Type TEC, Transformer Electronic Control System

Type TEC, Transformer Electronic Control System Technical, installation, operating, maintenance and service manual for TEC cabinet and sensors 1ZSC 954003-006 en, Rev. 3, 2005-11-30

Contents 1 Technical manual 5 1.1 Scope 5 1.2 System architecture 5 1.3 TEC functionality 6 1.4 Hardware 10 1.4.1 Cabinet 10 1.4.2 Electronic boards and terminals 16 1.4.2.1 Power supply 16 1.4.2.2 Processor 18 1.4.2.3 Analogue input 4-20 ma 19 1.4.2.4 Temperature input Pt 100 20 1.4.2.5 Digital input 21 1.4.2.6 Control and output 24 1.4.2.7 Motor relay TC180 25 1.4.2.8 Alarm box 26 1.4.2.9 Display 27 1.5 Performed tests 28 1.5.1 EMC (Electro Magnetic Compability) tests 28 1.5.2 Mechanical tests, vibration and seismic 29 1.5.3 Climate tests 29 1.6 Trip, alarm and warning output from TEC 30 1.6.1 Output signals from TEC cabinet 30 1.6.2 Alarm/Warning output options 30 1.6.3 Trip output options 30 1.6.4 Connection of devices in parallel both traditionally and to TEC 32 1.7 Ordering data 34 1.7.1 Load test 34 2 Installation manual 35 2.1 Connection table 35 2.2 Sensors 36 2.2.1 Air temperature 36 2.2.2 Oil temperature 37 2.2.2.1 Use of TEC bottom oil sensor 37 2.2.3 Current transducer 38 2.2.4 Hydrogen gas in oil 38 2.2.5 Moisture in oil sensor 38 2.3 Cables and earthing 39 2.3.1 Pt 100 39 2.3.2 4-20 ma and Digital In 39 2.3.3 RS 485 39 2.3.4 Fibre optic 39 2.3.5 Cable entry and Roxtec 40 2.4 PC 40

3 Operating manual 41 3.1 Start sequence 41 3.2 Display on cabinet 41 3.2.1 Status light 42 3.3 Warning, Alarm and Trip signal 42 3.4 TEC during transformer test 42 3.5 Sensor failure 42 3.5.1 Sensor failures influence on functions 43 3.5.2 Other back-ups in case of failures 44 4 Maintenance and service manual 45 4.1 Loading of new program in TEC 45 4.1.1 Hardware needed and connections 45 4.2 Trouble-shooting 46 4.3 Replacement of board 47 4.4 Spare part list 47 5 Contact list 47 4 1ZSC 954003-006 en, Rev. 2

1 Technical manual 1.1 Scope This manual describes all aspects of the Control IT Transformer Electronic Control (TEC), version 1.02. The information is grouped into two manuals: one covering TEC cabinet with sensors, and one covering the interface. This means that information on a specific item, such as a temperature sensor, is given in several places. Information that is needed at a specific occasion is in some cases gathered in a separate section, but it is recommended that all users have a general knowledge of TEC functions and read through both manuals. 1.2 System architecture Transformer Cabinet and Sensors TEC CABINET ON CABINET Di splay ALARM WARNING NORMAL Standard 3 dry contacts for: Trip Alarm Warning TEC CABINET TEC CABINET ON CABINET TEC Display CABINET ALARM ON CABINET WARNING TEC Display CABINET ALARM ON CABINET NORMAL WARNING Display ALARM ON CABINET NORMAL WARNING Display ALARM NORMAL WARNING NORMAL Fibre Optic Bus Option Relay box with 6 dry contacts to distinguish between Alarms TEC PC in station Electric Bus TCP/IP Remote PC with Internet Explorer Connections LAN (standard) Modem (special option) SCADA Data from all sensors on a transformer are collected by TEC. The sensors are grouped in four types: Temperature sensors for oil and ambient air (Pt 100) Analogue sensors to measure quantities such as load current or amount of hydrogen gas in oil (4-20 ma) Digital sensors indicating an on-off status, e.g. contacts of a sudden pressure relay Position sensor (resistor bridge) for tap-changer position. The sensor information is brought into the processor via input cards, one card for each of the three sensor types. The processor contains a detailed mathematical model of the transformer including measured data at the heat run test. Taking actual oil temperature and load conditions into account, TEC calculates the hot-spot temperature. As a result of the temperature calculations, TEC starts and stops the coolers and even prepares for rapid load increases. This is done with a separate board with small relays. This board is placed in connection with the cooler contactors in the transformer control cabinet and communicates with the TEC processor via a data bus in order to simplify the wiring. TEC can be connected to a traditional control system and operate contacts in those circuits, e.g. to give a trip signal. 1ZSC 954003-006 en, Rev. 2 5

A status light on front of the TEC cabinet indicates the status of the transformer and the most important measured and calculated values are also displayed there. However, the major user interface is via a PC, normally located in the station control room. The monitoring and control functions run continuously in the processor independently of the connection to the PC user interface. The PC stores all historical data about the transformer and it is possible to analyse the transformer condition in detail, e.g. accumulated ageing of the insulation and time to next service of the tap-changer. The PC also contains simulation programs for overload and other emergency situations. Remote access to TEC and connection of TEC to a superior control system will be possible in the future, as the PC has an OPC server. 1.3 TEC functionality The following functionality is available in TEC version 1: Hot-spot calculation Winding hot-spot will be calculated to fulfil both IEC and IEEE. Calculations can be made for 3 windings simultaneously: high voltage, low voltage and tertiary windings. The calculations are made according to: ON (Oil Natural) cooled transformers Θ h = Θ o + Hg r K y OF (Oil Forced) and OD (Oil Directed) cooled transformers Θ h = Θ b + 2[ Θ imr - Θ br ]K y + Hg r K y It should be noted that under certain load conditions the top oil temperature can be higher then the hot-spot temperature. Correction on OD-cooled transformers Θ h = Θ h + 0.15(Θ h - Θ hr ) For an OD-cooled transformer a correction has been applied to the result of the OFequation in case of Θ h - Θ hr >0 In IEC the criteria is K>1. (In case of loads exceeding 100 % rated current) The intention of this must however been to correct when the actual hot-spot temperature exceeds the one measured during test. Θ o = Top oil temperature Hg r = Hot-spot to top-oil gradient K = Load factor (load current/rated current) y = Winding exponent Θ imr = Average oil rise (rated conditions) Θ br = Bottom oil rise (rated conditions) Θ b = Bottom oil temperature = Rated hot-spot temperature Θ hr The hot-spot values are shown on the TEC cabinet display. If an interface exists, the values will be stored and shown there. (See the manual for the interface.) 6 1ZSC 954003-006 en, Rev. 2

