Electrotechnical production

Electrical devices setup workshop services:

· starting-up, adjusting, testing and operational tuning of basic and auxiliary electrical equipment;

· troubleshooting procedures for basic and auxiliary electrical equipment and grounding equipment;

· design works for construction and modification of power engineering plants and installations;

· evaluation of construction and modernization projects in power engineering, including power plants under construction or in operation;

· preparation of operation instructions and manuals for basic and auxiliary electrical equipment;

· design and installation of relay protection and automatic operation systems, fault detection and alarm systems for electrical equipment, customized protection and automatic operation systems;

· repair and verification of electrical and thermal tools of measurement, non-destructive testing, gas analysis;

Electrical devices setup workshop products

AUTOMATIC DEVICE FOR INSULATION COMPLEX ADMITTANCE MONITORING IN 330 KV CURRENT TRANSFORMERS UNDER OPERATING VOLTAGE (KITT 30)

This device provides automatic monitoring of variation of a sum of insulation admittance currents in three phases of a current transformer, previously balanced to minimum, in each connection. The device is used as a part of an automatic operation control system in a power installation.

Specifications

Insulation complex conductance measurement range	0,1 – 4%
Suppression third harmonic and higher harmonics	40
No. of monitored 330 kV current transformers	24
Interface	RS232

KIT FOR BASIC INSULATION MONITORING IN 330 KV CURRENT TRANSFORMERS UNDER OPERATING VOLTAGE

Measured variables:

1. dielectric loss (tg d) of a current transformer insulation in a monitored connection, relative to a current transformer in a reference connection;

2. complex admittance (sum of basic insulation leakage currents in three phases), using a selective voltmeter.

Kit components:

· stationary sensors mounted between the measuring terminal and the current transformer case;

· connection cabinets, mounted on the supports of “B” phases in the connection;

· portable measuring circuit, including two cable drums with a shielded cable;

· connection unit and measuring bridge (P5026);

· selective voltmeter.

COMPLEX ADMITTANCE INDICATOR FOR INSULATION MONITORING IN 330 KV CURRENT TRANSFORMERS (“IPRIZ”)

The indicator provides periodic monitoring of an insulation condition in 330 kV current transformers under operating voltage.

The variable controlled is a variation of complex admittance of insulation, providing detection of insulation defects on early stages of their emergence.

AUTOMATED AC SWITCHBOARD

The switchboard provides uninterruptable power supply (380/220 VAC, 50 Hz) for critical power consumers, such as control rooms, communication centers etc.

Functions:

· connection of two independent feeders from external power sources and one more feeder from standby diesel power plant;

· automatic start of standby power plant, if there is no voltage on the common feeders;

· manual load switching between the feeders;

· distribution of electric power by load;

· power metering on each feeder.

Specifications

Rated current	400 A
Rated voltage	380/220 V
Weight	£ 170 kg

DC SWITCHBOARD FOR POWER PLANTS AND SUBSTATIONS (110 – 750 KV)

The switchboard is used for distribution of DC control current from an accumulator battery.

Switchboard components:

· lead-in cabinet;

· lead-out connection cabinets (two or more);

· control cabinet.

The switchboard is equipped with:

· automatic switches (A3715, VA2129, VA5735 etc.);

· measuring circuit devices;

· switches and circuit breakers (according to the wiring diagram).

The control cabinet includes:

· voltage level control unit (BKN) for voltage monitoring on the DC control current buses;

· data acquisition unit (USD) with local alarm unit (BMS);

· “Sapfir-4”, a system for automated searching for ground faults in the DC control current circuit;

· selective unit for insulation monitoring (UKI-SM);

· circuit for indication of position and condition of the switchboard components;

· measuring circuit.

Control cabinet dimensions: 600 x 600 x 2000 mm.

MICROPROCESSOR-CONTROLLED RECTIFYING UNIT (UVM)

The microprocessor-controlled rectifying unit (UVM) is a thyristor-based charging and recharging device with a thyristor bridge controlled by a microprocessor unit. The rectifying unit can be used as a part of the DC control current power supply systems in power plants, district boiler plants and substations, equipped with stationary accumulator batteries.

Depending on the power system, in which the rectifying unit is used, the unit can operate with the DC control current load buses, in parallel with the accumulator battery, or directly, with the accumulator battery turned off.

Specifications

Power	380 V+10%, -5%; 50±1 Hz
No. of phases	3
Rated output current, Irated	100 A (20 – 100 A)
Rated output voltage, Urated	260 V
Battery charging IU characteristic (DIN)	41773
Output voltage stabilization accuracy, % Uoutput	£ 1
Output voltage adjustment range, % Urated	0 – 100
Output voltage ripple during operation with an active load, %	£ 5
Output voltage ripple during operation with an accumulator battery, %	£ 1
Overload protection operating current	125 A
Output voltage correction range depending on temperature, mV/°C	0 – 5

CONTROL CURRENT CABINET

The control current cabinet provides power supply for DC control current circuits in control, protection, automation and alarm systems.

