BushingGard TM Installation and Operation Manual, Version 2.1b Condenser Bushing Insulation Monitoring

Transcription

1 BushingGard TM Installation and Operation Manual, Version 2.1b Condenser Bushing Insulation Monitoring Instructional Manual

2 Page 2 Effective: May 2007 BushingGard TM Installation and Operation Manual, Table of Contents 1 Description General Basics of Operation Important Features and Options Specification Display, Keypad and External connections Alarms Trend calculation Gamma-versus- Temperature Coefficient calculation Continuous Watch Feature Schedule Device Address Self-test and Self-calibration Auxiliary Input Measurement Suspend Software Installation Application Issues Type and specific of equipment to monitor Noise and grounding aspects Device location and environmental issues Networking and Communicating to the device BushingGard Set contents BushingGard connection diagram Installation Important Safety Notes BushingGard Installation Bushing, Temperature and Load sensors Powering up the monitor and energizing transformer Startup General Step 1 Establishing communication to the monitor Step 2 Setting the Monitor Common Settings Tab...25

3 Page 3 Effective: May 2007 BushingGard TM Installation and Operation Manual, Set1 (2) Tab Auxiliary Inputs Tab Step 3 Balancing the Monitor Step 4 Taking Several Readings Appendix1. Device Setup via Keypad Keypad Setup via Keypad Appendix 2. Troubleshooting... 57

4 Page 4 Effective: May 2007 BushingGard TM Installation and Operation Manual, 1.1 General 1 Description Up to 35-45% of all transformer s electrical failures are associated with bushing failures, mostly in bushing insulation. Moisture ingression, oil deterioration and paper aging lead to an increase in bushing power factor, insulation overheating and fast degradation followed with insulation breakdown. As a part of degradation process, partial discharges occur at some time, including early, stages of insulation degradation causing accelerated rise of power factor and insulation destruction. Such discharges may cause treeing, puncture of several paper layers or/and may be observed along the porcelain surface at the bushing bottom when oil sludge was accumulated there. Deterioration in the insulation core is usually accompanied with an increase in bushing capacitance C 1 (between HV rod and test tap). At the initial stages of destruction the changes in power factor prevails, then the change in capacitance becomes evident. The presence of a test (potential) tap creates a convenient possibility to monitor on-line the state of bushing insulation for that insulation part that corresponds to C 1. Note: combining power frequency measurements with radio frequency partial discharge measurements (sensors produced by EEPD allow that) increases additionally the sensitivity of monitoring and reliability of diagnostics. Based on a previous experience, change in current about 1%-2% is considered as a sign of essential deterioration, about 3%-5%- of very serious situation and above 6%-8%- of catastrophic situation with fast impeding explosion. The monitoring has, respectively, to be sensitive enough to detect the changes in current of %. Respectively, the current measuring circuit has to be very accurate and stable. For additional increase in its sensitivity the monitoring device measures the sum of bushing currents for three-phase set of identical bushings that is normally close to zero and may be brought to zero with artificial balancing at initial commissioning of the installation. The output signal in such installation was named Gamma. It was shown that at changing of parameters in one bushing Gamma reproduces precisely the relative change in the insulation current of this bushing: I γ = = ( tan δ ) + ( C Io Co ) 2 2 where I is the change in the current through insulation, caused by an appeared defect, I 0 is the current through insulation prior to this defect (more correctly, at the moment of the monitoring system commissioning), tan reflects a change in power factor of the main bushing part related to the capacitance C 1, and C is a change in this capacitance over its initial value C 0. Note: If changes occur simultaneously in two or three bushings in the set the Gamma value will

5 Page 5 Effective: May 2007 BushingGard TM Installation and Operation Manual, be a vector sum of all changes. BushingGard is a stand-alone microprocessor-controlled monitoring device specially designed to monitor the Gamma value in 60/50 Hz sets of bushings (25 Hz is also applicable), to store the information in its internal memory and to provide an alarm signal based on Gammaparameter characteristics at an early stage of insulation degradation. Diagnostic functions that are built in the firmware allow for: Calculations of capacitance and relative Tan of each bushing in a three-bushing set. Determining temperature coefficients of Tan of each bushing. BushingGard has a temperature input for hot oil temperature allowing reveal bushing characteristics temperature dependencies. BushingGard has several interfaces that allow for easy implementation into an alarm or SCADA system and communicating to the device locally or within existing LAN or RS-485 networks: Three form-c dry relay contact providing Red and Yellow and device malfunction indication. Optically isolated RS-485 interface allowing for device configuration and data download into PC. USB port for local communication. Communication interfaces based on Modbus RTU or Modbus TCP protocols allowing for networking with an existing Modbus or Modbus over TCP/IP networks. PD ports provide for measurement of partial discharges on periodical basis with any appropriate external PD instrumentation. Modbus RTU communication protocol can be used to build BushingGard into a high-level software program using standard commands. BushingGard is supplied with database software allowing for automated communication to a device or several devices for data acquisition and analysis. The software allows for either direct network or dial-up connection to a device by a regular telephone land or cellular line. 1.2 Basics of Operation BushingGard has 6 inputs (A1, B1, C1 and A2, B2, C2) for signals from two sets of bushing sensors. A signal contains both power frequency (50 or 60Hz) current and high frequency (above 200kHz) pulses reflecting partial discharges. At the input of BushingGard, PD component is filtered out and passed to PD ports (BNC connectors). Power frequency signals from all three bushings are summarized on the summarizing resistor. At device on-site commissioning this sum (Gamma - G) is balanced close to zero (<0.1% of test tap current) by digital potentiometers. Over time, while bushing(s) insulation is worsening, the active and/or

