2. Technical Panel Session. Sunday January 11, 2015. DC System Failure Modes IEEE PES SBC Winter Meeting. January 11 – 15, 2014. New Orleans, LA Part 3

3. Typical DC Power System IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA DC Distribution.  Distribution is the point at which the power is interfaced with the loads.  Provides over-current protection for the load.  Can be fuses or circuit breakers. Fuses are usually preferred in wire-line telecom, breakers in wireless.  Can be a single point of failure  Where the load equipment has two inputs or power supplies for redundancy there is a need for two power feeds to each load. This is known as A / B Feeds

4. Typical DC Power System IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA Typical Main DC Distribution Bay, also called a Main Distribution Fuse Bay (MDFB) or Main Distribution Circuit Breaker Bay (MDCBB) for Large System.  Can feed supplemental or remote bays.  Usually available from 600-10,000 amps in a wide range of configurations allowing for customization.  The systems are configured to accept a wide range of standard distribution and alarm panels.  Circuit breaker panels can range from a 10 position, 0-100 amp panel to a 300-600 amp panel equipped with a 600 amp shunt.  Distribution fuse panels range from a 20 position, 0-5 amp panel to 600 amp fuse/switch units.

5. Typical DC Power System  Fuse protection available in current ratings of 0-30, 31-60 and 61-100 amps.  Circuit breaker protection available in current rating of 1-100 amps. IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA Typical Primary Distribution for medium size power system

6. Typical DC Power System IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA Typical BDFB or BDCBB also called a Remote Bay. Serves as a secondary power distribution center for - 48 V DC power delivered from the main DC Power Board to the load equipment.  Fuse protection utilizing TPS, TPA and TPL fuses protects circuits ranging from 0-150 amps.  Circuit breaker protection LEL plug-in breakers available in current ratings of 1-150 amps.  Multiple circuit breaker types. Options range from bolt-in to plug-in

7. Typical DC Power System IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA Secondary Battery Distribution Fuse Bays ranging in size from 1200 amps to about 20 amps

8. Typical DC Power System IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA GMT Fuses  Fast acting fuses that have a visual spring and alarm activating capabilities.  Color-coded flags designate ampere rating.  Fuses can be easily replaced without the use of insulated tools. Typical GMT distribution panel

9. Typical DC Power System IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA Typical Telecom Fuses Type TPL, TPN and TPS Type 70 Telecom Fuses

10. Typical DC Power System IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA Telecom Distribution Fuses TPL, TPN and TPS fuses are available from 1 to 800 amperes and rated at 170VDC with an interrupting rating of 100,000 amps. The telecom fuses have high current limiting capabilities to provide a better degree of circuit protection. TPL – 70 - 800 Amps. 170 VDC - 100kA AIC TPN – 1 - 600 Amps. 170 VDC - 100kA AIC TPS – 1 - 70 Amps. 170 VDC - 100kA AIC Typical Telecom Fuses Type TPL, TPN and TPS

11. Typical DC Power System IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA DC Distribution Circuit Breakers They should have the following features:  DC Rated for 25% above nominal DC voltage.  Alarm contacts or trip indication. They are usually available in the following types depending upon size and capacity,  Bolt-in  Plug-in  Snap-in

12. Typical DC Power System IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA Typical DC rated Circuit Breakers Plug-in (banana) type Bolt-in type Ganged Bolt-in type Snap-in type

13. Typical DC Power System IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA Inverters. An inverter is the opposite of a rectifier, it converts a DC voltage to AC.  Older inverters are of the SCR design.  Modern inverters are of a switch-mode design and are usually modular and parallelable.  The usually incorporate a static transfer switch.  They can be permanently on-line with a reverse transfer switch (transfer to utility in case of inverter failure). This is the Preferred method.  They can be off-line with transfer to inverter only upon utility failure.

14. Typical DC Power System Typical Large Inverter Systems. Can be single phase or three phase output. IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA Three Phase Modules Single Phase Modules Static Switch Control

15. Typical DC Power System Typical Small or stand-alone inverter units IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA

16. Typical DC Power System DC Power System Monitoring and Control Features: IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA  - Equipment Alarms  - System Alarms  - System Controls  - Remote Access

17. Typical DC Power System DC Power System Monitoring and Control. Control Features: IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA  - Float / Equalize Voltage  - Marginate Low (battery self-test feature)  - Metering  - Temperature Compensation  - Load Disconnects  - Low Voltage Disconnect  - Date/Time and housekeeping settings.  - Security

18. Typical DC Power System DC Power System Monitoring and Control Equipment Alarms IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA  - Rectifier Fail  - AC Fail  - Over Current  - Over Temperature  - High Voltage  - Low Current Rectifiers Converters Inverters  - Converter Fail  - Inverter Fail  - Bypass Not Available

19. Typical DC Power System DC Power System Monitoring and Control. Power Bay Alarms IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA  - High Voltage 1  - High Voltage 2  - Low Voltage 1  - Low Voltage 2  - 2 Rectifier Fail  - 2 Converter Fail  - Fuse / Circuit Breaker  - Major  - Minor GeneratedConsolidated

20. Battery Condition Analysis DC Systems

21. IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA From a battery analysis perspective the parameters that can be monitored are the same irrespective of the application. The primary difference is the run time required. Using limit based analysis to monitor the static parameters Voltage Current Temperature There are two basic ways to analyze a battery system: or Activating the battery either by ohmic testing or discharge testing and using trend analysis over a period of time to identify any deterioration

22. Battery Condition Analysis DC Systems IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA Some of the power system manufacturers particularly those intended for Telecom applications actually incorporate limited battery monitoring into their system controllers. They reduce the charge voltage to a lower level which will allow the battery to take up the load and discharge till it reaches the reduced voltage. The most basic systems simply monitor the system voltage and current during the test. Other systems monitor the midpoint voltage and compare the voltages on each half of the string to detect a low voltage battery unit Typically to measure the unit voltages and temperatures requires an additional module which will increase the system cost

23. Battery Condition Analysis DC Systems IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA All parameters will eventually change and trigger a limit based alarm. Some just take longer than others 22 nd August this unit goes open circuit 3 rd of September low voltage alarm

24. Battery Condition Analysis DC Systems IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA Required reserve time 15 minutes System Voltage Discharge Testing based on system level performance can be misleading

25. Battery Condition Analysis DC Systems IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA String 5 Unit 6 Individual Unit Voltages Strings 1 thru 5 14.2 minutes into the discharge

26. Battery Condition Analysis DC Systems IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA String 5 Unit 6 Individual Unit Voltages Strings 1 thru 5 14.2 minutes into the discharge

27. Battery Condition Analysis DC Systems IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA String 5 Unit 6 4.067 V String 5 Unit 4 7.178 V String 2 Unit 8 11.336 V Individual Unit Voltages Strings 1 thru 5 What a difference three and a half minutes makes 17.5 Minutes end of Discharge

28. Battery Condition Analysis DC Systems IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA Unit 6 String 5 11.720V Unit 4 String 5 8.496V

29. Battery Condition Analysis DC Systems IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA String 1 Unit 13 String 1 Unit 6 Impact of a Discharge Test

30. Battery Condition Analysis DC Systems IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA String 2 Unit 15 String 2 Unit 20

31. Battery Condition Analysis DC Systems IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA Any Questions ? THANK YOU…

32. Technical Panel Session. Sunday January 11, 2014 DC System Failure Modes General Discussion IEEE PES SBC Winter Meeting. January 11 - 15, 2014. New Orleans LA