW

VARIABLE WINDOW

-20

-15

-10

-5

0

5

10

15

0 64 128 192 256 320

12

Mimic Algorithm


Time Domain:

Sampled Data:

IZ t I t Rd

dtI t L( ) ( ) ( ( ))= • + •

IZkI k I k

RI k I k

L( )( ( ) ( )) ( ( ) ( ))+ = + + • + + − •δ δ δ

δ2 2

13

EXAMPLES OF

ADAPTIVE PROTECTION

ALGORITHMS


14

Adaptive Polarizing Memory

Remote line end three phase faults:

Reverse zero voltage faults:

ZLZS3 PH

3 PH

ZS = 19 ZL

Vr = 0.05 Rated

Vr = 0


15


Extend memory time if:

• Voltage at the relay is less than 10% of rated.

AND

• Any distance measuring function is picked up.


16



Reset memory if:

• Voltage at the relay is greater than 10% of rated.

AND

• Distance measuring function resets.

17

Variable Reach Zone 1

Z LINE

FINAL REACH

INITIAL REACH


18

Variable Reach Zone 1

Zone 1 reach is set to 90 % of ZL.

WINDOW SIZE % OF SET REACH

1/16 Cycle 0 (can not operate)

1/8 Cycle 33%

3/16 Cycle 65%

1/4 Cycle 75%

5/16 Cycle 83%

1/2 Cycle 90%

> 1/2 Cycle 100%


19

Adaptive Reactive Unit Supervision

Reactance type distance functions require

supervision to prevent operation on normal load

flow.

The traditional approach is to use a fixed

resistive blinder, or a fixed reach mho function.


20

Adaptive Reactive Unit Supervision

X -

ZL min

X' - ZL max

Fixed

mho

Fixed

Blinder

Adaptive

mho

Reactance

Unit

Adaptive

Blinder


21

EVALUATION OF

DISTANCE RELAY

OPERATING SPEED


22

Modeled System

Protected Line

Parallel Line

Z1 = 6.0 ohms @ 86 degZ0 = 18.3 ohms @ 76 deg

Z1S = 1.5 ohms @ 86 degZ0S = 1.5 ohms @ 86 deg

Z1S = 1.5 ohms @ 86 degZ0S = 1.5 ohms @ 86 deg


23

PC Simulation Trip Times

0

5

10

15

20

0 25 50 75

% of Line

Tim

e (mS)


24

MPS Test Results

0

5

10

15

20

0 25 50 75

% of Line

Tim

e (mS)


25

The ALPS Advanced Line Protection

System gives you the protection

choices you need. Whether you’re

protecting compensated or

uncompensated lines; require single

phase tripping or three phase tripping,

with or without reclosing, its available.



26

APPLICATION

• Distance protection for EHV lines

• Series compensated lines

• High speed tripping (half cycle)

• Single and three phase tripping

Providing complete transmission line protection,

ALPS is a multi-function digital protective relay

system intended to provide distance protection for

HV or EHV transmission lines.


27

Single Line Diagram


28

PROTECTION

• Four zones of distance protection

• Pilot protection, step distance backup

• Out of step blocking and tripping

• Phase instantaneous overcurrent

• Ground instantaneous overcurrent

• Ground time overcurrent backup

• Over and under voltage functions


29

CONTROL

• Optional four shot recloser

• Configurable inputs and outputs

• Fully configurable relay logic


30

INPUTS/OUTPUTS

All contact converter inputs and all contact outputs

(except for alarms) in ALPS are configurable by the

user.

• 8 configurable inputs, or 12 for single

phase tripping

• 15 configurable outputs, or 20 for single

phase tripping


31

RMS METERING

• Current (Ia, Ib, Ic, In)

• Voltage (Va, Vb, Vc)

• Watts (3 phase)

• Vars (3 phase)

• Frequency


32

MONITORING

• fault location provided by a single ended

• fault location algorithm

• trip circuit monitor

• self test diagnostics

• event reporting of last 100 events

• fault reports

• high resolution oscillography


33

USER INTERFACE

• 20 button keypad and 4 line LCD display

• RS232 serial port on front of unit

• RS232 and RS485 ports on rear of unit

• communication software

• IRIG-B input for time synchronization


Documents

Digital Mimic · ALPS is a multi-function digital protective relay system intended to provide distance protection for HV or EHV transmission lines. ALPS Advanced Line Protection System