6 Page 6 Effective: May 2007 BushingGard TM Installation and Operation Manual, reactive components of bushing current change thus are disturbing the initial balance. The value of unbalance, its temperature dependence and trend over time are used as indicators of impending bushing problem. Alarm will be produced, if any of alarm thresholds is exceeded. The currents from each bushing are also analyzed and Tan and capacitance of a bushing are calculated. Before each measurement BushingGard performs a self-calibration and self-test and also tests signal s magnitude. In case of successful self-test, device Status relay is powered up and normally opened contact will be closed indicating normal device operation. If any problem is detected, the relay will be de-energized. Normally Opened dry contacts will be opened and an appropriate message will appear on BushingGard display. Loss of power will be indicated in the same way by de-energizing Status relay and opening normally opened contacts. Data are compared to preset warning and alarm thresholds after each measurement. If a Warning threshold has been exceeded, the Yellow Warning LED will be turned on and Warning relay operated. If the Red Alarm level is exceeded the BushingGard will trigger an additional measurement in five minutes and, if confirmed, the Alarm Red LED will be turned on and the Alarm relay dry contact will be opened. If an Alarm level is detected, alarm data will be stored in the event memory. Measurements can be performed by time schedule (up to 8 tests per day) or in specified time intervals (from 1 minute to 11hours 59 minutes). A schedule is stored in the device memory and measurements will be performed accordingly. Recommended (default) are eight measurements per day. Continuous Watch feature is enabled between scheduled measurements. The device measures parameter G every five minutes. If an alarm condition is detected between the scheduled measurements, the BushingGard triggers a full measurement and displays an alarm, if confirmed. Gamma temperature coefficient (GT) and trend (GTr) are calculated after each measurement based on configurable number of days (not less then 15) using a time sliding window. Calculations require at least 40 data points over sliding window time. If data is not sufficient calculation is skipped and a parameter stays zero. Calculation Gamma temperature coefficient also may be skipped if Gamma correlation to temperature is below 0.5. After each measurement the device scrolls on display current data: Gamma, Gamma s phase angle, temperature coefficient and trend Diagnostics Bushing s Tan and capacitance Input signal s magnitudes Date and Time stamp and temperature at the measurement. Alarm status.

7 Page 7 Effective: May 2007 BushingGard TM Installation and Operation Manual, 1.3 Important Features and Options Specification Small footprint 6 x10.5 x1.5, flashmounted Enclosure Power Source (DC option should be specified at the time of order.) Power Consumption Fuse (inside device on printed board) Fuses on the back panel Temperature Range (None-condensing) External Connections Input Channels (power frequency and PD) from bushing taps 6 Test tap current PD outputs from bushing sensors (Isolated for 1.0 kv, BNC connector) 6 Temperature Inputs (100 Ohm RTD) 3 Alarm C-form dry relay contacts (Red, Yellow alarms, device malfunction, fully configurable) RS-485, optically-isolated for 2kV 1 USB port 1 Internal data memory Display Keypad LEDs: Setup Applications NEMA 4 (4X) VAC 60 (50) Hz or VDC 5 W (Max) 0.1A, 5x20mm 1A, 5x20 mm C C Terminal blocks ma RMS 3 220V, 12 A 32MB/ over 10years Bright graphic 4 arrows and 4 functional keys 3 LEDs (Status, Warning, Alarm) Fully configurable from keypad and PC Two three-phase bushing sets of HV transformer/autotransform er, or sets of Current or Potential transformer or

8 Page 8 Effective: May 2007 BushingGard TM Installation and Operation Manual, Monitored parameters Alarming parameters Potheads GAMMA (G), G-trend (GTr), G-temperature dependency (GT) G, GTr, GT GAMMA range 0 16 % Power frequency at the monitored object 50, 60 Hz Gamma resolution 0.1 % Gamma Phase resolution Built-in diagnostics Bushing Tan and capacitance Self-Test and Self-Calibration Transformer Rated voltage (order proper bushing sensors correspondingly to bushing rated voltage and capacitor/potential tap design) At loading and before every measurement kV

9 Page 9 Effective: May 2007 BushingGard TM Installation and Operation Manual, Display, Keypad and External connections 1. Bushing Sensor Phase A1 7. Display 6. LEDs Alarm Warning Status 8. Three Load Current Inputs 2. PD port Phase A 9. Humidity Input Phase B1 10. Three Temperature Inputs Phase C1 Phase A2 11. USB Port Phase B2 Phase C2 12. RS Status 4. Warning 13. AC/DC Power 5. Alarm Figure 1 External connections are presented in the Table External Connections.

