Fault Level Monitor

Ken Lennon

LCNF Conference

25th October 2012

• Process of product development and the need for fault level visibility

• Basic principles behind the Fault Level Monitor (FLM)

• Fault level monitor trial results

Scope of Presentation

• Evolutionary change in system generation and load (Smart Grids - LCN).

• DNO’s have a duty to manage network fault levels, system stability and power quality.

• Becoming more difficult to programme computer models accurately to predict fault levels .

SPEN’s proactive approach to the issue

• Identified fault level monitor requirements

• Approached Outram Research Ltd & Led development of FLM product

• Provided data, computer model analysis for product development and feedback

• Help pioneer the product and completed field evaluation

So why is there a need for measured fault level visibility?

Basic principles

Upstream EventsE.g. Transformer Tap Changer taps down

• Voltage & Current Dips at the FLM position

13:27:2102/09/12 13:27:2602/09/1227:22 27:23 27:24 27:25Time 5 seconds (mm:ss)345

Value (?)

170.0175.0180.0

AC Current (Aac)

10.70010.80010.900

Voltage (kV)

MaximumMinimumAveragekV RMS of Vab 10.909 10.634 10.896kV RMS of Vcb 10.951 10.795 10.941 MaximumMinimumAverageAac RMS of Ia 182.2 165.7 178.6? on Ch 13 4 4 4

• FLM measures Motor Response and calculates down stream Motor Contribution

Downstream EventsE.g. Downstream Load changes

• Current Rises and the Voltage Dips

15:10:47.601/09/12 15:10:49.701/09/1248.0 48.2 48.4 48.6 48.8 49.0 49.2 49.4Time 00:00:02.1000 (ss)180.0182.0184.0186.0188.0

AC Current (Aac)

10.94010.96010.980

Voltage (kV)

MaximumMinimumAveragekV RMS of Vab 10.944 10.926 10.940 MaximumMinimumAveragekV RMS of Vcb 10.985 10.965 10.980 MaximumMinimumAverageAac RMS of Ia 189.1 179.6 181.5

• FLM measures Source Response and calculates Upstream Source Impedance

Basic principles

90mS RMS

10mS Pk

Basic principles

Two FLM’s were installed at a Primary substation.

The substation feeds a 6.3kV customer via two 6.3kV feeder cables.

FLM’s were installed at the metering position as shown in the photograph.

The fault level results obtained were very promising.

Real World Trial Results

Customer Feeder 1 Customer Feeder 2

12.9kA

25.6kA 26.7kA

13.2kA

*Model Result 10mS Peak = 26.1 kA

*Model Result 90mS RMS = 12.9 kA

Real World Trial Results