Transformer top and bottom oil temperature The top and bottom oil temperature will be shown on the TEC cabinet display. If an interface exists, the values will be stored and shown there. (See the manual for the interface.) Cooling Control The cooling will be controlled from - Top oil temperature - Hot-spot temperature - Forecast on the hot-spot made from actual load and ambient temperature. The cooling control aims to keep the transformer at a fairly constant temperature. Up to 6 independent cooling groups can be controlled. A logic control that all cooler groups are evenly used. All cooler groups are started at least each week. There is a delay (10 seconds) between start of cooler groups to avoid that all start at the same time that can create a pressure pulse in the transformer or a peak consumption of power. If TEC of some reason stops to work or the connection between TEC and the motor relay is broken all cooling will start. A traditional top oil thermometer will start all cooler groups if the TEC system for some other reason does not work. Service prediction cooling equipment The time each cooling group has been in operation is measured and displayed in the station interface. It can be used to predict when service is needed. A log is also available to see events related to the cooling equipment. Ageing The ageing from the warmest winding hot-spot is calculated during service according to IEC if normal craft paper is used in the winding or according to IEEE if thermally upgraded paper is used. The actual ageing speed is displayed in %. The accumulated ageing is also calculated and displayed in years. The calculations are made in the TEC processor and the accumulated ageing is also stored there. (See the manual for the interface.) The accumulated ageing and the ageing speed are displayed in the interface. (See the manual for the interface.) 1ZSC 954003-006 en, Rev. 2 7

tec_0086 Ageing graph Example: Winding hot-spot temperature 98 C F IEC = 1 Ageing speed 100 % If the hot-spot temperature increases 18 C to 116 C F IEC = 8 Ageing speed 800 %. The ageing speed is eight times faster compared to the one at 98 C. If the hot-spot temperature decreases 18 C to 80 C F IEC = 0.125 Ageing speed 12.5 %. The ageing speed is 12.5 % of the one at 98 C. Hydrogen equivalent detection This function will received a signal from a hydrogen detector which is a gas-in-oil detector that is sensitive to H 2, CO, C 2 H 2 and C 2 H 4. The resulting value is an H 2 - equivalent ranging from 0 2000 ppm. The result will be shown in the display. Electrical data will be stored in the interface. (See the manual for the interface.) Tap-changer contact wear The contact wear function will keep track on how many operations has been done on each contact, and calculate the wear. The wear on the contacts are stored in the TEC processor. From that information it will calculate the number of operations and time to next service/ contact exchange. As those events are approached there will be warnings, and if actions not are taken in due time for the contact exchange there will be alarms. This function provides prediction and a reminder when overhaul and contact exchange are needed. The results are shown in the interface. (See the manual for the interface.) The warning and alarm signal will also appear on the cabinet status lights. Transformer temperature balance (optional) The transformer temperature balance function will keep track on the temperature in the transformer and compare with the theoretically calculated temperature. The default setting is that, if the average transformer temperature becomes more than 15 ºC higher than expected for 24 h, there will be an alarm. The function can indicate a cooling problem at lower load conditions before the problem gives a warning due to high top oil temperature. The calculated temperatures shall be used as references to the actual temperatures over a longer time. Note that the temperature balance does not support all types of cooler configurations. (See ordering data help.) 8 1ZSC 954003-006 en, Rev. 2

Tap-changer temperature balance (optional) This function calculates if there is excessive heat generation in the tap-changer. At normal conditions there is a known balance between the theoretical calculated losses in the tap-changer and the heat transferred from the tap-changer to its surroundings. The default setting is that, if the average temperature in the tap-changer is more then 15 ºC above the calculated value for 24 h there will be an alarm. Moisture in transformer oil detection This function will receive a signal from a moisture sensor. The value in ppm will be shown in the TEC display and in the PC interface. It is possible to set a warning and alarm level for the moisture content in the order data sheet. Overload capacity (optional) A prediction of the maximum allowed load under the existing ambient conditions is displayed in the main interface. At this loading the top oil and hot-spot temperature should not exceed preset values in the order data sheet. Voltage measurement The voltage on the high voltage side can be displayed. The values will be shown in TEC Monitor. Historical values can also be displayed in TEC Monitor. Tap-changer temperature The temperature in the tap-changer is measured and stored. This temperature can easily be compared to the transformer and outdoor temperature, to see that the situation is stable. In the same graph the load can be displayed. Some rules are also described in the chapter about operations. The temperature in the tap-changer(s) is measured and shown on the TEC display. Tap-changer position This function displays the tap-changer position on the cabinet display as a number. In the station interface it is optionally possible to convert into another format. (See the manual for the interface.) Cabinet conditions This function reads the temperature and the relative humidity on the processor board in the cabinet. The readings will be available both as a conditions at the present time, but also as a histogram showing the frequency of the different temperatures and humidities. Load forecasts In the station interface it is possible to do load forcasting on hot-spot and top oil temperatures. (See the interface manual.) Event log (See the interface manual.) Documentation (See the interface manual.) Provided on a CD. Tap-changer service videos (See the interface manual.) 1ZSC 954003-006 en, Rev. 2 9

1.4 Hardware 1.4.1 Cabinet tec_0097 Power supply Universal 110-230 VAC, 50/60 Hz, and 85-265 VDC. It is recommended to connect both AC as main supply and DC from station battery as spare supply. It is also possible to connect 2 different AC supplies. TEC will automatically switch without interruption in case of outage on any of them. Front panel Push button to control the LCD display Rolling LCD display showing top-oil temperature, up to three hot-spot temperatures, bottom oil temperature, load, tap-changer position, tap-changer temperature and hydrogen content (if applicable). Temperatures are displayed in both Celsius and Fahrenheit Status light with three lamps (green/yellow/red) 10 1ZSC 954003-006 en, Rev. 2