10 Page 10 Effective: May 2007 BushingGard TM Installation and Operation Manual, Table External Connections Connection Name Index Fig.1 Number of connections Wire Type Bushing Sensor 1 6 RG-58/U, AWG20, OD PD ports 2 6 BNC connectors for an external PD device C-form dry relay contacts. Status, Warning, Alarm 3, 4, 5 3 Twisted pair AWG14-30 Load current wire cable (shielded, noneshielded) AWG18-30 Humidity input wire cable (shielded, noneshielded) AWG18-30 Temperature input wire cable (shielded, noneshielded) AWG18-30 USB (type B) interface 11 1 USB cable Isolated RS-485 interface 12 1 Twisted pair. AWG Power source 13 1 G-N-L power cable AWG14-22 (10 A, VAC)**or Shielded twisted pair (AWG for VDC The display is a bright graphic unit. The BushingGard displays information during setup and memory modes of operation. During normal operation it can be programmed to continuously scroll results of the most recent tests. It also displays all error messages. The keypad has four navigation arrows and four functional keys to facilitate options. (Use the enclosed insulated pin on keypad to avoid keypad knob damage!) The monitor has three LEDs that display Status Green, Warning Yellow and Alarm Red. The Status LED has three modes of operation: 1 Lit continuously Normal 2 Flashes every three seconds Measurement (device will not respond to communications, but answering Busy ). 3 Flashes once a second device or signal Error Alarms BushingGard has two independently configurable alarms Red and Yellow. (The alarms are also independent for both sets.) Three parameters can cause an alarm: Gamma-parameter magnitude, Temperature coefficient of Gamma and Gamma trend. Yellow and Red alarms operate differently. In the case of a Red alarm condition, BushingGard

11 Page 11 Effective: May 2007 BushingGard TM Installation and Operation Manual, will first initiate an additional measurement in five minutes and, if alarm condition is confirmed, will activate the alarm relay and turn on Red LED. If the Red alarm condition is not confirmed by additional test, the status of the alarm will be as per this additional measurement. If after any measurement a parameter has dropped below alarm threshold BushingGard will indicate the reduced alarm status by turning off the associated LED and changing relay contacts status. Alarm relay has a hysteresis to exclude a relay bouncing at parameter values changing slightly near alarm threshold. The Alarm relay can operate in two modes (configurable): it can be set to latch in alarm status until the alarm status disappears. Or it can be latched for a limited configurable time. At the next measurement, if the alarm status is detected, the relay will be kept latched in alarm status for the same time. Ranges of available alarm settings and recommended default values are presented in the following Table Table Alarm setting Alarm Parameter Range of setting available Default setting Gamma magnitude-yellow (Warning) Level 0 to Red level 2% Gamma Magnitude- Red (Alarm) Level 0 to 12.5% 4% Gamma trend (normalized to 1 year)- Red (Alarm) level Gamma vs. Temperature (normalized per 0 C)- Red (Alarm) level Trend calculation 0 51%/year 10% per year %/ 0 C 0.1% per 0 C BushingGard calculates GT - the trend of the Gamma-parameter in terms of Gamma change per year (%/year). Trend is calculated as a linear approximation of data over a specified time interval and has only one alarm threshold - Red Gamma-versus- Temperature Coefficient calculation BushingGard calculates GTr - temperature dependency of the Gamma-parameter It is calculated as a linear approximation of data over a specified time interval in terms of Gamma change per degree Celsius (%/ o C). Temperature dependence has only one alarm threshold - Red Continuous Watch Feature Between scheduled measurements the Continuous Watch is armed. The device checks for Gamma level every five minutes. If Red alarm level is detected, BushingGard initiates a full measurement and, if the Red alarm is confirmed, device indicates it.

12 Page 12 Effective: May 2007 BushingGard TM Installation and Operation Manual, Schedule The measurement can be performed on a prescribed time of a day or on a fixed time interval basis (configurable). The device is shipped with Time basis schedule enabled and set for eight measurements per day. This is sufficient for all common applications. If necessary, device can be set to measure up to 8 times per day at scheduled times or in specific time interval varying from 1 minute to 11 hours 59 minutes Device Address BushingGard supports addressing and can be networked to any local network supporting MODBUS RTU protocol. As default, BushingGard is shipped with the device address #1. The address of each device must be unique in each particular local device network Self-test and Self-calibration When powered up and before each PD measurement, BushingGard performs a self-test and calibration and check for a presence of signals. In case of any fault, the device displays appropriate error message and opens NO relay contacts of Status relay Auxiliary Input BushingGard has three temperature inputs configured for 100-Ohm RTD, one humidity input and three AC inputs for load current. The fourth AC input is reserved for the future purposes Measurement Suspend Monitoring can be suspended in two different ways. Monitoring can be stopped manually at any time. The operator is responsible to start it again. Monitoring can be paused. In this case, monitoring will resume automatically in three hours Software BushingGard is shipped with database software supporting: Communication to device from PC or local RS-485 network or phone modem. Data downloading and storage for multiple devices. Data analysis and presentation. Separate utility is supplied for the device setup from PC.

13 Page 13 Effective: May 2007 BushingGard TM Installation and Operation Manual, 2.1 Application Issues 2 Installation With appropriate choice of bushing sensors BushingGard could be used on kv power transformers and current transformers. Generally, the following technical issues are considered prior to device installation: Type and specifics of the equipment to monitor. Rated voltage and bushing capacitance. Type/design of bushing test taps. Noise and grounding aspects Device location and environmental issues. Networking and Communicating to the device Type and specific of equipment to monitor. BushingGard was designed to monitor bushing capacitive currents within the range of 1 to 120 ma rms. The expected value of the current can be determined preliminarily using the formula: U[ kvrated] 6 I = * 2* π * F[ Hz]* C1[ pf]* 10, ma rms, 3 U is the operating voltage of the bushing (L-L) in kv, F is a power frequency (60 Hz, 50 Hz), C 1 is the capacitance shown on bushing nameplate in pf. Note: every EEPD bushing sensor of TBS-2 series has an upper limit of this current that has not to be exceeded. If in your specific case the upper limit for the sensor should be increased you need specify this at the time of order. If the calculated current is below 2mA the application range can be extended by changing device input impedance. For that, please, contact Eaton Electrical representative or directly EEPD. The connection to bushing test tap varies significantly from equipment to equipment and from manufacturer to manufacturer. Different countries also have very different standards of connection design. EEPD is producing now several modifications of bushing sensor that applicable to the majority of bushings in North and South Americas. There is still some variety left, especially in European and Asian countries. If your equipment has taps not covered with produced now sensors, please consult with Eaton Electrical representative or EEPD directly on available options and solutions Noise and grounding aspects. Gamma parameter involves measurements of as low as 1 ma current with the accuracy of

