Modern Trends/Developments in Protection & Modern Concepts Used for Line Protection with M1 & M2 Relays Training on Power System Protection ERPC 11-15 May, 2015 Dr. R. Nagaraja Managing Director PRDC
Dec 19, 2015
Modern Trends/Developments in Protection &
Modern Concepts Used for Line Protection with M1 & M2 Relays
Training on Power System Protection ERPC 11-15 May, 2015
Dr. R. NagarajaManaging Director
PRDC
Substation and Interface level
Wide Area Protection
Testing Environment
Setting calculation and storage
Disturbance Analysis
Line Protection - Trends
Agenda
Substation and Interface Level
Substation wiring cost is being reduced drastically with IEC 61850
Interoperability between product and applications
Overall substation management and efficiency improvementGoose messaging is being used to achieve better adaptability in settingSetting and relay operation waveform upload/download remotely
Substation Level
Source : ABB Brochure
Optical CT usage has improved the measurement/sensing and minimized the CT
saturation related errors
Wide Area Measurement and Protection
Distance Protection
Zone 1 = 85% of AB = 0.85*10 = 8.5 ohm
Zone 2 = AB+50% of BC (shortest line) =10+0.5*10 =15 ohm
Zone 3 = AB+BC+20% of CD (longest line) = 10+10+0.2*10 =22 ohm
A B C D
E
F
R10 Ω 10 Ω 10 Ω
20 Ω
5 ΩZone 1
Zone 2
Zone 3
Distance relay zone settings
Multi-terminal LinesA B
C
D
R10 Ω 10 Ω
ET
10 Ω
10 Ω
10 Ω
IA IB
Ic
A
TBBATA
R
R
I
)Z*I()Z*(I
I
V
A
TBCAATA
R
R
I
Z*)II()Z*(I
I
V
A
CTBTBAT
R
R
I
IZZZ
I
V
A
CTBTBAT1 I
IZZZK1 Zone
BD2A
CTBTBAT Z*K
I
IZZZ2 Zone
DE3BDA
CTBTBAT Z*KZ
I
IZZZ3 Zone
Multi-terminal Lines
Without infeed( Ic=0)
With infeed( Ic=IA)
Weak infeed( Ic=0.5*IA)
Strong infeed( Ic=2*IA)
Zone 1 (Ω) 17 25.5 21.25 34
Zone 2 (Ω) 25 35 30 45
Zone 3 (Ω) 32 42 37 52
Out of step relay
Traditional relays use zones to determine whether electromechanical swing will lead to instability or not.
Out of step relay
Large number of simulation need to be carried out to determine relay settings.
Conventional settings are unsatisfactory and results in mis-operation because system changes quickly and tested swings are different from actual.
Adaptive settings are required to cope up with such problem.
Adaptively changing the timer settings.
Adaptive Zone settings.
New approach is suggested using equal area criteria.
Implemented on Florida-Georgia interface project undertaken by Virginia Technology.
Out of step relay
Pm1
Y10
Pm2
Pe1 Pe2
Y20
11 δE 22 δE Y12
γ)sin(δPPPdt
δdM maxcm2
2
rotors twoof inertia ofmoment are M and M and where 2121
21
21
MM
M*MM
21
m21m12m MM
PM-PMP
21
2222111
212
c MM
GEM-GEMP
2/)MM(
tan)MM(
21
1221
)M(M
)cos(2θM2MMMYEEP
21
12212
22
11221max
Out of step relay
Accelerating area must be smaller than decelerating area for system to be transient stable.
Equal area criteria
Back up Protection
Load encroachment
Back up zones of distance relay are prone to tripping due to load encroachment.
Modification in relay characteristics is required.
Same can be achieved by using phasor measurement unit.
Back up Protection
Assume zone 3 of relay A has picked up.
Determine for any zone 1 fault in other stations using PMU.
If none of them exist restrain zone 3 of relay since it might have picked up due to loadability in the system.
A
Event Analysis and Oscillation Monitoring Schemes using PMU data
Distance Relay Concerns• Parallel line
operation• Mutual coupling • In-feed • Power swing and
load encroachment
Event Analysis and Oscillation Monitoring Schemes using PMU data
Need Introduction of PMU has open avenues for various power system applications
Major challenge is to analyze the group of PMUs and correlate the data with system events
Utilizing the higher sampling data to analyze more critical system behavior such as low frequency oscillations
Justification The scheme focuses on generic architecture for PMU applications.
Event analysis is an important task which can help the data to segregate into Disturbance data or Ambient data.
Testing Environment
Testing Trend
Steady-state calibration
Dynamic-state simulation
Transient simulation
End-to-end testing.
Source: Doble Project at PRDC
Source: Kinetrics Interoperability Lab
Use of Real Time Digital Simulation Environment for special protection systems
(SPS) and critical lines distance scheme testing is highly recommended
Setting Calculations & Storage
Protection Database Management System
Protection Setting Calculation Engine
Protection Suite Components
Bus-Branch Model to
Bus-Breaker Model
Protection Suite Components
22
Grid Disturbance
Protection LayerBest Operational Practices
System Planning
Special Protection Systems (SPS)
It is not easy to achieve Grid Collapse!!!