Environmental Operation temperature... -40 to +55 C (-40 to 122 F) Degree of protection... IP 54, according to IEC 60529 Temperature cycling tested... -40 to +70 C, 90% humidity according to IEC 60068-1, -2,-3 and -5 Dimensions (mm)... Width 500, Height 600, Depth 300 Weight... 35 kg EMC compliance... IEC 61000-4 or higher Vibration tested... IEC 60255-21-1,-2, -3 and IEC 60068-2-6, -27, -29 Temperature cycling... IEC 60068-2 Max cable area to terminals... 2.5 mm² Max cable area to temperature input Pt 100... 1.5 mm² Input parameters 8 insulated analogue 4-20 ma via terminals, for current transformers, sensors etc. 4 insulated Pt100 direct inputs, for temperature sensors 12 insulated digital input via terminals, for fan motor status, alarm / trip signals etc. Input tap-changer position transmitter R tot 80 W Amount of input signals can be increased Output parameters 3 outputs for alarm, warning and trip signals 6 outputs to start cooler groups (fans) Permitted load breaking capacity on output terminals AC 250 V 8 A, DC 125 V 0.1 A L/R=7ms, DC 30 V 5 A Fibre optic cable The connection between TEC and the station computer is made via optic cable. 1ZSC 954003-006 en, Rev. 2 11

Extra roof Status lights Display Lamps Space for extra boards Electronic boards 24 V power supply Standard terminals Heater Space for extra terminals tec_0045 Cable entry Status light Red indicates Alarm or Trip Yellow indicated Warning Green indicates Normal 12 1ZSC 954003-006 en, Rev. 2

Display on cabinet tec_0063, tec_0073 Displayed information A TOP OIL B1HOT-SPOT HV B2HOT-SPOT LV C BOTTOM OIL D LOAD E OLTC POSITION F OLTC TEMP1 G HYDROGEN H2 MOISTURE TRAFO MOISTURE OLTC Heater The heater in the cabinet is connected to TEC s AC supply. It is designed for an AC supply of 100-240 V. Depending on the temperature in the cabinet it can give a heating power between 100-135 W. (At -30 C the heating power is 135 W.) Lamp The 2 lamps in the cabinet are standard lamps for lorries 24V, 10W. 24V power supply The 24 V power supply is only intended to supply the lamps. 1ZSC 954003-006 en, Rev. 2 13

Standard terminals tec_0046 Power supply Data communication Analogue input Digital input Control and output Cable between TEC and transformer cabinet The cable is supplied to make an easy connection between the transformer cabinet and TEC. It is up to the transformer manufacturer to use the the provided cabling as they see fit. The shielded cable A is intended to use for the RS 485 connection to the motor board. There are 2 more shielded cables and 24 single conductors in the cable. Connection to transformer control cabinet. Hole PG29 (D = 38 mm) tec_0047 Connection to TEC cabinet 14 1ZSC 954003-006 en, Rev. 2

For cable Ø 9.5-32.5 mm (5x) Cable sealing (option) For cable Ø 3-16.5 mm (14x) Connection to transformer control cabinet Optic fibre 342 159 176 66 256 178 40 278 Ø 9 1) Standard cable entrance plate Earthing terminal M12 510 96 78 A 500 300 526 340 600 M10 37 648 601 A tec_00207 1) Mounting holes on the transformer. 25 1ZSC 954003-006 en, Rev. 2 15

1.4.2 Electronic boards and terminals The electronic boards are mounted on a back-plane providing internal communication and power supply between the boards. Connection to external power and signal sources is normally done via the terminals at the bottom of the cabinet. A sign with the connection table is placed on the inside of the TEC cabinet door. The boards are placed in the following order from left to right: Power supply board, TC 110 Processor board, TC 121 Analogue input 4-20 ma board, TC 130 Temperature input Pt 100 board, TC 140 Digital input board, TC 150 Control and output board, TC 160 To the right of these standard boards, there are three extra slots for temperature input Pt 100 boards and/or digital input boards. The standard set-up also comprises: Motor relay board, TC 180, in the transformer control cabinet Alarm box 1, TC 181 Alarm box 2, TC 182 Display board, TC 170, at the front of the TEC cabinet. 1.4.2.1 Power supply TEC can work with either AC or DC power supply. It is recommended to connect both AC as main supply and DC from the station battery as back-up. It is also possible to connect 2 different AC supplies. The power supply board will automatically switch between the two supplies without interruption if one fails. The power consumption of the electronic boards is <20 W plus the consumption of sensors. The cabinet heater element is connected to the input AC supply and it has a current peak of approximately 8 A for some seconds each time it starts. It is recommended to have at least a 10 A fuse. The terminals can be disconnected by moving the orange part downwards. 85-264 V AC (or DC) input via terminal group X1 85-264 V DC (or AC) input via terminal group X2 24 V DC output via terminal group X3 to TEC display and current transducers tec_0048 tec_0049 16 1ZSC 954003-006 en, Rev. 2

Terminal group X1 1 Input 85-264 V AC 50/60 Hz line voltage. 2,3 Output AC line voltage. Connected to X1:1 and is always energized, even if the terminal disconnection bar is moved to the disconnected position. Can be used to supply special sensors with power. 4 Input AC neutral. 5, 6 Output AC neutral. Terminal group X2 1 Input 85-264 V DC positive. 2 Input 85-264 V DC negative. Dangerous voltage! WARNING Terminal group X3 1 Output 24 V DC positive from the power supply board. The display (1.6 W) is internally wired to this supply. Up to 3 current transducers can also be connected here. Maximum total load on this supply is 5 W. 2 Output 24 V DC negative from the power supply board. Up to 3 current transducers can also be connected here, 3 Input 24 V DC positive from a separate 24 V supply unit in the TEC cabinet (connected at delivery). This power feeds the cabinet light. 4 Output 24 V DC positive from X3:3. This terminal is used to energise 4-20 ma sensors. 5 Input 24 V DC negative. 6 Output 24 V DC negative from X3:5. 1ZSC 954003-006 en, Rev. 2 17