14 Page 14 Effective: May 2007 BushingGard TM Installation and Operation Manual, 0.1%. Such signals may be accompanied by a wide variety of noises at different frequencies. For example, on DC/AC converter substations the current through the tap produced by higher frequencies (from Hz to khz) can reach several amperes. BushingGard filters out all high frequency noise. Unfortunately, power frequency noise, produced by potential difference on the grounding cannot be filtered out, but proper grounding practice almost always resolves the problem. The sheath of each coaxial cable is grounded on the sensor body that is electrically connected to a transformer tank. Signals from bushing sensors are brought to the device, and sheaths stays ungrounded here. The measuring circuit is connected between the central wire of each cable and local ground (inside the enclosure). If there is some difference in ground potentials on the tank and on the enclosure it will be divided between the sensor and the measuring device proportionally to their input impedance. The sensor impedance (about 2.5 kohm) is much higher than of measuring input of the device ( Ohm), so only a small part of the noise will appear on the device input. This part will be additionally reduced if the difference of potentials on the groundings of the transformer and of the enclosure is lowered as possible. Positioning of the enclosure closer to transformer and grounding it to the transformer tank is recommended! In the case of a three-phase transformer in a single tank, a solution is to place the enclosure just at the transformer tank. In the bank of three single-phase transformers or a set of current transformers placing the enclosure at middle phase is preferential. If this is not enough additional measures to bring transformer s tanks to approximately the same potential can be taken by connecting tanks with a low impedance conductor Device location and environmental issues. BushingGard can be delivered in two options: with and without environmental enclosure. Without an enclosure it must be placed inside a control cabinet at a transformer. Good grounding circuit to transformer tank should be provided. In most practical applications, BushingGard is supplied in a NEMA-4X enclosure protecting the device from direct rain, sun and dust. Planning a location for the BushingGard device, consider a non-vibrating location, close to the transformer and conveniently located relatively to all sensors as well as to intended communicating means (phone jack, tray to control room for alarms and so on). In the case of three single transformer groups, the middle tank is the most preferable option Networking and Communicating to the device. BushingGard provides several interfaces for alarms, SCADA and data re-transmission. Always wire up alarm relay to an annunciation system!!. RS-485 interface with database software allows remote device setting, measurement initiation, and data downloading. If you will request from time to time an expert opinion consider designating a permanent or available on request phone line and specify a modem when ordering. You can network up to 231 BushingGard (for RS-485) to the same modem.

15 Page 15 Effective: May 2007 BushingGard TM Installation and Operation Manual, Cellular modem subscription option is also available BushingGard Set contents BushingGard set includes: 1. BushingGard device 1pc. 2. NEMA-4X enclosure with installed inside: Mounting panel 1 115V receptacle (230V option - no receptacle) 1 DIN-rail terminal strip for external connections hub 2 Misc. mounting hardware For areas with ambient temperatures below 40 0 C only- a heater with temperature switch and thermal insulation on all walls and door 3. RTD (100 Ohm Pt) hot-oil temperature sensor with 65-ft cable and installation kit (thermal insulation tape and foil sheet) 4. Load sensor (aux. 5Amps Current sensor) 1 5. Humidity sensor (normally installed in the enclosure) 1 1 set 1 set 6. Bushing sensor TBS-2- with 65- ft coax cable 3 (6 Optional) (the model of sensor is determined by bushing rated voltage and the design of bushing tap. Please, discuss that matter with EEPD prior to ordering or fill out a respective Questionnaire; also confirm the required cable length) 5. Landline or cellular modem 1 (Optional) 6. RS485/RS232 converter 1 (Optional) Not included in the standard set are: 1. Cables for interfaces. We recommend for interfaces the following tray cables 1-pair shielded control cable from the Catalog of Allied Electronics, 2001, page 309, Stock # (22AWG) BELDEN Mfr #9322 Stock # (20AWG), BELDEN Mfr #9320, (Preferable for communications over 1000ft) Stock # (20AWG)), by BELDEN Mfr #1033A. 2. Power cable 120VAC (or 240VAC), 10 A, L-N-G AWG OD should not exceed Cable conduits (flexible or pipes) for incoming and outgoing cables.

16 Page 16 Effective: May 2007 BushingGard TM Installation and Operation Manual, BushingGard connection diagram The basic diagram of BushingGard is presented on Figure 2. All connections on site are brought to the terminal blocks mount on DIN rail. The BushingGard in NEMA 4X enclosure is shown on the Figure 3. The modem is optional. If no modem has been ordered, the associated components will not be installed. Optically isolated RS-485 interface is assigned for communication to a device through a local network or directly to a computer through RS-485/RS-232 or RS-485/Usb converter. If a modem installed, RS-485 interface is brought to the modem too. Only one modem is required for several devices connected to one RS-485 network. Detailed connection circuit description is in the table Connections below.

