1HSA 801 080-15en EXCOUNT-II Users guide EFTER KORR med … · 2. Before installation 2.5 Installation of battery in the sensor The sensor’s power sources are the in-built solar

11HSA 801 080-15en EXCOUNT-II Users Manual

User’s manual

EXCOUNT-II

2 1HSA 801 080-15en EXCOUNT-II Users Manual

Legal disclaimerAny responsibility or liability for loss or damage in connection with the use of this product and the accompanying documentation is disclaimed. The infor-mation in this document is furnished for informational use only, is subject to change without notice, may contain errors or inaccuracies, and represents no commitment whatsoever.

Declaration of ConformityHereby, ABB Power Technology Products, declares that this EXCOUNT-II system is in compliance with the essential require-

ments and other relevant provisions of Directive 1999/5/EC.

Federal Communications Commission StatementThis device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions:(1) this device may not cause harmful interference, and(2) this device must accept any interference received, including interference that may cause undesired operation.

WARNING!Changes or modifications not expressly approved by the party responsible for compliance could void the user’s authority to operate the equipment.

NOTE! This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is so operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instruction manual, may cause harmful inter-ference to radio communications. Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be requi-red to correct the interference at his own expense.

Trademark acknowledgementsWindows 95, 98, ME, NT4, 2000 and XP are registred trademarks of Microsoft Corporation.

Important information


Safety information

Key to the symbols

This symbol is a visual notice to avoid mistakes which can result in damage of the material and/or no function of the surge arrester monitor EXCOUNT-II. Read the text carefully and if you don’t understand do not proceed.

Serious material damage, severe personal injury and/or death can be the result of not following the information given beside this symbol. Read the text carefully and if you don’t understand do not proceed.

Safety instructionsDo not connect the Transceiver to other voltage sources than a standard 9 volt battery type 6LR61/PP3Ensure that the battery is connected correctly. The Transceiver contains a radio transmitter and receiver which must not be used where the use of radio transmit-ters or other electronic devices is prohibited.

WARNING!All work related to the fitting, mounting, assembly or handling of EXCOUNT-II sensors and the surge arresters shall be made with disconnected and earthed conduc-tors. Follow all regulations and rules stated by internatio-nal or national safety regulations.

Normally, the EXCOUNT-II sensors and the surge arres-ters operate at a high voltage. Therefore they must be installed in such a way that only qualified personnel has access to them.


Table of contents

Section Subject Page- Important information 2- Safety information 3

1. Introduction1.1 Sequency of installation 61.2 EXCOUNT-II measuring principle 7

2. Before installation2.1 Inspection upon arrival 102.2 Tools for assembly 102.3 Insert the 9V battery in the transceiver 102.4 Pre-installation 102.5 Installation of battery in the sensor 122.6 EXCOUNT-II software 132.7 First time administration of the sensors 14

3. Sensor installation3.1 Note the sensor ID number 183.2 Common installation alternatives 183.3 Reference measurement 183.4 Installation of sensor alternative 1 193.5 Installation of sensor alternative 2 20

4. Using the transceiver4.1 Sychronization of the clocks 224.2 Range of communication 234.3 Your body affects the signal strength 234.4 Direction of the transceiver antenna 234.5 Direction of the sensor antenna 244.6 Transceiver buttons 254.7 Transceiver symbols 264.8 Flowchart, make measurements 27

5. Transceiver menus 306. Surge arrester monitoring theory

6.1 Introduction 366.2 Surge counting 366.3 Leakage current measurements 38

7. Radio transmission protocol 488. Technical data 529. Disposal 5610. Transceiver error codes 5811. Index 62


Table of contents

Introduction

Section 1


1. Introduction

EXCOUNT-II is an advanced surge arrester monitor for effecti-vely, reliably and safety monitoring and recording surges on high voltage electrical networks.

EXCOUNT-II incorporates a sensor, which is mounted on the surge arrester, a transceiver, for remote reading and a PC-program (Win-dows 95/98/2000/ME/NT and XP).

This users manual describes the functions of EXCOUNT-II to give you total control over surge monitoring.

Please visit www.abb.com/arrestersonline for more information about EXCOUNT-II and also to download the latest version of the PC-pro-gram.

1.1 Sequence of installationAs a quick guide, the respective procedure in the below table should be followed for safe and correct installation of the EXCOUNT-II.

Procedure Section

Read the safety instructions carefully 1

What to do before installation 2

How to install the sensors 3

Guide to using the transceiver 4


1. Introduction

1.2 EXCOUNT-II measuring principle

Figure 1.2.1The principle of measuring with EXCOUNT-II

The sensor is mounted on the surge arrester in series with the earth conductor. It is important that the surge arrester is insulated from the ground with an insulating base. The sensor registers the number of discharges, categorizes and records the amplitudes of the surges together with their date and time and measures the leakage current. As an option, resistive leakage current can also be measured.

The measuring data is transfered to the hand held transceiver by radio communication.

The information from the hand held transceiver is transfered to a PC via RS232 cable.

Statistical analysis can be undertaken in the PC via the EXCOUNT-II software.

RS232 Cable

Transceiver

Sensor

EarthCable

Surge Arrester

Insulatingbase

Radiowaves

PC (computer with Windows95/98/2000/ME/NT/XP installed)



Before Installation

Section 2


2. Before installation

2.1 Inspection upon arrivalUpon arrival it is important that the cases are inspected and the contents checked against the packing list which is attached to each case. Any shortage or damage should be reported immediately to the insurance and/or ABB representative and not later than 30 days from the arrival of the goods. ABB cannot take responsibility for shortages or damages not reported within this time period.

