where:
●
DQ
H,R
= winding hottest spot rise over top oil temperature at rated load. This parameter is set by the user
●
K
U
= the ratio of actual load to rated load
●
m = winding exponent (Winding exp m setting)
2.2.3
THERMAL STATE MEASUREMENT
D
Hot spot temperature, Top oil temperature and ambient temperature are stored in non-volatile memory. These
measurements are updated every power cycle. The thermal state can be reset to zero by any of the following:
●
The Reset Thermal cell under the MEASUREMENT 3 COLUMN on the front panel
●
A remote communications interface command
●
A status input state change.
The top oil temperature, hot spot temperature, ambient temperature and pre-trip time left are available as a
measured value in the MEASUREMENT 3 column.
If you need a more accurate representation of the transformer thermal state, you can use temperature monitoring
devices (RTDs or CLIO), which target specific areas. For short period overloads, RTD, CLIO and overcurrent
protection techniques provide better protection.
The PSL provides a signal indicating that the transformer is de-energised (TFR De-energised). This signal is
asserted when all the circuit breakers are open. In this case, the transformer no-load losses are not considered. As
a result, the top oil and hottest spot temperatures are equal to the ambient temperature when the monitored
current is zero. If this signal is removed, the top oil and hottest spot temperatures are not equal to the ambient
temperature even when the monitored current is zero. In this case the top oil and hottest spot temperatures will
increase according to the described equations.
2.3
APPLICATION NOTES
2.3.1
ALSTOM RECOMMENDATIONS
Monitored Winding
You can set the monitored winding to
HV
,
LV
,
TV
or
Biased Current
. We recommend setting it to
Biased
Current
to provide an overall thermal condition for the transformer.
Ambient Temperature
Ambient temperature is an important factor when determining the load capability of a transformer, because you
add it to the temperature rise due to loading to determine the operating temperature. IEEE C57.91-1995 states
that transformer ratings are based on an average ambient temperature of 30°C.
The Ambient T Source setting defines whether the ambient temperature should be set to an average level or
measured directly using a CLI or RTD input. When measuring the ambient temperature, it should be averaged over
a 24-hour period.
Top Oil Temperature
The Top Oil T source setting defines whether the Top Oil temperature is calculated or measured.
We recommend setting the rated load (Rated Current) to 1.0 pu.
2.3.2
IEEE RECOMMENDATIONS
Winding Exponent
IEEE C57.91-1995 suggests the following winding and oil exponents.
P64x
Chapter 7 - Transformer Condition Monitoring
P64x-TM-EN-1.3
147
Summary of Contents for P642
Page 2: ......
Page 18: ...Contents P64x xvi P64x TM EN 1 3 ...
Page 24: ...Table of Figures P64x xxii P64x TM EN 1 3 ...
Page 25: ...CHAPTER 1 INTRODUCTION ...
Page 26: ...Chapter 1 Introduction P64x 2 P64x TM EN 1 3 ...
Page 36: ...Chapter 1 Introduction P64x 12 P64x TM EN 1 3 ...
Page 37: ...CHAPTER 2 SAFETY INFORMATION ...
Page 38: ...Chapter 2 Safety Information P64x 14 P64x TM EN 1 3 ...
Page 50: ...Chapter 2 Safety Information P64x 26 P64x TM EN 1 3 ...
Page 51: ...CHAPTER 3 HARDWARE DESIGN ...
Page 52: ...Chapter 3 Hardware Design P64x 28 P64x TM EN 1 3 ...
Page 87: ...CHAPTER 4 SOFTWARE DESIGN ...
Page 88: ...Chapter 4 Software Design P64x 64 P64x TM EN 1 3 ...
Page 98: ...Chapter 4 Software Design P64x 74 P64x TM EN 1 3 ...
Page 99: ...CHAPTER 5 CONFIGURATION ...
Page 100: ...Chapter 5 Configuration P64x 76 P64x TM EN 1 3 ...
Page 121: ...CHAPTER 6 TRANSFORMER DIFFERENTIAL PROTECTION ...
Page 122: ...Chapter 6 Transformer Differential Protection P64x 98 P64x TM EN 1 3 ...