17 ` Instruction Manual Page 17 Effective: May 2007 BushingGard TM Installation and Operation Manual, BushingGard Wiring Diagram WD-1 DIN-Rail Terminal Strip A1-SIG 1 A1-SH 2 B1-SIG 3 B1-SH 4 C1-SIG 5 C1-SH 6 A2-SIG 7 A2-SH 8 B2-SIG 9 B2-SH 10 C2-SIG 11 C2-SH 12 RTD-COM 13 RTD-COM 14 RTD-SIG 15 LOAD-GND 16 LOAD-SIG 17 STATUS-NC 18 TB-1 TB-2 TB-3 TB-4 TB-5 TB-6 TB-7 TB-8 Sample!!! 100 Ohm TB-9 TB-10 STATUS-COM 19 STATUS-NO Actual 20 Schematic TB-11 in WARNING-NC 21 TB-12 BLK WARNING-COM 22 RED WARNING-NO 23 H% SENSOR ALARM-NC 24 G3 Enclosure ALARM-COM 25 ALARM-NO 26 A(+) RS B(-) RS LINE N GR L NEUTRAL GROUND ENCLOSURE, PANEL GROUND TB-18 TB-19 TB-20 TB-21 TB-22 TB-23 TB-24 TB-25 TB-26 Sh Sh Sh Sh Sh Sh NC C NO NC C NO NC C NO Input PD Input PD Input PD Ph-A1 Ph-B1 Ph-C1 Ph-A2 Ph-B2 Ph-C2 Input PD Input PD Input PD Ref Status Warning Alarm RTD1 H% In4 In3 In2 In1 RTD2 RTD3 USB CAN-Int RS-485 G Out Heater/T 115 / 230 VAC 5 C C C C C C U B A L NC C NO N TB-17 TB-16 RED SH BLK TB-15 TB-14 TB-13 TB-29 TB-32 TB-34 Figure 2 Wiring Diagram.

18 Page 18 Effective: May 2007 BushingGard TM Installation and Operation Manual, Connections Pin## Circuit name Note 1&2 Input from bushing sensor A1 signal (1)&shield (2) Shipped shortened! 3&4 Input from bushing sensor B1 signal (3)&shield (4) Shipped shortened! 5&6 Input from bushing sensor C1 signal(5)&shield(6) Shipped shortened! 7&8 Input from bushing sensor A2 signal(7)&shield(8) Shipped shortened! 9&10 Input from bushing sensor B2 signal(9)&shield(10) Shipped shortened! 11&12 Input from bushing sensor C2 signal(11)&shield(12) Shipped shortened! 13&14&15 Input for 100 Ohms RTD, 13&14 common, 15 - signal 16&17 Load current input 18&19&20 21&22&23 24&25&26 19 common (black), 20 signal (red) STATUS dry relay contacts. 21 NO 22 Common 23 - NC WARNING dry relay contacts. 24 NO 25 Common 26 - NC ALARM dry relay contacts. 27 NO 28 Common 29 - NC 27&28 SPARE 29&30&31 LINE VOLTAGE OF 120/240 VAC POWER CABLE. 32&33 NEUTRAL WIRE OF 120/240 VAC POWER CABLE. 34&35 GROUND WIRE OF 120/240 VAC POWER CABLE. Coax Cable RG-58 Coax Cable RG-58 Coax Cable RG-58 Coax Cable RG-58 Coax Cable RG-58 Coax Cable RG-58 Three wire cable, AWG Twisted pair, 18-30AWG 12-14AWG 12-14AWG 12-14AWG USE 32 FOR LINE POWER CONNECTION USE 34 FOR NEUTRAL CONNECTION USE 36 FOR GROUND CONNECTION

19 Page 19 Effective: May 2007 BushingGard TM Installation and Operation Manual, Industrial grade RS- 485 Modem. Optional! Bushing sensor connection points. Shipped shortened! Remove jumpers at start up! Local Ground Connection! Figure 3.

20 Page 20 Effective: May 2007 BushingGard TM Installation and Operation Manual, 2.2 Installation ATTENTION: RELEVANT NATIONAL AND LOCAL SAFE WORKING PRACTICES PERTAINING TO WORK ON HIGH- AND MEDIUM- VOLTAGE EQUIPMENT MUST BE OBSERVED WHEN PERFORMING THE INSTALLATION AND STARTUP DESCRIBED IN THIS DOCUMENT Important Safety Notes This Manual is designed for qualified personnel involved in the on-site installation of TBS bushing sensors and commissioning of transformer insulation monitoring or measuring systems. All installations and connections must be done on de-energized transformer, properly grounded and isolated from hazardous energy sources. Bushing sensor output coaxial cable must be properly terminated or shortened while a transformer is energized. Leaving sensor output un-terminated may introduce hazardous voltage to up to 140VAC on its output. This also causes sensor protection circuitry to operate and should be considered as abnormal sensor operation. If the monitor is shipped assembled on back panel (or in enclosure) coaxial cable inputs are shortened on DIN rail terminal blocks. The shorting jumpers must be removed at commissioning after checking all circuits. Keep shorting jumpers for possible reuse, if the monitor will be disconnected in the future BushingGard Installation The monitor can be shipped in two options: mount on back panel or in NEMA-4X (IP-66) enclosure. In all cases locate the device as close to a monitored transformer as possible. Transformer tank is most preferred option. The monitor location should not have excessive vibrations. Back Panel dimensions are12.2 x12.2. It has four mounting holes 0.27 in diameter with the centers at x Mount back panel in appropriate control cabinet providing for weather and direct sun protection. NEMA-4X enclosure dimensions are x14.18 x6.7. It can be wall mount in two ways: o Using four through-holes in the enclosure with the centers at 13.2 x13.2. This requires FILISTER HEAD ¼ screws with the length of, at least, one inch. o Using four holes 0.27 in diameter in the corner brackets with the centers at 14.2 x14.2.