1.4.2.2 Processor LEDs: green and red RS 232 DIN connection for system administration (loading new code) Fibre optic input, ST connector from station PC Fibre optic output, ST connector to station PC RS 485 connection to display board and motor relay board via terminal group X11 tec_0096 tec_0050 Terminal group X11 1-4 Shall not be used (RS 422 connection) 5 RS 485 connection A to motor relay board. 6 RS 485 connection B to motor relay board. 18 1ZSC 954003-006 en, Rev. 2

1.4.2.3 Analogue input 4-20 ma 4-20 ma input via terminal group X11 tec_0034 tec_0050 The sensors are calibrated and assigned to their terminals at delivery, see sections 9.1 Ordering data and 6.7.2 TEC. If a new calibration is needed, see TEC Monitor manual, 1ZSC 954003-012. The 3 current transducers can take the 24 V DC supply from X3:1 and 2. Power supply for other sensors that requires 24 V DC shall be provided by the transformer manufacturer. Terminal group X21 1 2 Current High Voltage 3 4 Current Low Voltage 5 6 Current Tertiary Voltage 7 8 Tap-changer temperature from moisture sensor (can have other power supply than 24 V DC) 9 10 Tap-changer moisture in oil sensor (can have other power supply than 24 V DC) 11 12 Transformer temperature from moisture sensor (can have other power supply than 24 V DC) 13 14 Hydrogen (can have other power supply than 24 V DC) 15 16 Transformer moisture in oil sensor (can have other power supply than 24 V DC) 4-20 ma sensor 24 V tec_0015 1ZSC 954003-006 en, Rev. 2 19

1.4.2.4 Temperature input Pt 100 In order to improve the measuring accuracy, Pt 100 temperature sensors are connected directly to the front of the board, not via terminals at the bottom of the cabinet. This connection is designated Terminal group X31. If one or more extra boards are needed, they will be placed after the standard boards and the terminal groups will be designated X32, X33 etc. Pt 100 sensors are calibrated at delivery and need no recalibration. Terminal group X31 Pt 100 100 Ω tec_0016 Current Feed Measure Top oil Bottom oil Air in shadow 1 5 9 13 2 6 10 14 3 7 11 15 4 8 12 16 tec_0051 tec_0034 Position X31 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Air in sun Terminal group X32 Pt 100 100 Ω tec_0016 Current Feed Measure Tap-changer 1 Tap-changer 2 Tap-changer 3 1 5 9 13 2 6 10 14 3 7 11 15 4 8 12 16 tec_0051 tec_0034 Position X32 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Tap-changer 4/Core yoke 20 1ZSC 954003-006 en, Rev. 2

1.4.2.5 Digital input tec_0034 tec_0046 The digital input board interprets relay signals of two different types: Function confirmation that a device is running properly, where an open relay contact means that the device is not running and a closed contact indicates that it is running. Example: Oil flow indicator in a cooler circuit. In case of TEC cooling group control the feedback from each cooler group needs to be connected to TEC. The input shall be placed first of all input X41:1 and following. Warning, alarm and trip devices, where an open relay contact means a normal function and a closed contact shall release a warning, alarm or trip signal. Example: Sudden pressure relay. For each contact connected to the digital input board, the type is defined by data entered to the ordering data sheet. This information is then stored if an interface exists. (See the interface manual.) +24 V +24 V (+24 V) Neutral Test = 24 24 0 Terminals Terminals and boards Sensor contacts tec_0012 1ZSC 954003-006 en, Rev. 2 21

Terminals 1-8 are available for warning and alarm contacts, e.g. the oil level detector and Bucholz relay (warning levels). Any of these eight terminals can also be used for function confirmation type contacts. In that case, the related contacts from each cooler group shall be connected in series to the same terminal, e.g. the auxiliary contact on a fan motor contactor and the oil flow indicator of the same cooler group. When TEC controls the coolers, each cooler group shall give a function confirmation signal to the digital input board. The digital input board feeds +24 V DC to the terminal and also measures the voltage at the terminal. As long as the sensor contact is open, the voltage is maintained and the status of warning/alarm signals is ok. The status of function signals is not running, which also is ok as long as the cooler group is not switched on. When a sensor contact is closed, the voltage supply from the board cannot maintain the 24 V, the measured voltage drops to zero and for warning/alarm inputs, an error signal is released. Function inputs change status to running. The warning/alarm signal is released (or the function changes to running ) when the measured voltage is below 8 V. +24 V +24 V Neutral +24 V (+24 V) Neutral 110 110 24 0 Terminals and boards Trip relay coil tec_0013 +110 V tec_0014 +110 V Terminals 9-12 are available for sensor contacts which normally are used to trip the transformer, e.g. sudden pressure relay and Bucholz trip contacts. This example shows how two sensor contacts, a 110 V battery and the trip relay coil are connected. As long as all sensor contacts are open, the measured voltage is 110 V and the status is ok. If one contact closes, the 110 V circuit is closed, the current through the trip relay coil trips the transformer and the measured voltage at the terminal drops to zero. The battery voltage also disappears from the other terminals, but there the 24 V supply from the board maintains the measured voltage above 8 V. Any of the twelve terminals will activate a warning, an alarm or a trip signal from TEC via the output auxiliary relay contacts of the Control and output board, section 1.4.2.6. If more than 8 warning/alarm/function or 4 trip sensors are used, one or more extra boards are needed. The terminal groups will be placed at the lower terminal row and designated X42, X43 etc. 22 1ZSC 954003-006 en, Rev. 2

Terminal group X41 Each sensor is connected to one of the terminals 1-12 and one of the neutral terminals 17-24. 1-8 Input warning/alarm and function sensor contacts. 9-12 Input trip sensor contacts. 13-16 Shall not be used. 17-24 Input neutral. Each terminal number represents two terminals, one at the upper side and one at the lower side. 25 Shall not be used. 26 Input positive DC from battery and trip relay coil according to sketch above. Voltages above +220 V DC and negative voltages are not permitted. 27-28 Shall not be used. 29 Input neutral from battery and trip relay coil. 30 Shall not be used. See chapter 1.6 for the trip and alarm/warning functionality. 1ZSC 954003-006 en, Rev. 2 23

