Linet Application To Transmission Line 6n5k25

I3CM LINET

EXPERT SYSTEM FOR DETERMINATION OF PERFORMANCE OF TRANSMISSION LINES EXPOSED TO LIGHTNING

I3CM LINET 1/13

EXPERT SYSTEM FOR DETERMINATION OF PERFORMANCE OF TRANSMISSION LINES EXPOSED TO LIGHTNING This document describes real time lightning performance determination technology, which is based on the real time data received from a Lightning Location System (LLS), such as LINET from nowcast GmbH, and real time data obtained by the remote transients recorders (I3CM). Line lightning performance is determined by means of a comparison between accurate GPS timing from LLS data and timing from the real time I3CM transient recorders.

I3CM transient monitoring system The I3CM transient recorder is to be installed in the substation secondary equipment cabinet for the transmission line or circuit of interest in order to monitor three phases’ voltages and currents.

6 BNC connectors (3 for voltages, 3 for currents)

Indoor GPS antenna connector

Power Supply connector

Network connection

I3CM transient monitoring system

Voltage probes installed on the secondary side of the voltage transformer

Clamp type current sensors installed on the secondary side of the current transformer

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This monitoring system has to measure a total of six channels, which correspond to three phase voltages and three phase currents. The voltages are measured with a voltage divider and for the currents a split core transformer is used in order to install the system without switching off the line. The 7th anaput is used for the GPS timing. Finally, since the monitoring system is connected to the secondary equipment of the substation, an acquisition speed of 20 k Samples/s/channel is sufficient.

Lightning Location System For more than two years Lightning Location System data has been available for comparison with the transient monitoring system data. This LLS data comes from the lightning detection network LINET Europe, provided by nowcast GmbH in Munich, .

Outdoor antenna of a LINET station LINET service provides the following data for each component of a lightning stroke: • • • • •

GPS Date and Time with 100 ns resolution; Latitude and Longitude coordinates of the stroke, with location error; Current amplitude of the stroke; Current polarity of the stroke; Type of discharge: Cloud-to-Ground (CG), or In-Cloud (IC).

It is important to note that this Lightning Location System provides all the parameters for each lightning stroke within a flash. Indeed, one lightning flash may contain several strokes or current components that can lead to damage on ground.

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Concept of the I3CM LINET system The concept of the system is presented in the following block diagram;

1

j

M LLS - Lightning Location System

CENTRAL SERVER

LLS

I3CM1

I3CMi

I3CM - Real time remote transient recorder I3CMN

System works in the following way: As soon as one or more transient recorders capture transients in the system (three phase voltages and currents transients), these data with GPS time stamp is immediately transferred to the central server. After reception of the captured transients, central server is searching for the real time data for the lightning activity obtained from the Lightning Location System (data which also has accurate GPS time stamp). Comparing GPS times for both data set, server detects if power system disturbance is generated or not by the fault produced by lightning stroke. If disturbance is generated by lightning, this information is immediately transferred to the with automatic geographical display of the stroke location and peak current. Stroke data is displayed on the map of the region with the display of the overhead lines routes. Position of the I3CM controllers is displayed on the same map. Substations and high voltage lines equipped with I3CM controllers are highlighted in the case of transient detection. can click on the controller position to get shapes of the voltage and current recorded by the corresponding controller. From the real time transient recording data we can determine: • • • • • • •

If fault is caused by lightning stroke or not Type of the fault Conductors on which flashover has happened Pre-fault voltages on different conductors Direction of the fault currents Short circuit currents, fault duration, if re-closing is successful or not, … Monitor power quality

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Simple monitoring example Once an event has been recorded in substation by an I3CM monitoring system, it is compared to the events recorded by other monitoring systems, as well the data provided from the Lightning Location System. One example of this monitoring and the comparison with LLS data is presented below. In this example, a transient event has been recorded in the 110 kV substation Trebinje, BosniaHerzegovina at the secondary equipment of the 110 kV line Trebinje – Herceg Novi, on 2013/11/11 at 03:12:01.9845 GMT+1 (Figure 1). It shows that the outage had occurred on all three phases, since all the three currents went to zero. Peak of the transient current is -7014 A on phase A. Voltage A (kV) Voltage B (kV) Voltage C (kV)

Current A (A) Current B (A) Current C (A) Figure 1: Measurement in substation Trebinje (top: three phase voltages; bottom: three phase currents).

As soon as this event is detected, LLS data corresponding to points of impact located in the vicinity of the line is examined within a narrow time window around the time when the transient event was recorded in the substation in order to find the closest lightning stroke component regarding date and time that might have produced that event. Table 1 presents all of the components that are candidates for this event. Table 1: Lightning stroke components from LLS data that might have produced the transient event.

LLS # 0 1 2 3 4 5

Date 20131111 20131111 20131111 20131111 20131111 20131111

Time (GMT) 02:12:01.981 02:12:01.984 02:12:02.001 02:12:02.030 02:12:02.036 02:12:02.040

Latitude Longitude 42.5592 18.4378 42.5538 18.4414 42.5633 18.4435 42.5616 18.4433 42.5573 18.4416 42.5603 18.4339

Type CC CG CG CG CC CG

Peak (kA) -10.6 -30.9 -8 -20.5 -4.3 -5.9

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Once a match has been found regarding the transients recorded in substation and lightning stroke from LLS data (LLS # 1 in this case), all of the potential components are displayed on the line map (Figure 2) in order to show which section of the line has been affected.

Real time lightning stroke position display

Cloud to Ground

Cloud to Cloud

Figure 2: LLS lightning stroke components display on the line map.

The corresponding substation and transmission lines are highlighted in real time. In this case thanks to LINET LLS data, the lightning stroke that has produced the outage occurred on 2013/11/11 at 02:12:01.984 GMT. Amplitude of the current was -30.9 kA, type of discharge is effectively Cloud to Ground.

Based on this single case presentation, with display of transient activity in real time on a map, it is possible to use the I3CM LINET system for an annual analysis of lightning activity on a particular line. This is useful to determine sections of the line that are the most affected by lightning, and therefore to calculate the line lightning performance, as well to define a maintenance strategy.

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View of different I3CM LINET software options Server software

Main view of the application with one monitored high voltage line

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Display of voltage and current measurement in substation

List of events ed in the substation

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Alarming due to ed event

Strokes from LLS database

Display of an event ed in the substation as well the corresponding lightning strokes from the Lightning Location System (LLS) provider data base which might have produced that event

Display of the transient voltage and current shapes ed in the substation for the previous event

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Detailed display of the corresponding lightning strokes from the Lightning Location System provider database which might have produced that event

Maintenance

Display of all lightning strokes from the LLS database nearby a high voltage line in one year

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Maintenance strategy based on LLS only – display of line towers with most nearby strokes

Maintenance strategy based on events ed in substation and the corresponding lightning strokes for those events in one year

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Maintenance strategy based on events and LLS – display of line towers with most nearby strokes

Additional services

Current weather conditions display along the line as well the forecast for the next 3 days (Weather data copyright to The Weather Underground, LLC)

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Copyright: I3CM Monitoring System @ Sadovic Consultant (www.sadovic.com) Lightning Location System data © nowcast GmbH (www.nowcst.de) Map data © OpenStreetMap contributors Weather data © The Weather Underground, LLC

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