Specifications

· Power: 220 V AC, mains frequency.

· Rated output voltage: from 200 (110) V DC.

· Charger rated output current: 10 A (each charger).

· No. of accumulators: 17 units (34).

Dimensions

· Control current cabinet: 2100 x 800 x 800 mm.

· Accumulator battery cabinet: 2100 x 600 x 800 (2100 x 800 x 800) mm.

· Control current cabinet weight: 100 kg max.

Control current cabinet components:

· voltage level monitoring relay (KSV);

· voltage availability monitoring relay (KLV);

· chargers (2), 220 V / 10 A (UZ1, UZ2);

· voltage monitoring relays (2, on UZ1 and UZ2);

· accumulator battery charge/discharge current monitoring ammeter (RA1);

· insulation monitoring circuit;

· microprocessor-controlled DC protection devices (2) (ZPT-001);

· monitoring unit for DC protection devices;

· heating circuit (including a temperature sensor, a contactor and resistors);

· “Sapfir-4” unit (upon the customer’s request);

· flashing light relay (upon the customer’s request).

AUTOMATIC VOLTAGE CONTROL PANEL FOR DC BUSES (“PDE-9045-B”)

The “PDE-9045-B” panel, a new device intended to replace outdated “PEH” devices, provides automatic maintenance of voltage on DC switchboard buses (ARN-2) and recharging of terminal elements in accumulator batteries (ARN-3).

Specifications

DC mains rated voltage	220 V
Power supply rated voltage	220 – 240 V, 50 Hz
Power consumption from AC mains	350 VA
Voltage level setting range (ARN-2)	190…260 V
Voltage setting range (ARN-3)	7…75 V
Maximum permissible current (ARN-3)	4 A
Voltage control accuracy (ARN-3)	£ 1%
Dimensions	1600 x 600 x 500 mm
Weight	90 kg

CHARGING AND RECHARGING UNIT (SVU TYPE)

The unit provides stationary accumulator batteries charging and recharging.

Unit features and components:

· protection against internal short-circuits;

· protection against external short-circuits (output current limitation);

· alarm circuit;

· output voltage correction unit, providing voltage correction depending on an accumulator battery temperature (if necessary).

Specifications

Power supply voltage (3-phase)	110, 127, 220, 380 V
Max. rectified current	20, 80 A
Max. rectified voltage	300 V
Output voltage control accuracy	£ 1%
Output voltage ripple	£ 1%
Dimensions	1600 x 500 x 600 mm

MICROPROCESSOR-BASED AUTOMATIC CONTROL UNIT FOR DC SYSTEMS IN POWER FACILITIES (MSAPT)

The unit provides monitoring of condition and control of equipment of mains and DC switchboard, indication of condition of DC switchboard equipment, recording of events during operation of controlled equipment, implementation of automatic control systems for DC systems as parts of power facility automatic control systems. To provide maximum effectiveness, use the automatic switches with independent releases, equipped with numeric protection device for DC connection (ZPT-001, manufactured by OAO “Belenergoremnaladka”).

The unit is constructed as a cabinet with double-sided access. The unit includes:

· data acquisition unit (USD);

· voltage control unit (BKN);

· “Sapfir-4”, a system for automated searching for ground faults in DC circuits;

· local alarm unit (BMS);

· selective unit for insulation monitoring (UKI-SM).

NUMERIC SELECTIVE PROTECTION DEVICE FOR DC CONNECTION (ZPT-001)

The numeric selective protection device is used for operation with DC automatic unit, equipped with an independent release. The protection device provides:

· DC automatic unit disconnection in case of short circuit current during the preset dwell time;

· DC automatic unit disconnection in case of overload current;

· full test of protection device and disconnection circuit, faults indication on LED display;

· monitoring of automatic unit interlock contacts position;

· indication of protection actuation;

· recording of value and duration of overcurrents disconnected by the protection device;

· data transmission to an upper-level device using RS485 interface (MODBUS RTU protocol).

Specifications

Protection operating current	programmable
Response time	0.02 s…preset time
Reset coefficient	³ 0,95
Power	85 – 260 VDC
Power consumption	£ 5 VA
Basic processor	AduC 812
Dimensions	110 x 120 x 145 mm
Weight	1,4 kg max.
Operating temperature range	0…+70°C

LOADING RESISTANCE

The device provides testing of accumulator batteries with rated voltage 220 or 110 V and rated capacity up to 600 A/hour.

Specifications

No. of resistance setting levels	15
Maximum current (for 220 V)	50 A
Dimensions	810 x 360 x 640 mm
Weight	36 kg

SYSTEM FOR AUTOMATED SEARCHING FOR GROUND FAULTS IN DC CONTROL CURRENT CIRCUITS (“SAPFIR-4M”)

The system provides easy and reliable detection of feeder with inadequate insulation in the DC control current circuits of power facilities. For this purpose, DC control current disconnection is not required. Use a “SAPFIR-4M” portable unit to locate the specific point of connection damage.