Verify that the following items are present together with this manual:

• Transceiver• Data cable (RS232)• CD with software• 9V battery• Philips screwdriver

If the contents are to be stored for a long period of time prior to use, they should be kept dry and indoors.

2.2 Tools for assemblySpecial instruments or tools are not required for installation of the EXCOUNT-II sensor. For convenience, a philips screwdriver is provi-ded for fitting of the 9V battery in the transceiver.

2.3 Insert the 9V battery in the transceiverOpen the battery compartment on the rear of the transceiver using the delivered screwdriver. The compartment cover is locked with a single philips-head screw. Insert the battery and ensure the correct polarity. Replace the cover and firmly tighten the screw.

2.4 Pre-installationPrior to installation of the EXCOUNT-II sensor onto the surge arrester, the fol-lowing steps should be undertaken to ensure trouble-free operation.

a) Sensors ID-numberMake a note of the sensor ID-number and its intended location (sta-tion, position and phase) before installation. The ID-number is located as shown in figure 2.4.1 and unique for each individual sensor. The

Batterycover

Figure 2.3.1Location of

transceiver battery compartment



transceiver and the software utilize this information as the means of identification during the measurement, and it is therefore very impor-tant that the details are correct. After the sensor is installed it may not be practical to view the identification number without first de-energi-zing the surge arrester.

b) Charge the internal power sourcePlace the sensor outdoors, preferably in direct sunlight, for at least 48 hours prior to installation. This will ensure the internal power source is fully charged. For indoor use, refer also to section 2.5 on page 12.

c) Installation of the EXCOUNT-II softwareInstall the EXCOUNT-II software onto your PC. Installation instructions are described in section 2.6 on page 13.

d) Record sensor and station dataRecord each new sensor’s ID-number in the administration part of the PC-program, together with the station data and surge arrester data for where it will be installed, as described in section 2.7 on page 14.

e) Testing the communication between sensor and transceiverPrior to installation, each sensor should be initialised by making a reading of surge counter data only. See section 4 and 5 for details of how to use the transceiver. This will establish a link between the administration details in the PC-program and the sensor. Confirm that contact can be made with the sensor and revert to ABB if any error codes occur. This measurement need not be saved in the PC-program.

Important! The test is best made at a location nearby where the sensors will be installed. During this test, the sensor must be at least 1 m above the ground, not placed on an earthed object or anything with a metal frame, and preferably made with 15 – 30 m distance between the sensor and transceiver. This is most easily achieved by one person holding the sensor at waist height, while another person makes the measurement with the transceiver.

f) Installation on surge arrestersThe preparations are now done and you may proceed with installation of the EXCOUNT-II sensor on the surge arrester. See section 3 on page 18.

Adhesive label(on underside) Engraved

(on topside)

Figure 2.4.1Location of sensor

ID-number



2.5 Installation of battery in the sensorThe sensor’s power sources are the in-built solar panels and the field probe, which obtains the energy respectively from the sun and the electrical field surrounding the surge arrester. The energy is stored in a high efficiency capacitor.

When energy in the sensor falls below a certain level, the sensor swit-ches off the listening function (to conserve energy for recording) until such time that the energy level is sufficient again for communication. This may occur if many attempts to communicate have been made in a row or because there is insufficient sunlight and/or electrical field.

To ensure continuous power a long-life 9V lithium battery may be installed.

Installation of a battery is an absolute necessity for indoor use of the sensor, since no sunlight is available to provide the primary source of power.

NOTE! A long-life battery is pre-installed from the factory for user con-venience to minimize difficulties in communication due to insufficient energy. Regardless, it is highly recommended that the internal high-efficiency capacitor is fully charged before first-time use by following the steps in section 2.4 b.

To replace the battery, open the battery cover using the provided phi-lips screwdriver to loosen the two screws, see figure 2.5.1. Insert the battery, ensuring correct polarity, and then replace the battery cover.

Figure 2.5.1Back view of the sensor with battery cover

Battery



2.6 EXCOUNT-II SoftwareThe enclosed CD includes a version of the EXCOUNT-II software for administration and storage of the data as well as statistical analysis of surge arresters. The program works only on PC´s with operating system Windows 95/98/2000/ME/NT and XP.

To ensure you have the latest version, we suggest downloading the EXCOUNT-II software from the website www.abb.com/arrestersonline.

Included with the delivery is a RS232 cable for communication bet-ween the hand held transceiver and the computer.

2.7.1 InstallationInsert the CD into your computer.Press the START button in lower left cornerSelect SETTINGS then CONTROL PANELDouble-click on the icon ADD/REMOVE PROGRAMSSelect ADD NEW PROGRAMSFollow the instructions on the screen

2.7.2 UninstallationPress the START button in lower left cornerSelect SETTINGS then CONTROL PANELDouble-click on the icon ADD/REMOVE PROGRAMSBrowse to the EXCOUNT-II software and click REMOVEFollow the instructions on the screen.

2.7.3 Using the softwareView the help file for detailed instructions on how to use the sofware.



2.7 First time administration of the sensors1. Record the following details in the PC-program as specified in the

EXCOUNT-II help system for Administration. See figure 2.71 and 2.7.2. • station data • arrester data • EXCOUNT-II sensor data Input this data into the software as described in the help system.Note that each record in the database must have a unique combination of station, position and phase, see figure 2.7.2.

All current generation ABB and earlier ASEA gapless ZnO surge arrester types are included in the arrester data.For other types of gapless surge arresters, simply select the appro-priate IEC class from the dropdown list, see figure 2.7.2.