21 Page 21 Effective: May 2007 BushingGard TM Installation and Operation Manual, Install the enclosure. Install back panel with the monitor mount inside the enclosure or the control cabinet Properly ground the back panel using the designated bolt. Note that grounding point MUST be connected to transformer tank in the shortest possible way with the wire of, at least, 12AWG. This link will provide a return path for AC currents from bushing test taps. Check that resistance between panel ground and a transformer tank is below 0.3 Ohms! As the outage of the transformer could be limited in time we recommend installing the BushingGard enclosure prior to transformer outage, so cables from sensors are connected to proper terminals immediately after sensor installation. Run conduits for signal cables, cables to enunciation system, SCADA and to the power supply. Note that Electrical Code requires separate conduits for power and signal wires. Prior to terminating have the excess of cable lengths in the enclosure up to 2. Label all cables. Connect alarm relays to enunciator. The simplest way is to connect NC contacts of alarm and warning relays and NO contacts of the Status 1 relay in series and run one line for annunciation purpose. Connect power cord according to included with shipment wiring diagram. Make sure that power source breaker is opened and properly isolated or power source is OFF before making a connection. Do not supply power until all circuits are assembled and tested Bushing, Temperature and Load sensors. Install sensors in strict accordance with Installation Manuals for particular sensor that is included in the delivered set. This job can be performed on switched off and grounded transformer only. Be sure all requirements on safety installation are met, and the personnel qualified to work on high voltage electrical equipment execute jobs. The bushing sensors are installed on capacitor/test taps of bushings. The temperature sensor is installed on a pipe carrying hot oil out of the transformer tank for cooling as close to the tank as possible, being then thermally insulated from ambient air and covered with reflective aluminum foil. The current sensor should be placed onto the secondary winding of a transformer load current transformer. Note that CT sensor may be placed in any five Amps circuit representing transformer current. The sensor will be calibrated at a commissioning to represent a percent of load. Provide conduits or pipes for mechanical protection of cables between sensors and the BushingGard enclosure (or control cabinet) if required by local standards and run the 1 The device after powering up and successful passing self-tests will open its NC contacts of the Status relay indicating NORMAL device condition. At a device malfunction or power supply loss NO contacts will be opened again indicating a problem.

22 Page 22 Effective: May 2007 BushingGard TM Installation and Operation Manual, cables inside the conduits/pipes. If cables from bushing sensors have excessive lengths you may cut them. If possible cut cables from bushing and neutral sensors by identical length (to ensure that simultaneously appeared impulses reach the BNC connectors of the device simultaneously). You may neglect this recommendation if difference in the lengths is very large, as it could be in three-phase banks of single-phase transformers, especially of kv. Coil the excessive lengths leaving about 2-4 for convenient terminating. Label all the cables. Prior to connection of bushing sensors to the device, check with Ohm-meter that central wire and shield of coax cable are open circuit and the shield to ground resistance is below 1 Ohm (do not exceed 50 V test voltage). Check the capacitance of the sensor ensuring proper sensor connection. The capacitance should be close to 1 or 2 microfarad if other is not specified. Connect coaxial cables from bushing sensors to corresponding terminals on DIN rail terminal block. The first six terminals are assigned to one set of bushing sensors (HV side, for example) and the following six terminals for the second set (MV or LV side). The sequence of connection should be the phase A the first, the phase B the second and the phase C the third. The connection assumes A-B-C phase rotation. If a rotation is different from A-B-C make connections to ensure the described rotation. Normally, this means swapping B and C phases. Recommended coaxial cable preparation steps are: remove 0.95 of PVC jacket (black), separate shield from center conductor insulation to full length, equalize the length of shield and center conductor, remove center conductor insulation for Remove shortening jumpers from bushing sensor input terminals and save them for the future reuse. Check with a multi-meter the ~100 Ohms (40 Ohms for 800kV system) resistance between coaxial cable central conductor and shield. This resistance represents input impedance of the monitor. Having an open circuit at this stage is inappropriate! Troubleshoot a circuit, if measured resistance differs from expected value before proceeding to next step! Connect RTD and CT sensors according to included wiring diagram. Check with a multimeter: about 110 Ohms resistance between red and black wires and several Ohms between black and white wires of RTD sensor 40 Ohms between red and black wires if CT sensor Powering up the monitor and energizing transformer. Open the fuse circuit in the DIN rail terminal block by pulling up the fuse holder. Close power breaker. Check with a Voltmeter that appropriate (120/230) volts are present across line and neutral and ground terminals.