1.4.2.6 Control and output tec_0048 tec_0046 This board is used to make relay signals. Terminal group X51 1 Output disconnectable terminal in series with terminal 14 (Disconnected in downwards position.) 2-3 Input voltage measurements. Nominal voltage 85 145 V AC. Neutral on 3. 4-6 Input tap-changer position transmitter, 4 = max position, 5 = moving contact, 6 = min position. R tot 80 Ω. 7-9 Output. Not used in this version. 10, 12 Output dry contact for warning 11, 12 Output dry contact for alarm 13, 1 Output dry contact for trip. This output also have a contact that can be disconnecte at terminal 1. These 7 8 9 10 11 12 13 1 contacts are wired to the digital board to get one trip output on X41:26 and 29. 14 tec_0017 Dangerous voltage! WARNING Permitted load (breaking capacity) on output terminals: AC 250 V 8 A DC 125 V 0.1 A L/R = 7 ms DC 30 V 5 A 24 1ZSC 954003-006 en, Rev. 2

1.4.2.7 Motor relay TC180 Power +24 V 0 RS 485 A RS 485 B 1 2 3 4 Cooler group tec_0053 5 6 LEDs tec_0055 tec_0054 The motor relay board TC 180 is placed in the transformer control cabinet. All fans and pumps of one cooler group shall be connected so that they are started by one relay output. Up to six separate groups can be controlled. If the RS 485 connection to TEC is lost, all relays will close automatically one by one with 10 seconds intervals. It is recommended to supply the motor relay board with 24 V DC from the transformer cabinet to ensure that all motors start even if the entire connection to TEC is broken. If the power supply to TEC is disconnected the motor relay board starts all cooler groups. To avoid this when the transformer is out of service, first disconnect contact with the 24V supply to the motor board. The power supply to TEC should also be connected before the 24V power supply to the motor board to avoid that the coolers starts. A traditional top oil thermometer is also recommended to be used as a back-up together with this version of TEC. It shall be set to start all cooler groups 5 ºC above the highest start temperature in TEC. The permitted load on the relays is the same as on output terminals of the control and output board. 1ZSC 954003-006 en, Rev. 2 25

1.4.2.8 Alarm box Power +24 V 0 RS 485 A RS 485 B 1 2 3 4 Alarm signals tec_0053 5 6 LEDs tec_0055 tec_0054 The alarm box can be used get dry contact output from specific alarms in TEC. The alarm box can be placed in the transformer cabinet. The two extra shielded cables in the big cable between TEC and the transformer cabinet. There are 2 different alarm boxes available. No connection should be made to the signals that not used. Permitted load (breaking capacity) on output terminals: AC DC DC 250 V8 A 125 V0.1 A L/R=7 ms 20 V 5 A Only one type of alarm relay box can be used. The alarm box, TC182, can either be placed in the TEC or in the transformer cabinet. The power suply can be taken from either the 24 V output from TC110 or any other 24 V source. The communication cables can be parallel wired with the communication to the cooler box. Closed relay is represented by a lit LED. 26 1ZSC 954003-006 en, Rev. 2

TC182 24 V 0 V On Common A Data communication 1 B Top-oil alarm 2 Hot-spot alarm 3 OLTC temperature 4 OLTC maintenance 5 Cooler error 6 Loss of com to TEC Top-oil alarm Hot-spot alarm OLTC temperature OLTC maintenance Cooler error Loss of comm. to TEC Top-oil temperature alarm Hot-spot temperature alarm OLTC temperature or OLTC temperature balance Exchange or service is needed Cooler problem or transformer temperature balance event No communication between alarm box and TEC (for example wiring, power or system failure of TEC). The relay is closed when the box have power but no communication to TEC. The other relays will be open. There is a 20 second delay. 1.4.2.10 Display The display board TC 170 is connected to the processor board at delivery. tec_0073 tec_0057 1ZSC 954003-006 en, Rev. 2 27

1.5 Performed tests 1.5.1 EMC (Electro Magnetic Compability) tests Immunity according to EN 61000-6-2:1999 Radiated RF field IEC/EN 61000-4-3 (1995), ENV50204 (1995) Conducted RF voltage IEC/EN 61000-4-6 (1996) Fast transient/burst IEC/EN 61000-4-4 (1995) Electrostatic discharge (ESD) IEC/EN 61000-4-2 (1995/96) Surge IEC/EN 61000-4-5 (1995) LF magnetic field 1 IEC/EN 61000-4-8 (1993) Additional immunity tests Damped Oscillatory Wave 1 IEC/EN 61000-4-12 (1995), SS436 15 03 Spark 1 SS436 15 03 Power voltage variations 1 IEC SC77AWG 6 (info. Annex) Emission according to EN 50081-2:1993 Radiated emission CISPR 11 (1997), EN 55011 (1998) Conducted emission CISPR 11 (1997), EN 55011 (1998) 1) This method is not within the scope of the laboratory accreditation. Emission Port Class Limits Result 1 Radiated emission Enclosure A limits of EN 55011 increased by 10 db for 10 m measure distance in accordance with EN 50081-2 Passed Conducted emission AC mains A limits of EN 55011 Passed Immunity Immunity port Process I/O ports Mains port 1) Passed = Complied with the specification. Failed = Did not comply with the specification. See relevant chapter for details. Criteria, see chapter 4.4 Criteria for approval. Earth ports Result/ Criteria 1 Radiated RF fields 15 V/m - - - Passed/A Conducted RF voltage - 10 V 10 V 10 V Passed/A Electrostatic discharge 8 kv contact 4 kv 4 kv 4 kv Passed/A 15 kv air Surge pulse - 4 kv (CM) 4 kv (CM) - Passed/A 2 kv (CM) Power frequency magnetic field 1000 A/m - - - Passed/A Power voltage variations - - -/+ 10 %, 15 s - Passed/A Damped oscillatory wave- 2.5 kv 2.5 kv - Passed/A Fast transient/spark - 4 kv - 8 kv 4 kv - 8 kv - Passed/A 28 1ZSC 954003-006 en, Rev. 2