IMPORTANT! After input of the administration details, an initial reading must always be made to establish a link bet-ween the administration details in the PC software and the sensor on site.

Figure 2.7.1Main menu

Figure 2.7.2Administration data


2. Connect the transceiver to the PC via the data cable. Download the sensor’s ID from the EXCOUNT-II software into the Transceiver as described in the EXCOUNT-II help system for Transfer data, see figure 2.7.3.

IMPORTANT! Check that the date and time on the Transcei-ver are sychronized with the setting on the PC prior to trans-fer, see figure 2.7.4 and 2.7.5. If not set them as described in section 5 of this manual. If this is not done the date stamp from the sensor will be incorrect, which can lead to difficulties in recording measurements.

3. Before going to site, check the Transceiver’s battery status. If necessary, install a new battery.

4. Once at site, individually check that it is possible to make contact with

each sensor as described in section 2.4 e.

Figure 2.7.4Windows date/time

properties menu

Figure 2.7.5Transceiver date/time

properties menu


Figure 2.7.3Main menu



Sensor Installation

Section 3


3. Sensor installation

Safety information

Serious material damage, severe personal injury and/or death can be the result of not following this instruction. Therefore, the personnel responsible for the installation of the equipment shall read and follow this instruction carefully.

Handling and maintenance of all the sensors described in this instruction must be done by personnel trained for this type of work.

WARNING!All work related to the installation of EXCOUNT-II sensors and the surge arresters shall be made with de-energized and earthed conductors. Follow all regulations and rules stated by international or national safety regulations.

Normally, the EXCOUNT-II sensors and the surge arresters operate at a high voltage. Therefore the sensor must be installed in such a way that only qualified personnel has access to it.

3.1 Note the sensor ID numberBefore installation, note the sensor´s ID-number together with the respective arrester station, position, phase and type. The data is used in the EXCOUNT-II software for correct registration. See section 2.7 on page 14.

3.2 Common installation alternativesThe following are two of the most common installation alternatives, and are included here for information only. The separate installation instruc-tion supplied with the actual delivery shall always take precedence.

Alternative 1 (Section 3.4): The sensor is mounted directly on the surge arrester base. This is the best alternative for charging the internal power source and for com-plete measurement.

Alternative 2 (Section 3.5): The sensor is mounted vertically on a planar surface. The sensor is too far away from the surge arrester field, so the only possiblity to charge the internal power source is via the solar cells (or separate DC battery). NOTE! Resistive current measurement is not supported with alternative 2.

3.3 Reference measurementAfter completion of installation of the sensor and energization of the surge arrester, a full set of measurements shall be made for reference and then transfered to the PC software as described in section 5 of this manual. Revert to ABB if any error codes occur during measurement or transfer.


3.4 Installation of sensor alternative 1

Screws, nuts, sockets, washers and conductors are not supplied by ABB unless specified.

Mount EXCOUNT-II (3) on surge arrester´s bottom flange (4) above insula-ting base (5) according to figure 3.3.1. Do not place close to venting duct (if any). Bolt joint (1) and (2) is supplied with ABB insulating base (5).Fittiing and tightening torque according to instructions supplied with insulating base.

EXCOUNT-II is used as earth connection.Connect earth cable with tinplated socket (7) according to figure 3.3.3.Recommended screw: M12 (6)Tightening torque for M12: 84 Nm, use washers


Figure 3.4.1

Figure 3.4.2Top view

Figure 3.4.3Side view


3.5 Installation of sensor alternative 2

NOTE! Resistive current measurement is not supported with this special application.

Mount EXCOUNT-II against planar surface. Use 2 X M6 bolts. Connect upper terminal to flange, bottom terminal to earth via conductor.Recommended screw: M12. Do not mount on earthed plate.

Antenna area, min distance to groundplane: 60 mm

Planar surface

Connect to earth terminal on surge arrester flange

Connect to earth

Min 60 mmto groundplane


Figure 3.5.1Side view

Figure 3.5.2Back view

Figure 3.5.3Front view


Antenna area, min distance to groundplane: 60 mm

Using the transceiver

Section 4


4. Using the transceiver

Important information

EnvironmentTo achieve the best possible lifetime out of your EXCOUNT-II transceiver, avoid exposure to strong sunlight for extended periods, hot temperatures (over +50 º C), cold temperatures (under -10 º C ) and water (the design is showerproof but not watertight).

CleaningTo clean the transceiver use only a damp soft cloth with a mild detergent.

Changing the batteryThe transceiver is powered by a 9 volt battery. Always check the battery status before going to site to take measurements. Replace it when necessary with type 6LR61/PP3.

NOTE! Used batteries should NOT simply be thrown away. Return the battery to a recovery station or leave it with your local ABB representative for environmentally friendly disposal.

4.1 Sychronization of the clocksPrior to transfering data between the PC and the transceiver, check that the date and time are sychronized between both of them. See figure 4.1.1 and 4.1.2. If this is not done, the date stamp from the sensor will be incorrect, which can lead to difficulties in recording measurements.

Figure 4.1.1Windows date/time

properties menu

Figure 4.1.2Transceiver date/time

properties menu



4.2 Range of the communicationThe transceiver can communicate with the sensor within a range of up to 60 meters. However this may differ depending on external factors, including the physical and geographical layout at the site or the pre-sence of radio disturbances in the vicinity. However to obtain the best possible signal strength see section 4.3 to 4.5 below.

4.3 Your body affects the signal strengthKeep the transceiver as far away as possible from your body (arm-length), since your body acts to diminish the energy from the trans-mitter. The antenna is located in the top of the transceiver, so do not place your hands or other obstructions over this area.