Specific Action following an outage/disturbance
Fast acting and generally without any time delay
Applicable for tie lines tripping, HVDC link tripping, major generation
trippingSaves the system from complete
collapse
23
Hard wired scheme
• On tripping of a specific element/breaker other elements are tripped to get load/generation relief
• Generally ends up in more load shedding or generation curtailment
• Optimal action is not ensured
• At times may not get any relief
Intelligent System
• Ensures optimal load/generation tripping
• Needs system digital and analog information
• Network topology processing program
• Dynamically computes the load or generation to be tripped for any breaker tripping
SPS Implementation - Types
Simulation Environment
Improves the protection settings
Simulates various operating conditions
Helps to re-construct and perform post-mortem analysis
Design of out-of-step and under frequency load shedding schemes
Disturbance Analysis
Automation in Fault Disturbance Data Collection and Analysis
AFAS
Report Manager
Data Collector
Processed File Storage
Inputs from all locations
Server with Database and Engines
Queries from Users
Outputs
DPR, DFR, SCADA ...
Centralized Deployment of Fault Analysis System
Levels of analysis
System Level
Unit Level
Bay Level
Station Level
Station 1
Station 2
Station 3
Station 4
Protection Function
level
Probable Architecture of Fault Analysis System
System ManagerUser Access ManagerConfiguration ManagerCOMTRADE ViewerEngineLoggersReport GeneratorWeb InterfaceOffline Analysis
Fault Analysis System Modules
COMTRADE Viewer
Distance Relay Contour
Case study of AFAS
Power Research and Development Consultants Pvt. Ltd.
Waveform of Phase R Current
Inferences
· Single line ground fault detected
·Fault distance of 286.54 km
·Successful auto reclosure having dead time of 1.09 s
·CT saturated during fault
·CVT is healthy
·Relay operation within limits
Inferences
· Single line ground fault detected
·Fault distance of 286.54 km
·Successful auto reclosure having dead time of 1.09 s
·CT saturated during fault
·CVT is healthy
·Relay operation within limits
System Performance over the period and KPI tracking
Additional Benefits of AFAS
Algorithm level improvement
Improved Technique for Fault location computation and identifying cause of Fault
Need of improved scheme Digital filters are used to compute fundamental component of voltages and currents.
Discrete Fourier transform (DFT) is a popular filtering technique.
The response time of DFT is around one cycle, which is bound to increase if the input is non sinusoidal.
Power system computation can have errors due to variation in filter output.
Information about the cause of fault can render assistance to power system engineers which is not been focused presently
Justification Scheme based on Prony analysis is effective for short duration fault
Prony analysis determines the components at actual system frequency unlike DFT which always computes at fixed nominal frequency
Algorithm to identify cause of fault will be an additional information to the system operators and maintenance crew for taking better decisions.
36
Short Duration Fault Short duration faults are defined as the faults that are cleared within two power frequency cycles.
If the faults are cleared fast, the current may not reach its faulted steady state value and the voltage may not drop to its faulted steady-state value.
37
Case Study For 2 bus system, SLG fault is simulated at 95km and 0.1s. Fault location is computed as:
Im refers to imaginary part of the quantityV is phase voltage for the faulted phase ‘x’ I is line current for the faulted phase ‘x’ I0 is the zero sequence current k0 is zero sequence compensation factor Z1 is positive sequence impedance of line
Fault Location
Observations: 1) Fault location value is dependent on fault clearing time.2) Higher the fault clearing time, more accurate is fault location value.
Fault clearing duration
Fault Location from DFT (km)
Reported Minimum Maximum Variation
1 Cycle (0.02s) 92.41 -1427.22 4358.57 5785.79
2 Cycle (0.04s) 93.61 86.05 103.44 17.39
3 Cycle (0.06s) 94.22 89.16 100.12 10.96
4 Cycle (0.08s) 94.54 91.23 98.14 6.91
5 Cycle (0.10s) 94.71 92.58 96.93 4.35
6 Cycle (0.12s) 94.81 93.45 96.19 2.74
50 Cycle (1.00s) 94.96 94.96 94.96 0.00
New Scheme
Observations: 1) Fault location is almost constant for different fault clearing time2) The value obtained are very near to expected value of 95 km
No
Any mode with frequency
variation of +/-5% from nominal
value?
Compute Fault location for the identified mode
Yes
Stop
Compute modes using Prony analysis
Consider voltage & current data for fault period and System frequency
Start Fault clearing duration Fault Location (km)
1 Cycle (0.02s) 94.862 Cycle (0.04s) 94.943 Cycle (0.06s) 94.95
50 Cycle (1.00s) 94.95
Fault Signature
Insulator failure
Tree encroachment
Fault Signature
Lightning strike
Proposed logic
Signature Correlation function Correlation function can be used to determine fault initiation time and fault
classification Pre-fault data of faulted phase can be analyzed for small excursions as
Logic to identify rise in current
Parameters Case-1 Case-2
Imax1 (kA) 4.94 8.89
Imax2 (kA) 8.61 7.67
Imax3 (kA) 8.67 6.88
Imax1 < Imax2 Satisfied Not satisfied
Imax2 < Imax3 Not checked Not satisfied
Cause of fault Tree encroachment Lightning strike
Cable protection trend
No auto-reclosure for cable fault
400 kV line protection trend
Discussions
Thank You