23 Page 23 Effective: May 2007 BushingGard TM Installation and Operation Manual, Close the fuse circuit by pushing down fuse holder. The device will perform a calibration, self-test and signal check (indicated by Loading on the display). In case of any abnormality, the status LED will start flashing about twice a second and appropriate Error message appears (Likely Unt OFF, since transformer is not energized). If transformer is energized another common error message will be: Phase set 1(2) indicating wrong phase rotation on the set 1 or the set 2. This message will require swapping B and C phases and rebooting the monitor to check that the message has disappeared. Check for a reasonable temperature reading on the display, while transformer is offline. You will have an opportunity to fix a problem, if any. The display for the temperature reading looks the following way: The circled number should reasonably represent top oil temperature. Energize the transformer and warm it up to normal operating temperature. Warming up a transformer is important before initial balancing the monitor. Check that bushing signals are within appropriate and expected range. Measure a voltage U on each signal input to the ground (use an AC voltmeter). Remember that coaxial cable shield terminal may not be at the local ground potential. Calculate signal currents I=U/R input. R input input resistance usually 100 Ohms (40 Ohms for bushing currents >60mA). Refer to the device documentation for exact input impedance. Refer to bushing current estimates described earlier in this manual. The system now is ready for startup and final commissioning.

24 Page 24 Effective: May 2007 BushingGard TM Installation and Operation Manual, 3.1 General 3 Startup BushingGard allows for device setting from keypad or via RS-485 or USB interface from PC using setting utility. Have BushingGard software installed on your PC before proceeding. (Setting from PC is more convenient. For software setting please read also Configuration Utility MANUAL.) Device is installed, all signals are connected and tested and system is powered up. Transformer is energized and warmed up to its normal operating temperature. Setting up the device at normal operating temperature and load is recommended. If the device is balanced at much lower or higher temperature than normal data may have an additive that reflects temperature dependency. Make sure that you have ready Off Line test bushing data (Power factor and capacitance for each bushing) and 3.5 digit (or better) battery powered AC voltmeter. Find the monitor MODBUS address and baud rate setting from the affixed to the device temporal label. In case this information is missing, refer to Keypad settings in Appendix 1 and retrieve the required information from a device! Note 1. The procedure below describes most time efficient software setting procedure. For full keypad setting description refer to the Appendix 1. Note 2. At startup ERROR messages may occur reflecting likely wrong signals or connections. Refer to Appendix 2 for error meaning. BushingGard allows for device setting from keypad or via RS-485 or USB interface from PC using setting utility. Have BushingGard software installed on your PC before proceeding. (Setting from PC is more convenient. For software setting please read also Configuration Utility MANUAL.) 3.2 Step 1 Establishing communication to the monitor. Get BushingGard software installed on your laptop PC. Connect PC to the monitor using provided USB cable or using a converter to RS-485 monitor interface. In case of USB connection, the first read Setting Utility Manual and install accordingly USB driver. USB connection should be done with provided USB cable or another standard USB cable with type A and B connectors. In case of RS-485 converter, use two wire schematic connecting (A and B or + and - terminals of the converter to the correspondent terminals of the monitor RS-485 interface located at the right bottom part of the top device module. Follow the monitor label for connections.

25 Page 25 Effective: May 2007 BushingGard TM Installation and Operation Manual, Start Setting Utility software. In case of USB connection you need to set only the correct MOBDUS address. In case of use of any RS-323 or USB to RS-485 converter, you need to set correct all: MODBUS address, PC comport and baud rate in the software communication settings. Request Date and Time from the monitor and set the correct values. In case of communication error you need to find the correct communication settings of the device, communication settings of PC and check connections. Request number of records in the device memory by Get measurement count. The count under Measurements- should display zero. This is the way all devices are programmed in the factory. If the number is not zero, type in ASCII protocol window the message: clear ; exactly as shown and press ENTER. Check again number of records in 30 seconds. It must be zero. 3.3 Step 2 Setting the Monitor It is assumed that communications have been properly established. Request the device settings Common Settings Tab

26 Page 26 Effective: May 2007 BushingGard TM Installation and Operation Manual, The settings that must be checked or may be changed during startup are highlighted. Changing communication settings. You may change the device address and communication baud rate at this dialog, if planned to do so, make changes and press Send Settings button. Do not make any other changes since they may not take an effect. Right after a change has been sent to the device you will need to adjust accordingly the communication settings in Main Dialog and then request settings again to continue with any other changes. Alarm Relay. We recommend to wire alarm contacts to your enunciation system and have the setting in ON or for time status. Calc Load on Current Channel. Normally, the load current signal is always connected to the first current channel. Make sure that is set for #1. Stop Monitoring. MUST be unchecked. Measurement Schedule. Normally, set for Schedule with eight measurements a day as shown. Note that all unused time settings after the used ones MUST be zeros. When done with common settings proceed to the following tabs Set1 (2) Tab