4.4 Direction of the transceiver antennaThe signal strength between the antennas in the transceiver and sensor are influenced by their orientation to each other. See figure 4.4.1 for best performance from the transceiver. Note that the best reception and maximum range is obtained by pointing the transceiver at approximately right angles to the sensor instead of directly at it.

Figure 4.4.1Optimal direction of the transceiver antenna

0°

180°

90°270°

Stre

ng

th

Optimal direction Optimal direction



4.5 Direction of the sensor antennaIt may seem logical to be as close as possible to the sensor to obtain the highest signal strength. However this is not the case since the antenna has a signal direction which is nearly horizontal, see figure 4.5.1.To achieve the highest signal strength, you should stand a distance away which is equivalent to twice the height of the sensor above the ground plane. As noted in section 4.4, facing almost 90° degrees to the sensor will also assist in optimizing the signal strength.

Figure 4.5.1Optimal direction of the sensor antenna

Optimal direction

Sensor

Height

2 x Height


Enter

Increase value

Display screen

Decrease valueMove down

Move upGo back

4.6 Transceiver buttons

Figure 4.5.1

Switch the transceiver on/off

To turn on the transceiver press

To turn off the transceiver press

The transceiver turns itself off automatically after 5 minutes.




ABB

>>>>>>>

4.7 Transceiver symbols



4.8 Flowchart, making measurements



Transceiver menus

Section 5


5. Transceiver menus

Stand by

Turn the transceiver on by pressing

Turn the transceiver off by pressing

Got to the main menu by pressing

The transceiver turns itself off automatically after 5 minutes.

The program version is shown in the lower left corner. The E

stands for extended version which includes resistive leakage

current measurement.

5. Main menu

Select alternative with the key.

Then press

Transfer data (see 5.1)

Battery check (see 5.2)

Make measurements (see 5.3)

Set clock and date (see 5.4)

Backlight on

Backlight off (by deafult the backlight is off)

Back to stand-by

5.1 Transfer data


Then press

Data transfer from PC to Transceiver (see 5.1.1)

Data transfer from Transceiver to PC (see 5.1.2)

Back to main menu

ABB2.0.0 E


5.1.1 Data transfer from PC to Transceiver

In this mode, Sensor ID’s can be transfered from the PC to the

transceiver. Connect the data cable to the PC serial port.

PC Serial port Com 1 is selected as default by the software.

See also the software help instructions.

Back to transfer data menu

5.1.2 Data transfer from Transceiver to PC

In this mode data collected from the Sensors can be

transmitted to the PC. Connect the data cable to the PC serial

port. PC Serial port Com 1 is selected as

default.

See also the software help instructions.

Back to transfer data menu

5.2 Battery check

Displays the condition of the battery. Always check the

condition of the battery before transfering data to/from the

transceiver. Change battery if necessary.

If the battery expires during a measurement session,data can

be corrupted or lost.

In such case download the sensor ID’s again and take new

readings.

NOTE! Whenever the battery is replaced the transceiver clock

and date must be reset. (see 5.4)

Back to main menu


0 % 100%


5.3 Make measurements


Then press

Leakage current measurement (see 5.3.1)

Read surge counter data (see 5.3.2)

Resistive leakage current measurement (see 5.3.3)

Full measurement (all of the above)

Back to main meny

5.3.1 Leakage current measurement

Select sensor ID to read data from with the

Start the reading by pressing

A successful transmission is marked with

A failed transmission is marked with

If the transmission was unsuccessful, an error code

will be displayed.

Back to read data menu

5.3.2 Read surge counter data

Select sensor ID to read data from with the key.





will be displayed.



A

A

Progress bar Error code



5.3.3 Resistive leakage current measurement

Not available in all versions.



Before the transmission begins the operating voltage must be

given. (see 5.3.3.1)




will be displayed.


5.3.3.1 Operating voltage


The actual operating voltage must be given when

measuring the resistive leakage current.

The system voltage is displayed as a default value.

Adjust the value to the actual value with

and keys.

Enter the correct value by pressing

NOTE! If the system is 3-phase, the value should be the actual

phase-phase voltage. Otherwise, for 1-phase systems, the value

should be the phase-ground voltage.

The progress bar will indicate that the transmission

has begun.




5.3.4 Total reading




Before the transmission begins, the operating voltage must be

given. (see 5.3.3.1)

Each reading is made in turn automatically.




will be displayed

If any reading is unsuccessfull press

key again to repeat the reading.

Back to total reading menu

5.4 Set clock and date

The cursor highlights which digit to adjust. The cursor is

moved to the next digit by pressing the key.

Each digit is changed by using the and

keys.

After changing any digit the status symbol is changed to X .

When the correct date and clock is set move the cursor to the

X and enter the value by

pressing

This changes the status symbol to



Surge arrester monitoring theory

Section 6


6. Surge arrester monitoring theory

6.1 IntroductionThe rising demands for improved reliability of power supply and reduced maintenance costs have increased the attention on condi-tion monitoring of equipment in HV substations. As far as metal-oxide surge arresters are concerned, there are two important aspects which are related to the reliability of the arresters:

• The stress on the arrester in terms of the intensity and frequency of impulse currents

• The condition of the arrester in terms of its insulating properties in normal service

The first aspect is addressed by performing continuous surge coun-ting and the second by leakage current measurements on regular basis.

The EXCOUNT-II is designed to handle both surge counting and leakage current measurements in a single monitoring system. The EXCOUNT-II system comprises a sensor, permanently mounted at the base of the arrester, a transceiver for wireless communication with the sensor, and proprietary software installed on a personal computer.