1.5.2 Mechanical tests, vibration and seismic The TEC unit manufactured by ABB in Sweden have been subjected to mechanical testing as specified in chapter 3. The results of the testing are given below: Test Specifications Severity Result Vibration IEC 60255-21-1 IEC 60068-2-6 10-150 Hz, 2 g, 20 sweep cycles OK Bump IEC 60255-21-2 IEC 60068-2-29 10g, 16 ms, 6 x 1000 bumps OK Shock IEC 60255-21-2 IEC 60068-2-27 15 g, 11 ms, 6 x 3 shocks OK Seismic IEC 60255-21-3 IEC 60068-2-6 1-35 Hz, 7.5 mm/2 g, 1 sweep OK OK: No malfunctions was observed during the test and no damage was observed after the test. 1.5.3 Climate tests Test Severity Duration Standard Dry heat Operational +85 C 72 hours IEC 60068-2-2, Test Bd Cold Operational -40 C 72 hours IEC 60068-2-1, Test Ab Change of temperature Operational -40 to +70 C 3 cycles t = 2 h 3 C/min IEC 60068-2-14, Test Nb Damp heat steady state Operational +40 C, >93 % non condensing 4 days IEC 60068-2-3, Test Ca Damp heat cyclic Operational +25 to +55 C, >93 % condensing 6 cycles à 24 hours IEC 60068-2-30, Test Dd 1ZSC 954003-006 en, Rev. 2 29

1.6 Trip, alarm and warning output from TEC 1.6.1 Output signals from TEC cabinet Optic fibre, all information Sum Trip signal from X41 from all signals connected to X41 trip positions and the internal TEC trip from X51. The internal TEC trip can be disconnected. One Alarm signal from TEC X51. Top oil, hot-spot contact exchange, tap-changer temp etc. One Warning signal from TEC X51. Top oil, hot-spot, tap-changer service, tap-changer temp etc. Alarm box Relay box with 6 dry contacts to distinguish between Alarms 1.6.2 Alarm/Warning output options Alarm/Warning option 1 From devices connected to TEC there will be one alarm signal from X51:11 and 12, and the warning signal from X51:10 and 12. Alarms and warnings from TEC functions will also be connected to these contacts. Via the optic fiber the interface PC will have the details about the alarm and warning signals from the devices and TEC in the event log. Option 1, TEC option Buchholz Device Connected to TEC Connected devices, hot-spot, top oil and other alarm and warnings from TEC Terminal X51 Substation Control 2 cables for Alarm and Warning from TEC Gets a Alarm or Warning from contacts Gets a Alarm or Warning from TEC Details found in TEC 10 11 12 Warning output Alarm output 30 1ZSC 954003-006 en, Rev. 2

Alarm/Warning option 2 No devices connected to TEC. Alarms and warnings from TEC functions will have the alarm signal from X51:11 and 12, and the warning signal from X51: 10 and 12. Via the optic fiber the interface PC will have the details about the alarm and warning signals from TEC in the event log. Option 2, TEC option with traditional contacts Buchholz Top oil Hot-spot Customer connects in cabinet Hot-spot, top oil and other alarm and warnings from TEC Terminal X51 Substation Control 2 cables for Alarm and Warning from TEC Cables from all protection devices Gets a Alarm or Warning from TEC TEC gives details from TEC Alarm/Warnings 10 11 12 Warning output Alarm output 1.6.3 Trip output options Trip option 1 No trip devices connected to TEC. Trip from TEC functions gives signal from X41:26 and 29. The customer connects this signal as any other device. Via the optic fiber the interface PC will have the details about the trips from TEC in the event log. Trip option 2 No trip devices connected to TEC. Trip from TEC functions not used. No information about the trips in TEC event log. Option 1 with TEC trip device from TEC Traditionally but with the trip from TEC hot-spot and top oil added as an extra device. Option 2 as today on transformer Buchholz Pressure relay Relief vent Top oil Hot-spot Buchholz Pressure relay Relief vent TEC top oil and hot-spot trip Customer connections 26 29 X41 X41 26 29 13 1 X51 14 Customer connections Substation Control 1 cables for Trip from TEC (option 1) Cables from all protection devices TEC gives details from TEC Trip (option 1) 1 Output disconnectable terminal in series with terminal 14. 1ZSC 954003-006 en, Rev. 2 31

Trip option 3 From trip devices connected to TEC there will be one trip signal from X41:26 and 29. If the TEC trip is disconnected at terminal X51:1 this signal will not be integrated in the trip sum signal. Via the optic fiber the interface PC will have the details about the trip signals from the devices and TEC in the event log. Trip option 4 From trip devices connected to TEC and the internal TEC there will be one trip signal from X41:26 and 29. Via the optic fiber the interface PC will have the details about the trip signals from the devices and TEC in the event log. Option 3 TEC solution Option 4 TEC solution with TEC trip device Resistor Device Resistor Device 1 Top oil Device 2 Hot-spot 13 1 TEC X51:1 disconnected + - Connected in TEC cabinet, trip traditional way to customer, but all devices connected. TEC Hot-spot & top oil trip + - Connected in TEC cabinet, trip traditional way to customer, but all devices connected. Substation Control 1 cables for Trip from TEC TEC gives details for all Trip Substation Control 1 cables for Trip from TEC TEC trip included TEC gives details for all Trip 1.6.4 Connection of devices in parallel both traditionally and to TEC Alarm/Warning devices Below figure shows how alarm/warning devices can be connected the traditional way in parallel with TEC. If the voltage in the station alarm/warning circuit is >24V no diode is needed in the traditionally alarm/warning circuit. Same common as in Trip circuit 24V 24V TEC Alarm/Warning device 1 Alarm/Warning device 2 If V > 24V no diode is needed V V Traditional connection, but sometimes with diode 32 1ZSC 954003-006 en, Rev. 2

Trip devices Below figure shows how warning/alarm devices can be connected the traditional way in parallel with TEC. Observe that a diode is needed in the traditionally trip circuit. If devices are connected both to TEC and the traditional way Same common as in Alarm/Warning circuit 24V 24V TEC Trip device 1 Trip device 2 Traditional connection, but always with diode Extra to TEC to get out one sum Trip signal even if TEC is dead 1ZSC 954003-006 en, Rev. 2 33