Page 165: ...CHAPTER 7 TRANSFORMER CONDITION MONITORING ...
Page 166: ...Chapter 7 Transformer Condition Monitoring P64x 142 P64x TM EN 1 3 ...
Page 189: ...CHAPTER 8 RESTRICTED EARTH FAULT PROTECTION ...
Page 190: ...Chapter 8 Restricted Earth Fault Protection P64x 166 P64x TM EN 1 3 ...
Page 215: ...CHAPTER 9 CURRENT PROTECTION FUNCTIONS ...
Page 216: ...Chapter 9 Current Protection Functions P64x 192 P64x TM EN 1 3 ...
Page 249: ...CHAPTER 10 CB FAIL PROTECTION ...
Page 250: ...Chapter 10 CB Fail Protection P64x 226 P64x TM EN 1 3 ...
Page 259: ...CHAPTER 11 VOLTAGE PROTECTION FUNCTIONS ...
Page 260: ...Chapter 11 Voltage Protection Functions P64x 236 P64x TM EN 1 3 ...
Page 274: ...Chapter 11 Voltage Protection Functions P64x 250 P64x TM EN 1 3 ...
Page 275: ...CHAPTER 12 FREQUENCY PROTECTION FUNCTIONS ...
Page 276: ...Chapter 12 Frequency Protection Functions P64x 252 P64x TM EN 1 3 ...
Page 286: ...Chapter 12 Frequency Protection Functions P64x 262 P64x TM EN 1 3 ...
Page 287: ...CHAPTER 13 MONITORING AND CONTROL ...
Page 288: ...Chapter 13 Monitoring and Control P64x 264 P64x TM EN 1 3 ...
Page 306: ...Chapter 13 Monitoring and Control P64x 282 P64x TM EN 1 3 ...
Page 307: ...CHAPTER 14 SUPERVISION ...
Page 308: ...Chapter 14 Supervision P64x 284 P64x TM EN 1 3 ...
Page 322: ...Chapter 14 Supervision P64x 298 P64x TM EN 1 3 ...
Page 323: ...CHAPTER 15 DIGITAL I O AND PSL CONFIGURATION ...
Page 324: ...Chapter 15 Digital I O and PSL Configuration P64x 300 P64x TM EN 1 3 ...
Page 336: ...Chapter 15 Digital I O and PSL Configuration P64x 312 P64x TM EN 1 3 ...
Page 337: ...CHAPTER 16 COMMUNICATIONS ...
Page 338: ...Chapter 16 Communications P64x 314 P64x TM EN 1 3 ...
Page 397: ...CHAPTER 17 CYBER SECURITY ...
Page 398: ...Chapter 17 Cyber Security P64x 374 P64x TM EN 1 3 ...
Page 415: ...CHAPTER 18 INSTALLATION ...
Page 416: ...Chapter 18 Installation P64x 392 P64x TM EN 1 3 ...
Page 431: ...CHAPTER 19 COMMISSIONING INSTRUCTIONS ...
Page 432: ...Chapter 19 Commissioning Instructions P64x 408 P64x TM EN 1 3 ...
Page 460: ...Chapter 19 Commissioning Instructions P64x 436 P64x TM EN 1 3 ...
Page 461: ...CHAPTER 20 MAINTENANCE AND TROUBLESHOOTING ...
Page 462: ...Chapter 20 Maintenance and Troubleshooting P64x 438 P64x TM EN 1 3 ...
Page 477: ...CHAPTER 21 TECHNICAL SPECIFICATIONS ...
Page 478: ...Chapter 21 Technical Specifications P64x 454 P64x TM EN 1 3 ...
Page 507: ...APPENDIX A ORDERING OPTIONS ...
Page 508: ...Appendix A Ordering Options P64x P64x TM EN 1 3 ...
Page 512: ...Appendix A Ordering Options P64x A4 P64x TM EN 1 3 ...
Page 513: ...APPENDIX B SETTINGS AND SIGNALS ...
Page 515: ...APPENDIX C WIRING DIAGRAMS ...
Page 516: ...Appendix C Wiring Diagrams P64x P64x TM EN 1 3 ...
Page 590: ......
Page 591: ......