In the following, the bases for surge counting and leakage current measurements are described, and the corresponding functions of the EXCOUNT-II are presented. For general information on various diag-nostic methods for metal-oxide arresters, please refer to IEC 60099-5.

6.2 Surge countingGeneralThe primary aim of a surge counter is to give an indication of the stress on the arrester from impulse currents caused by overvoltages. In addition, surge counters may be helpful in analysing the occur-rences of overvoltages on the system, provided the surge counting information is sufficiently detailed.

Surge counting with EXCOUNT-IISurge counters operate at impulse currents above a certain ampli-tude. The EXCOUNT-II sensor is equipped with an impulse current



transformer for registration of discharge currents from 10 A and above, see figure 6.2.1.

The measured current peak values are sorted into five impulse current ranges and stored in the EXCOUNT-II memory along with the date and time of each impulse. The impulse current ranges are: 10 - 99 A, 100 - 999A, 1000 - 4999 A, 5000 - 9999 A and >10000 A. The preci-sion of the impulse current measurements is optimized with regard to lightning current impulses. The EXCOUNT-II memory keeps the information on the 1000 most recent impulses, with a maximum rate of 2 impulses per second. For technical data on surge counting, see technical data in section 8 on page 52.

Figure 6.2.1Internal parts of the EXCOUNT-II sensor

The memory content is transmitted to the EXCOUNT-II transceiver, at the time of the leakage current measurements described below. The surge counter data is later transmitted to a personal computer and analyzed by means of the EXCOUNT-II software.

The use of the detailed surge counting information provided by the EXCOUNT-II is not limited to the estimation of arrester stresses. The information can also be used to analyse the occurrence of the last 1000 lightning overvoltages with regard to date, time and amplitude of the arrester impulse current. When this information is combined with data from event recorders etc., investigations of lightning faults or other system events may be greatly facilitated.

Impulse currenttransformer



6.3 Leakage current measurementsApart from the brief occasions when a surge arrester is functioning as an overvoltage-limiting device, it is expected to behave like an insulator. The insulating properties are essential for the length of life of the arrester and for the operation reliability of the power system. Any deterioration of the insulating properties of a metal-oxide arrester will cause an increase in the resistive leakage current, at given values of voltage and temperature. Therefore, the resistive leakage current in service can be used as a diagnostic tool to check the condition of a surge arrester. Leakage current measurements for diagnostic purposes are usually made on temporary basis at regular intervals. Repeated measurements may be necessary for closer investigations, if significant changes in the condition of an arrester are revealed by temporary measurements.

Leakage current of metal-oxide arrestersThe total leakage current of a metal-oxide arrester can be divided into capacitive and resistive parts, see figure 6.3.1, with a predominant capacitive component and a significantly smaller resistive part (5 to 20% of the total current). The capacitive leakage current is caused by the permittivity of the metal-oxide varistors, by the stray capacitances and by internal grading capacitors (if applied).

A large increase in the resistive leakage current is needed before a noticeable change occurs in the total leakage current level. Therefore, the total leakage current is unsuitable for arrester diagnostic purposes. Instead, it may be used for other diagnostic or maintenance purposes, e.g. to estimate the prevailing amount of insulator surface pollution and the associated need for insulator washing, greasing etc. of the insulators in the substation.

The resistive component of the leakage current, on the other hand, is a sensitive indicator of any changes in the voltage-current cha-racteristic of a metal-oxide arrester. The EXCOUNT-II is equipped for measurement of the total leakage current and, optionally, for measure-ment of the resistive leakage current. In this way, the EXCOUNT-II may be equipped to fulfil different diagnostic needs in addition to surge counting.



Figure 6.3.1Electrical representation of metal-oxide surge

arrester in the leakage current region

Resistive leakage currentThe resistive leakage current is defined as the peak value of the resis-tive component of the leakage current, i.e. the instantaneous value of the leakage current when the voltage across the arrester is at its maxi-mum (dU/dt = 0). In the leakage current region, the resistive current depends on the voltage stress and temperature of the varistors. The typical non-linear behavior of the resistive leakage current is shown in figure 6.3.2 for two different varistor temperatures. The voltage stress is expressed as the ratio of the operating voltage to the rated voltage of the arrester (U/Ur).

Figure 6.3.2Example of voltage-current characteristics

of a metal-oxide surge arrester


The maximum continuous operating voltage of an arrester (the Uc according to IEC, or the MCOV according to ANSI) usually cor-responds to a voltage stress in the range 0,7-0,85 p.u. of the rated voltage.

In normal arrester applications, the operating voltage stress usually ranges from 0,5 to 0,8 p.u. of the rated voltage. In this range, the resistive leakage currents at +20°C may vary from 10 to 600 µA depending on the size and make of the varistors.

Harmonics in the total leakage currentThe non-linear voltage-current characteristic of a metal-oxide arrester, illustrated in figure 6.3.2, gives rise to harmonics in the total leakage current when the arrester is energized with a sinusoidal voltage. The harmonic content depends on the degree of non-linearity, which is a function of voltage stress, temperature and make of the arrester. As an example, the third harmonic content of the total leakage current is typically 10-40% of the resistive current.

The harmonic content of the total leakage current can, therefore, be used as an indicator of the resistive leakage current. Using harmonics for measuring the resistive leakage current is advantageous compared to other methods, since no voltage reference is needed to determine the resistive part of the total leakage current. The third order harmonic is of special interest in this respect, since it has the largest magnitude of the current harmonics.