27 Page 27 Effective: May 2007 BushingGard TM Installation and Operation Manual, The settings that must be checked or may be changed during startup are highlighted. Unchecked settings should be as shown in the picture. Settings for the set 2 are similar with the set 1. Follow these recommendations for the set 2, if in use. Enabled for Monitoring. At least, one of sets MUST be enabled. If only one set of bushings is monitored, use set 1 and disable the set 2. Rated parameters. Enter the correct Voltage and current ratings for the monitored transformer. Rated voltage assumes phase-to-phase voltage. Off Line Data. You have to enter off line data for C1 capacitances and Tan Delta and temperature of the test for each bushing. We always recommend using most recent test data. If is not available, use nameplate data. Temperature channel. Hot oil temperature sensor, as default, is connected to the first temperature input. Check that this correct and, if different, adjust accordingly. Input Impedance. This setting is programmed in the factory. You should have correct numbers in the monitor and do not need to change them. In some occasions, if test tap current is too high and you are getting Error message indicating high signal magnitude, you may connect in parallel with the monitor input an external resistor. In such a case, you must precisely measure new resistance (0.1% accuracy) and enter the correct number. Repeat the same procedures for the second set, if enabled, or disable it, if unused. When done proceed to Auxiliary Inputs tab Auxiliary Inputs Tab The settings that must be checked or may be changed during startup are highlighted. Unchecked settings should be left untouched. Read From Registers. Normally, this control MUST be left unchecked. In only case of OEM type applications, while the monitor is a part of another monitoring system and a MASTER controller supplies required auxiliary information over RS-485 interface, this control is checked. In OEM applications any external sensors, except of bushing sensors, are not necessary. Temperature 1. The first temperature channel is used for hot oil temperature measurements. Verify that calibration numbers are as shown. Current 1. The first current channel is used for load current measurements. Offset should be left zero, if the supplied sensor is used. Slope value should be adjusted to display a correct percent of the current load. Connection must reflect a phase of a placement of the current sensor.

28 Page 28 Effective: May 2007 BushingGard TM Installation and Operation Manual, Humidity. Check that calibration numbers are as shown, if Eaton humidity sensor is connected. When done, press Send Settings button. New settings are sent to the monitor. 3.4 Step 3 Balancing the Monitor Select Balance option from main command menu and press Start. The monitor will perform calibration and self-test, auto-balancing and will measure initial data. This takes from 3 to 7 minutes. Different messages will be displayed as balancing is in progress. When finished, the device will enter monitoring mode and will start scrolling the information that is assigned for displaying. Request settings from the monitor and verify that good balance is achieved using Balancing Data button. Imbalance Current [%] should be 0.1 or better. Repeat balancing, if necessary. Note, that in locations with HIGH harmonics a good balance may not be achieved. This is typical for AC-DC substations on DC side. You may be satisfied with Imbalance to up to 0.3%,

29 Page 29 Effective: May 2007 BushingGard TM Installation and Operation Manual, if several attempts do not provide for a desired value. In a case of high imbalance current double-check for proper ground and bushing signal connections! As all signals are now being tested, you may receive an Error message, if one or more of tests have not passed. The full description of error messages and their meaning is the Appendix Step 4 Taking Several Readings The final step is in taking several readings and verifying that data received is reasonable and acceptable. Select Single from command options in main command menu and press Start button. This will trigger a measurement. Repeat 5-7 times and download new data into BushingGard data base software. Check that data is reasonable.

30 Page 30 Effective: May 2007 BushingGard TM Installation and Operation Manual, 4 Appendix1. Device Setup via Keypad 4.1 Keypad Device has eight-pushbutton keypad. The buttons should be pressed gently using about 0.1 preferably plastic sticks. Keys functionality as follows: «Esc» -used for canceling command and returning to previous or higher-level submenu; (arrows) used for a change values and change menu options; «Ent» - used to select menu option or start a procedure and to confirm value change; «Mem» - used to enter in memory mode for archived data observation; «Mod» - used to enter into manual setup mode. 4.2 Setup via Keypad Key «Mod» should be pressed to enter setup mode. Prompt for password should appear on the display as shown: Enter password 5421 using arrows moving from numeral to numeral and confirm pressing «Ent». Wait for about 20 seconds after entering password. If waiting more than 30 seconds and setup mode is not displayed, press «Esc» and repeat. Attention! The password is coded into device memory and cannot be changed. Setup mode will be indication by flashing LED «Status» and displaying current date. Scroll setup options by keys and select an option by pressing "Ent". Exit setup mode by pressing «Esc». All changes will be saved in setup memory.

31 Page 31 Effective: May 2007 BushingGard TM Installation and Operation Manual, Setting Date Date format is DD/MM/YY. Press «Ent» date setup. The current symbol is underlined. Use to select another symbol or «to change its value. When finished, press «Ent» to confirm or «Esc» - to exit without a change Setting Time Time format is military HH:MM:SS. Its setup is similar to date setup Setting MODBUS Unique Address. The monitor allows for setting up to 255 addresses. Note that RS-485 standard limits number of devices per single network branch with 32. This limitation comes from loading capability of RS-485 driver. Appropriate repeater (power amplifier) should be used, if more than 32 devices are planned on network. Press «Ent» and the following display will show the current device address. The current symbol is underlined. Use to select another symbol or «to change its value. When finished, press «Ent» to confirm or «Esc» - to exit without a change Setting Communication Rate Press «Ent» and the following display will show the current baud rate.

32 Page 32 Effective: May 2007 BushingGard TM Installation and Operation Manual, Using select desirable rate (9600, ) Communication Protocol Press «Ent» and the following display will show the current protocol. Using select desirable protocol («Modbus RTU» «Modbus TCP»). Attention, Eaton s software uses Modbus RTU protocols! Modbus TCP is developed for customer software development where is needed Activating Sets for Monitoring Press «Ent» and the following display will show the current status ON/OFF of the Set1 (Inputs A1, B1 and C1). Use to change set activity status or «to scroll between sets Initial Balancing Signal Overview Initial balancing procedure should be performed once at comissioning time. This procedure sets Imbalance current in summation circuitry close to zero by adjusting digital potentiometers. Adjastment range is 20%. Change of input impedances is require to account for larger differences.