1.7 Ordering data The transformer manufacturer specifies TEC on an ordering data sheet with embedded guidance. The folders in the Excel sheet that should be filled in are: Order data 1, Functions Hardware Order data 2, Protection Sensors Order data 3, Software Order data 4, Cooling control Cells with a red mark in the corner contain help. Part of page 1 is shown here, page 2 with data on sensors is shown in 2.1. Additional data from the transformer design database are also used to configurate a mathematical model of the transformer in the TEC system software. tec_0081 1.7.1 Load test In case data from the heat-run test of the transformer deviate from calculated values given in section 1.7 Ordering data, the new values shall be added to the model of the transformer in TEC. In version 1.0, this is done by sending a revised ordering data sheet to ABB, where the program code can also be updated. (See the interface manual.) 34 1ZSC 954003-006 en, Rev. 2

2 Installation manual 2.1 Connection table Already from the Excel order data sheet under Order data 2 Protection Sensors it is possible to see how the sensors shall be connected. The other connections can be found in section 1.4.2 Electronic boards and terminals. tec_0089 A similar table will also be sent with the order confirmation. 1ZSC 954003-006 en, Rev. 2 35

2.2 Sensors Sensors are normally included in the delivery, see 1.7 Ordering data. Connection of the cable shield is described in 2.3 Cables. 2.2.1 Air temperature Pt 100 sensor for air temperature in sun and shadow. The sensor in the shadow must not be influenced by the radiated heat from the transformer. A Pt 100 sensor that is replaced, automatically starts to work after approximately 30 seconds. The bushing that is included in the delivery is for cable diameter 4 8 mm. If a larger cable diameter is used, it should be provided by the customer. Height with cover: 44 Ø 4.5 (2x) Temperature input Pt 100 50 46 36.5 66 T ( C) Pt 100(Ω) -40 84.3-30 88.2-20 92.2-10 96.1 0 100.0 10 103.9 20 107.8 30 111.7 40 115.5 50 119.4 60 123.2 70 127.1 80 130.9 90 134.7 100 138.5 110 142.3 120 146.0 130 149.8 140 153.5 150 157.2 160 160.9 Shadow sensor 9 11 10 12 Sun sensor 13 15 14 16 tec_0104 36 1ZSC 954003-006 en, Rev. 2

2.2.2 Oil temperature 7/8-14UNF2 88 D=12.21±0.05 169 KR 1 166 D=14 tec_0059 Pt 100 sensor for oil temperatures at the transformer top and bottom and in the tapchanger. The thermometer pocket is included in the delivery of the temperature sensor. Order sensor for the tap-changer together with the tap-changer. Recommendations about placement of the thermometer: - Should be placed in level of the lower spacer ring (to avoid the cooler non moving bottom oil). - Should be placed not to far away from the cooler /radiator outlet (to measure in moving oil). 2.2.2.1 Use of TEC bottom oil sensor The TEC bottom oil sensor should not be used in the calculations from the heat run test but the temperature should be noted. The calculation of average oil temperature etc. should be carried out in the normal way. TEC will for OF- and OD-cooled transformers in service calculate the hotspot from the TEC bottom oil thermometer and the calculated values from the heat run test. The bottom oil sensor shall be assembled at a position where the reading represents the temperature of the oil entering the windings. 84 84 1 3 2 4 Conductor no. in 3.2.4 Temperature input Pt 100 tec_0060 1ZSC 954003-006 en, Rev. 2 37

2.2.3 Current transducer The current transducer is a 4-20 ma sensor that is connected on the cable from the transformer CT (current transformer). The sensor requires a 24 V DC supply to be connected in series with the signal. The 24 V DC power supply from X3:1 and 2 can be used. The cable from the CT should sometimes make more then one-turn trough the current transducer. The amount of turns can be found on the order data sheet or on the sign inside of the cabinet door. The current transducer can be calibrated from the interface. (See the interface manual.) If only one current transducer is used, the two current transducers should be placed on the same CT for backup purposes. Examples on CT locations in the transformer I I TEC Current transducer in the transformer cabinet I TEC = 4 + 16c I ma c = combined ratio of the current transformers tec_0018 70 56 32 tec_0061 2.2.4 Hydrogen gas in oil HYDRAN is a suitable sensor for hydrogen gas. Other sensors giving a 4-20 ma signal can also be used. The Hydran detector gives a signal proportional to the hydrogen equivalent in the transformer oil. The hydrogen equivalent includes the content of hydrogen (H 2 ) and fractions of the hydrocarbons (C 2 H 2, C 2 H 4, etc.) and carbon monoxide (CO) in the transformer oil. If needed, the sensor reading can be calibrated from the interface. (See the interface manual.) 2.2.5 Moisture in oil sensor Moisture in oil sensor giving an output of 4-20 ma can be used. The output can be ppm, water activity or RH %. If the output is in ppm, the temperature output (4-20 ma) from the sensor does not need to be connected to TEC. 38 1ZSC 954003-006 en, Rev. 2

2.3 Cables and earthing 2.3.1 Pt 100 Fibre optic cable and cables to the sensors are normally included in the TEC delivery with lengths as specified in 9.1 Ordering data. All cable shields shall be connected to the TEC cabinet earth in one of the following ways: With a Roxtec sealing system at the entrance of the cabinet. With an EMC cable gland at the entrance of the cabinet. At the common earth bar in the cabinet. The length of the strand from the cable/ shield to the earth bar shall not be more than 50 mm. The sensor cable shields shall be connected to earth at one point only and thus not be connected to earth at the sensors. Shielded cable with four conductors in twisted pairs. One pair to feed current and one pair to measure resistance / voltage drop. Recommended conductor area 0.5 mm 2 (max 1.5). 2.3.2 4-20 ma and Digital in 2.3.3 RS 485 Shielded cable with two conductors in twisted pairs. Recommended conductor area 0.5 mm 2 (max 2.5). Shielded cable with two conductors in twisted pair. Recommended conductor area 0.5 mm 2. 2.3.4 Fibre optic The TEC cabinet is connected to the station PC with a double fibre optic cable. Cable diameter 62.5 / 125 µm with ST contacts. Cable length up to 1 km with max attenuation 4 db/km. The cable shall be handled with care: Max. allowable tensile load (N) during installation 3000 in service 1500 Min. bending radius (mm) during installation 130 in service 80 Crush resistance (N/cm) briefly 400 permanently 200 Impact resistance (impacts) Wp=4.41 Nm/r=25 mm 30 Temperature range ( C) during installation -10 to +50 in service -25 to +70 in storage -40 to +70 1ZSC 954003-006 en, Rev. 2 39