The actual resistive leakage current level can be readily determined from measurements of the third harmonic, provided the appropriate information is available regarding the third harmonic content of the resistive current at the prevailing voltage stress and temperature. This information is specific to the arrester make and type, and must there-fore be supplied by the arrester manufacturer.




Another source of harmonics in the total leakage current is the har-monic content in the system voltage. The voltage harmonics produce capacitive harmonic currents in the arrester. This is clearly illustrated in figure 6.3.3, showing results from total leakage current measurements on two different arresters in service conditions that are significantly different in terms of system voltage harmonics.

Figure 6.3.3Total leakage currents of metal-oxide

surge arresters in different service conditions

The capacitive harmonic currents produced by the voltage harmonics may be of the same order of magnitude as the harmonic currents generated by the non-linear resistive leakage current. This means that the third harmonic content originating from the system voltage interferes with the third harmonic content associated with the resistive leakage current of the arrester. In order to perform accurate measure-ments of the resistive leakage current by means of third order harmo-nic analysis, it is therefore necessary to compensate for the third order harmonic content in the system voltage.


Leakage current measurements with EXCOUNT-IIWhen the EXCOUNT-II is optionally equipped for measurement of resistive leakage currents, the measurement is based on third har-monic analysis of the total leakage current with compensation for the third harmonic in the system voltage. The compensation is performed by simultaneous measurements of both the total leakage current of the arrester and the current induced in a field probe, the latter being proportional to the harmonic content in the system voltage.

The principle for measurement of the resistive leakage current with the EXCOUNT-II is the same as for the original leakage current monitor, LCM, developed by ABB Switchgear and TransiNor, and described in detail in [2].

The procedure for total leakage current and field probe current measurements with EXCOUNT-II is presented step-by-step in the fol-lowing:

Figure 6.3.4Internal parts of the EXCOUNT-II sensor


Zero-flux currenttransformer Field probe



The total leakage current is measured by means of the zero-flux current transformer, and the electric field generated by the system voltage is measured in terms of the current induced in the field probe, both shown in figure 6.3.4. The field probe current, see figure 6.3.5, is used to compensate for the harmonic content in the system voltage.

Every 10 seconds, the data communication system of the EXCOUNT-II sensor is activated to establish contact with an EXCOUNT-II transceiver in the vicinity. If successful, the sensor makes the total leakage current and field probe current measurements described above and transmits the measured data to the transceiver. In addition, the sensor also trans-mits surge counting data along with data on ambient temperature and sensor identity, etc. For details on the sensor/transceiver data commu-nication system, see technical data in section 11 on page 42.

Figure 6.3.5Principle of field probe for determination

of system voltage harmonics

In the transceiver, the magnitudes of the total leakage currents are checked with regard to the measurement ranges (see Table 1). Extre-mely low current levels, caused by the arrester being out of opera-tion etc., are also identified. Accepted measurements are analysed by means of Discrete Fourier Transformation (DFT) to determine the magnitude and phase angle of the first and third order harmonic components of the total leakage and field probe currents (for resistive leakage current option). Several measurements are analysed to verify the stability of the current levels. The total leakage current and field probe current data (as well as the surge counting data) are temporarily stored in the transceiver for later downloading to a personal computer.

Field probe

Electric fieldsurrounding the arrester

Ip


By means of the EXCOUNT-II software, the total leakage, field probe current and surge counting data are analyzed and presented for each arrester. The resistive leakage current level (optional) is calculated in two steps: First, the resistive third harmonic of the arrester resistive leakage current, with compensation for the third harmonic in the voltage, is determined by the equation below (for a three-phase instal-lation). For a detailed explanation of the equation, see [2]. Secondly, the resistive leakage current is determined from the resistive third harmonic current by means of information supplied by the arrester manufacturer.

The ratio of the total resistive leakage current to the third harmonic current depends on the operating voltage stress (the operating voltage divided by the rated voltage) and the arrester temperature (in practice, the ambient temperature). These parameters are therefore recorded at the time of the total leakage current and field probe current measu-rements. The ambient temperature is automatically measured by the sensor, while the operating voltage is entered into the transceiver at the time of the total leakage current and field probe measurement.

Figure 6.3.6

Resistive leakage current information from the surge arrester manufacturerThe information from the arrester manufacturer is given in accordance with IEC 60099-5 [1] for each arrester type. All ABB type arresters are included in the EXCOUNT-II software to allow measurements of resis-tive leakage currents. To be ably to correctly calculate the resistive lea-kage current for non-ABB type of arresters the characteristics of that type must be added to the data base. Please contact your ABB office for further information. The manufacturer’s information comprises:

• Maximum recommended levels of total resistive leakage current and resistive third harmonic current at a specified voltage stress (U/Ur = 0,7) and a specified ambient temperature (+20°C). These conditions are referred to as “standard operating conditions”.




• Multipliers for the total resistive leakage current and the resistive third harmonic as functions of voltage stress and ambient tempera-ture. These multipliers are used for converting the actual values of voltage stress and ambient temperature at the time of measurement to standard operating conditions. Examples of such multipliers are given in Figures 6.3.7 and 6.3.8.

Figure 6.3.7Typical information for conversion to

standard operating voltage conditions

Figure 6.3.8Typical information for conversion to

standard ambient temperature conditions


Evaluation of resistive leakage current levelsBy means of the manufacturer information, the resistive leakage current level is determined from the resistive third harmonic current, and the results obtained under the actual operating conditions are converted to the standard operating conditions. After conversion, the results of the leakage current measurements can be evaluated in two different ways:

• The converted leakage current level can be compared with previous results obtained for the same arrester, to reveal any significant chan-ges in the leakage current level over time.

