Download Experience with On line PD Measurements on By James Cowling Martec

Experience with On line PD Measurements on
MV Motor Windings in South Africa
By James Cowling
Martec
Martec Approach
• Represent
– EDI
– Eaton
• On Line PD Monitoring Systems
– Monitors and Predictive relays
– Sensors
• 80pF Capacitive Couplers (vendor neutral)
• Stator Winding RTD’s
• RFCT’s
Basic Sensors
RTD
Module
RFCT
Coupling
Capacitor
Partial Discharge Monitor
Up to 90 PD
channels
Cables
Switchgear
Motors
Generators
Bus Duct
PD Quantities
• PD Magnitude (mV or pC)
– Size or the volume of the defect
• Pulse Count (PPS)
– Number or Growth of defects
• PD Intensity/Power (mW)
– Destructive Power of the PD events
• PD Signature
– Phase of the Defect
– Type of Defect
Phase Resolved Data
• Phase to Ground
• Phase to Phase
• PD Signature
Fingerprint Analysis
Partial Discharge
between insulation and
HV (delamination from
copper)
Pulse magnitudes on
positive half wave is
higher than on negative.
(Negative Preference)
Fingerprint Analysis
Balance of Polarity Pulses: Internal
Insulation Delamination
Fingerprint Analysis
Partial Discharge
between insulation and
ground (Probably Slot
Discharge)
Pulse magnitudes on
negative half wave is
higher than on positive.
(Positive Preference)
Negative Temp
Coefficient
Positive Temp
Coefficient
Trending
9,5MW 11kV Synchronous
9,5MW 11kV Synchronous APRG
Why Couplers and RTD’s
• 17MW 11kV Motor VSD
11MW 11kV Compressor AFPW 1
11MW 11kV Compressor AFPW 1
17,15MW 11kV Compressor Motor
11kV 17MW DOL Compressor
6,6kV Motors
• Martec requested to demonstrate equipment
• 3 Identical 9MW Motors
• Single PD Measurements with 80pF Couplers
only.
Motor 3 PDI and Qmax Readings
Motor 3 NQ Graphs
Motor 3 3D Graphs
Motor 2
Motor 1 PDI trend
Motor 1 PR Graphs
Motor 1 PR Graphs
Motor 1 PR Graphs
20MW Generator With Noise
20MW Generator with Noise
Noise Reduced by RFCT
27MW 11kV Motor
12MW 11kV Motor
12MW 11kV Motor
Design Deficiency?
Tan Delta Results 49MVA Generator
Power Factor Tip Up for TG1
0.7
0.66
0.6
Phase
A
0.57
% Power Factor
0.5
0.50
0.44
0.4
0.39
Phase
B
0.35
0.3
0.2
Phase
C
0.1
0
2
4
5
6
KV Applied
7
8
Case Study - 49 MVA Generators
Before Repair
After Repair
Case Study - 49 MVA Generators
A & C Phase Connection Ring
Need more space
110MVA 10,5KV Generator
LOSS TANGENT / CAPACITANCE vs VOLTAGE
600
Tan Delta (1e-4)
50 0
•
400
Turbine End
300
200
10 0
0
2 10 0
4200
6300
8400
10 50 0
Voltage (Volts)
LOSS TANGENT / CAPACITANCE vs VOLTAGE
600
Tan Delta (1e-4)
50 0
•
400
300
200
10 0
0
2 10 0
4200
6300
Voltage (Volts)
8400
10 50 0
Exciter End
PD Data Turbine End
PD Data Exciter End
11kV Generators
•
No Sensors RTD sensor installed temporarily
Couplers and RTD sensor installed
Humidity and Temperature
11MW Compressor Motor
Effects of Humidity
The End
• Questions