2.3.5 Cable entry and Roxtec Cables enter the cabinet at the bottom via a flange that is drilled and provided with cable glands at the transformer assembly, or via a Roxtec sealing system. Dimensions are given in 1.4.1 Cabinet. Use the original manual for guidance at installation work. tec_0072 2.4 PC The PC is normally part of the TEC delivery. See the interface manual, if existing. tec_0062 40 1ZSC 954003-006 en, Rev. 2

3 Operating manual 3.1 Start sequence The TEC processor starts automatically when it is connected to voltage. (The power supply to TEC should be connected before the 24 V power supply to the motor board to avoid that the coolers start immediately.) The TEC PC should be started after the TEC processor. (See the interface manual.) 3.2 Display on cabinet A status light, a display and a push-button are assembled on the front of the cabinet. One push at the button wakes up the display and the information scrolls slowly. A second push stops the scroll and subsequent pushes advances the information step by step. Press the button for three seconds to return to automatic scrolling. Five minutes after the last push, the display turns off. tec_0063, tec_0073 tec_0064 - tec_0071 A TOP OIL Top oil temperature B1 HOT-SPOT HV Hot-spot temperature high voltage winding B2 HOT-SPOT LV Hot-spot temperature low voltage winding C BOTTOM OIL Bottom oil temperature D LOAD I/ Irat Load I/I rated (highest of LV and HV) E OLTC POSITION Tap-changer position (numbers from 1-n) F OLTC TEMP1 Temperature of first tap-changer G HYDROGEN H2 Hydrogen gas In oil Moisture in trafo Moisture in oil in the transformer Moisture in OLTC Moisture in oil in the tap-changer E, F, G and moisture readings are only displayed when applicable. 1ZSC 954003-006 en, Rev. 2 41

3.2.1 Status light Red, alarm or trip Yellow, warning Green, normal The same colour code is used in the station interface 3.3 Warning, Alarm and Trip signals TEC can give a warning, alarm and trip signal. The warning signal could be seen as an early alarm signal. The alarm signal should be similar to the normal alarm signal The trip signal created by TEC is only the top oil and hot-spot trip. This trip signals can be disconnected at the terminal. 3.4 TEC during transformer test TEC can be connected during test of the transformer. If it is switched off, the coolers will be started automatically unless their power supply is also switched off. 3.5 Sensor failure There is a sensor back-up in TEC in the case of a sensor failure. If the reading from a Pt100 sensor is out of range (-50 150 C) for 1 minute a back-up will take place described below. A warning signal on the status lights and in the station PC. If the Pt 100 sensor is replaced it will start to work after approximately 30 seconds. A 4 20mA sensor that is out of range if the reading is <3 ma or >22 ma - then it will be a warning signal on the status lights and in the station PC. The false sensor reading will not be displayed. If the sensor is replaced it will start to work after 30 seconds. For the current sensors, see also the logic below. Top oil thermometer failure If the sensor fails, the top oil is calculated based on the bottom oil temperature. At stable conditions the calculated temperature will be rather close to the real one. Although at rapid load increase the calculated top oil temperature will increase much quicker then the real temperature. To avoid a to early trip in this case the top oil trip is disabled, although alarm and warning will still work. There will be a warning for sensor failure. Θ Top = Θ Bot + 2[ Θ imr - Θ br ]K y Bottom oil thermometer failure If the sensor fails, the bottom oil is calculated based on the top oil temperature. There will be a warning for sensor failure. Θ Bot = Θ Top - 2[ Θ imr - Θ br ]K y 42 1ZSC 954003-006 en, Rev. 2

Both top and bottom oil thermometer fails If both sensors fail, there will be an alarm for sensor failure in TEC. Ambient air thermometer failure If the shadow sensor fails, the value from the sun sensor will be displayed and used for the calculations. If the sun sensor fails, the value from the shadow sensor will be displayed. If one sensor fails there will be a warning. If both sensors fail there will still be a warning but the output from the sensors will be the latest readings before failure. Current sensors There are three different types of behaviour in case of sensor errors. A two-winding transformer sensor error will be compensated by calculation of the faulty current, based on the other current sensor. The calculation is based on the remaining current, the transformer ratio and the tap-changer. For all other connection types there will not be any current calculation. The faulty sensor will display 0. For autotransformers a current sensor failure on the series winding will result in a current reading of 0 from both current sensors. If the current sensor on the LV side or common winding fails the output from this sensor will be 0, but the output from the series current sensor will be correct. If one current sensor fails there will be a warning. If both sensors fail there will be an alarm. 3.5.1 Sensor failures influence on functions Hot-spot temperature calculation The hot-spot temperatures for the high-voltage and low-voltage winding is always calculated. If a thermometer or current transformer sensor fails the lost value will be calculated by the formulas in the previous sections and will be used for the hot-spot calculations. Ageing If the hot-spot temperature of the hottest winding cannot be calculated, e.g. because of a current transformer failure, the second hottest winding will be used for the ageing calculation. Cooling control If the hot-spot temperature of the hottest winding cannot be calculated, e.g. because of a current transformer failure, the second hottest winding will be used for the cooling control. 1ZSC 954003-006 en, Rev. 2 43

3.5.2 Other back-ups in case of failures PC problem If the PC is switched off or stops working the consequences are: No historical data will be stored Alarms and warnings can t be reset. The TEC cabinet functionality is not affected except for the small correction of the TEC clock. Cooling control back-up If the TEC for some reason stops working or the connection between TEC and motor board is disconnected the consequences are: The motor control board will start all cooling, with a 10 sec time delay between each of them If the 24V power supply to the motor board or the motor board stops working. The traditional top oil thermometer will start all coolers 44 1ZSC 954003-006 en, Rev. 2

4 Maintenance and service manual No routine maintenance on TEC is needed 4.1 Loading of new program in TEC See COM03-029 TEC Application and parameter load instruction. (The product information is attached in the station interface TEC documentation file.) 4.1.1 Hardware needed and connections Connecting the PC to the TEC TC120 board according to figure. Monitoring cable. Contacts on monitoring cable. Contact Connection of the cable to the TC120 board. The other end of the cable should be connected to the COM port in the PC. 1ZSC 954003-006 en, Rev. 2 45