• The converted leakage current level can be compared with the maximum level recommended by the arrester manufacturer.

These comparisons are carried out by the EXCOUNT-II software. The results may be presented and documented in graphs, tables and reports.



Radio transmission protocol

Section 7


7. Radio transmission protocol

7.1 Packet communication protocolAll radio channels are subject to noise, intereference and fading. In many cases, radio channels are shared by several users of services. Packet communication protocols are widely used to achieve error-free communi-cations over imperfect and/or shared communication channels.

Almost all short-range wireless data communications use some form of packet protocol to automatically assure information is received correctly at the correct destination. A packet generally includes a training pream-ble, a start symbol, routing information (to/from, etc.) a packet ID, all or part of a message and error detection bits. Other information may be included depending on the protocol.

Figure 7.1.1 shows one of the packet formats used in EXCOUNT-II. The structure begins with a training preamble, which improves weak signal detection at the receiver by ”training” the data slicer for best noise immu-nity, and providing signal transitions to train the clock recovery process. The training preamble usually consists of several bytes of a 1-0-1-0-1-0 ... sequence.

EXCOUNT-II RF Link Packet Format

PreambleStart

SymbolTo Byte

From Byte

Packet Number

Size/Status Byte*

MessageFCS High

ByteFCS Low

Byte

Figure 7.1.1

The preamble is followed by a start symbol (often called a start vector), which is a distinct pattern of bits marking the start of the information sec-tion of the packet.

The start symbol is followed by ”to” and ”from” address information. In the EXCOUNT-II protocol, the packet ID is followed by message size or status information.


7. Radio transmission protocoll

The message then follows . The following two bytes of the packet com-prise a 16 bit error checking code (frame check sequence), based on the X.25 packet standard (ISO 3309). The error checking code is recompu-ted at the destination to confirm error-free detection. The ISO 3309 frame check sequence provides very high confidence of error detection for packets up to 256 bytes in length.

In summary, EXCOUNT-II protocols provides the following features:

• 16-bit ISO 3309 error detection calculation to test message integrity

• Automatic packet retransmission until acknowledgement is received; 8 retries with semi-random back off plus ”acknowledge” and ”link failure” alarm messages.



9. Disposal

Technical data

Section 8


GeneralSensor Transceiver

Climatic conditions Sealed, water-tight design, IP67(Battery compartment, IP 65) Weather-proof, IP 54

Ambient temperature range

–50 °C to +60 °C Operation: –40 °C to +60 °C -10 °C to +50 °C

Measuring frequencyrange 50 or 60 Hz (automatic) N/A

Short-circuit capability 65 kA acc. to IEC 60099-4 N/A

Primary power supply

Outdoor version: Built-in solar cell and field probeIndoor use: 9 Volt lithium battery U9VL

9 Volt battery Alkaline type 6LR61/PP3

Battery replacement period 8 years with 1200 mAh lithium battery > 4 hours

Weight (without battery) 2072 g 221 g

8. Technical data

8.1 Technical data OptionalMeasuring range of resistive leakage cur-rent (peak level)

10 – 2000 µA

Error in resistive leakage current

< 10 µA (10 – 50 µA); < 20% (50 – 2000 µA

Sensor/Transceiver Data Communication

TypeAM radio (OOK)ETSI and FCC approved

Frequency

868.35 MHz (916.50 MHz for North America and Australia)

Antenna Integrated on circuit-board

Output power -3dBm (0.75 mW)

Operation range (max.)Environment dependent

60 m

Surge countingCounting threshold (8/20 µs) 10 A

Surge current amp-litude classification (8/20 µs)

10–99 A100-999 A 1000-4999 A5000-9999 A > 10 000 A

Error in surge coun-ting amplitude < 20%

Surge counting time resolution < 0.5 s

Surge counting time stamp format

YYYY:MM:DD:hhmmss(1 s resolution)

Surge counting memory capacity

1000 registrations (wrap-around)

Leakage Current MeasurementMeasuring range of total leakage 0.1 – 50 mA current (peak level)

0.1 – 50 mA (10-bit A/D conver-sion, autorange)

Error in total leakage current < 5%


8. Technical data

EXCOUNT-IIID. No: XXXXXXXXCat. No:1HSA44XXXX-XMade in Sweden

Figure 8.2.1Sensor

Figure 8.2.2Sensor

8.2 Dimensions



Disposal

Section 9


9. Disposal

DisposalWhen the EXCOUNT-II sensor and/or transceiver is taken out of ser-vice its components shall be disposed of according to local regula-tions. The sensor is assembled in a sealed case, making it difficult to dis-mantle completely for separate disposal.

Both items contain electronic, metal, rubber and plastic components. The 9V battery in each device must be removed and disposed of separately.


Transceiver error codes

Section 10


10. Transceiver error codes

Error code Description Suggested cause and action

01 System error Turn off the transceiver and re-start. If the error persists, a serious internal fault has occurred with the transceiver. Contact your EXCOUNT-II service representative.

11 Prohibited action The user has attempted to do something which is prohibited. For example, it is not permitted to re-transmit an already successful transmission. Turn off the transceiver and re-start.

21 Checksum error An error occurred in the data transmission and the data has been lost or corrupted. Interference from a nearby cellular/mobile phone can be a likely cause. Wait 30 seconds before attempting to re-transmit the data.

31 EEPROM data read error The transceiver could not read from the internal EEPROM memory. Turn off the transceiver and re-start. If the error persists, contact your EXCOUNT-II service representative.

32 EEPROM data write error The transceiver could not write to the internal EEPROM memory. Turn off the transceiver and re-start. If the error persists, contact your EXCOUNT-II service representative.

41 Low temperature The ambient temperature is lower than defined in the database for resistive current measurements. (Lowest defined temperature is -10 º C). Take new measurements at another time.

42 High temperature The ambient temperature is higher than defined in the database for resistive current measurements. (Highest defined temperature is +60 º C). Take new measurements at another time.

51 Too low field probe current The system voltage is too low to generate suf-ficient current in the field probe in the sensor. Check that the sensor is correctly mounted (see chapter sensor installation, section 3 and assem-bly instruction included with the sensor).

52 Too high field probe current The system voltage is too high. Check that the sensor is correctly mounted (see chapter sensor installation, section 3 and assembly instruction included with the sensor).




61 Low leakage current The measured leakage current is too low. Check that:a) the line is correctly energized.b) the sensor is correctly mounted. See chapter

sensor installation, section 3 and assembly instruc-tion included with the sensor.

If none of the above are found to be the cause take new measurements at another time.

62 High leakage current The measured leakage current is too high. Check that:a) the line is correctly energized.b) the sensor is correctly mounted. See chapter

sensor installation, section 3 and assembly instruc-tion included with the sensor.

If none of the above are found to be the cause take new measurements at another time.If the error persists the surge arrester may be sus-pect.

70 Unstable leakage current

A stable value for the leakage current cannot be measured. A likely cause may be an unstable line voltage. Take new measurements at another time.

80 Sensor not found

Read the safety information in section 3 carefully before working with the sensor.

The sensor ID was not recognised by any locally pre-sent sensor. Wait 30 seconds before retransmitting again. If contact still cannot be established, check:a) the chosen sensor ID is present at this stationb) the distance and orientation to the sensor is as

described in section 4.c) interference from a radio frequency sourced) battery status to ensure the voltage in the

transceiver battery is not too low.Note! If none of the above are found to be the cause, then consider the following:When the energy in the sensor falls below a certain level, the sensor switches off the listening function (to conserve energy for recording) until such time that the energy level is sufficient again for communication. This may occur if many attempts to communicate have been made in a row or because there is insufficient sunlight and/or electrical field. Should unexplained difficulties occur during communica-tion, it is suggested to wait until another time to make measurements or else install a 9V battery in the sensor.



81 Transmission buffer error Turn off the transceiver and re-start. If the error persists, a serious internal fault has occurred with the Transceiver. Contact your EXCOUNT-II service representative.

82 Connection lost

Read the safety information in section 3 carefully before working with the sensor.

The sensor recognised its ID but the connection was lost during the transmission. Wait 30 seconds before re-transmiting again. If the error persists, check:a) the distance and orientation to the sensor is as

described in section 4.b) interference from a radio frequency sourcec) battery status to ensure the voltage in the

transceiver battery is not too low.

Note! If none of the above are found to be the cause, then consider the following:When the energy in the sensor falls below a certain level, the sensor switches off the listening function (to conserve energy for recording) until such time that the energy level is sufficient again for commu-nication. This may occur if many attempts to com-municate have been made in a row or because there is insufficient sunlight and/or electrical field. Should unexplained difficulties occur during com-munication, it is suggested to wait until another time to make measurements or else install a 9V battery in the sensor.



12. Index

Index

Section 11


11. Index

A

Administration 14arrester data 14sensor data 14station data 14transceiver date/time 15windows date/time 15

Antenna 23, 24

B

Battery 12, 56battery check 31

C

Cleaning 22

D

Data cable 7, 10, 15, 31Data transfer 31Dimensions 53Disposal 56

E

Earth cable 19Earth connection 19

F

Field probe 43

I

ID number 11Installation of battery 12Insulating base 7

Internal power source 11

K

Key to the symbols 3

L

Leakage current measurement 32, 38

M

Making measurements 27Measuring principle 7

P

Packet communication protocol 48PC 7, 13Pre-installation 10

R

Radio transmission protocol 47packet communication protocol 48

Range of the communication 23Reference measurement 18Resistive leakage current 33, 39RS232 7, 10, 15, 31

S

Safety instructions 3Sensor 7, 17

antenna 24field probe 43signal strength 24ID-number 11, 18

Sensor Installation 17common installation alternatives 18


11. Index

earth cable 19earth connection 19reference measurement 18

Set clock and date 34Signal strength 23Software 13Surge arrester monitoring 35

leakage current measurements 38resistive leakage current 39surge counting 36theory 35

Surge counter data 32Surge counting 36Sychronization of the clocks 22

T

Technical data 51, 52Total reading 34Transceiver 21

antenna 23buttons 25cleaning 22date/time 22error codes 57range of the communication 23signal strength 23sychronization of the clocks 22transceiver buttons 25transceiver menus 29transceiver symbols 26

Transceiver menus 29battery check 31data transfer 31leakage current measurement 32main menu 30

make measurements 32operating voltage 33resistive leakage current 33set clock and date 34stand by 30surge counter data 32total reading 34transfer data 30

Transceiver symbols 26


1HS

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ABB Power Technologies ABHigh Voltage Products Surge ArrestersSE-771 80 LUDVIKA, SwedenTel. +46 (0)240 78 20 00Fax. +46 (0)240 179 83E-mail: [email protected]: http://www.abb.com/arrestersonline

Documents

1HSA 801 080-15en EXCOUNT-II Users guide EFTER KORR med … · 2. Before installation 2.5 Installation of battery in the sensor The sensor’s power sources are the in-built solar