Kit components:

· “SAPFIR-4S”stationary unit (1);

· “SAPFIR-4P”stationary unit (1);

· electromagnetic current sensor (110).

Specifications

Rated voltage in a monitored circuit	220 V max.
Sensitivity	³ 20 kOhm
Monitored circuit capacity	30 mF max.
No. of connections monitored automatically	100 (150)
Rated power supply voltage	220 V ± 10%
Dimensions	530 x 367 x 236 mm
Weight (including sensors kit)	78 kg

VOLTAGE MONITORING RELAY FOR DC BUSES (“RNS-1”)

The relay provides DC voltage increasing or decreasing monitoring in electric installations.

Specifications

Rated power supply voltage	220 V
Setting range	190…260 V
Dwell time	5 ± 0.5 s
Power consumption	£ 30 VA
Dimensions	110 x 65 x 165 mm
Weight	0,5 kg

RIPPLE MONITORING RELAY (“RNP”)

The relay provides monitoring of availability of electric coupling between an accumulator battery and DC switchboard buses.

Specifications

Rated power supply voltage	220 V
Setting range	0.2…20 V
Dwell time	2 s
Power consumption	£ 30 VA
Dimensions	165 x 110 x 65 mm
Weight	0,5 kg

DEVICE FOR TESTING LOADING OF DC AUTOMATIC SWITCHES OF ANY TYPE (“AGAT”)

The device uses primary current to test and calibrate the operating settings of built-in protecting circuits in the DC automatic switches.

Specifications

Power supply voltage	380 V, 3 phases, 50 Hz
Rectified output current	0…5000 A
Output voltage	6…18 V
Current duration during short-circuit protection checking	£ 2 s
Output voltage ripple factor	£ 2 %
Dimensions	1550 x 1000 x 600 mm
Weight	100 kg

FAULT DIRECTION INDICATOR (“UPN”)

The device records the occurrences of short-circuit current (in the position of the device connection) and subsequent line de-energizing for the purpose of determination of the faulty section in the cable line (6 – 10 kV). The device includes an indicator unit and a magnetic sensor.

Specifications

Rated power supply voltage	220 V ± 10%, 50 Hz
Power consumption	£ 6 VA
Operating current setting range	200…1000 V
Time of storage of information on short-circuit current in the cable line section (after de-energizing)	³ 6 hours

FAULT TRACER FOR 0.4 KV AERIAL LINES WITH NON-INSULATED CONDUCTORS (“POISK-0,4”)

The tracer includes a portable telescopic measuring stick, with a magnetic current sensor on the tip, and a searching pulse unit. The device provides quick location of short circuits in the lines (0.4 kV) with non-insulated conductors.

Specifications

Maximum pulse current during searching for fault	24 A
Searching pulse ratio	4 s
Current and voltage measuring precision class	£ 20
Kit weight	8 kg
Measuring stick length	6.5 m

TELESCOPIC MEASURING STICK

The device is used for quick measuring of current and voltage on the aerial lines (0.4 kV) with non-insulated conductors and points of line entrances in the buildings.

Specifications

Conductor existing current measurement range	5, 25, 50, 125 A
Conductor existing voltage measurement range	120 – 300 V
Measuring precision class	£ 10
Weight: stick case	3 kg 3 kg
Dimensions: stick in operation stick in its casing	6500 x 70 x 105 1500 x 90 x 120

MICROPROCESSOR-CONTROLLED SYSTEM FOR DETECTION AND LOCATION OF LINE-TO-GROUND INSULATION FAULTS IN 10 KV AERIAL ELECTRIC LINES (OMZAL)

System purposes:

- providing quicker detection and elimination of single-phase-to-ground faults;

- improving reliability of electric equipment operation by reducing the number of phase-to-phase short circuit faults in 10 kV electric networks, resulting from overvoltages, caused by the transients during single-phase-to-ground faults;

- decreasing the risk of fires caused by single-phase-to-ground faults.

System functions:

1. Monitoring functions: the system monitors the parameters listed below:

- zero phase-sequence voltage level (3Uo);

- phase voltage levels in 10-kV buses section;

- zero phase-sequence currents (3Io) for all 10-kV aerial lines supplied from buses section;

- current in the OMZAL system switch turned on.

2. Faulty phase determination.

3. Determination of 10-kV aerial line where single-phase-to-ground fault occurred.

4. Determination (measuring) of distance to the location of single-phase-to-ground fault.

5. Automatic bypassing of faulty phase by grounding its switch in the OMZAL system.

6. Operational functions:

- quickly run the rated grounding current measurement algorithm;

- monitor the process of appearing of single-phase-to-ground fault with very high transient resistance by monitoring the process of increasing of 3Uo voltage, initiated by 2-3 V burst;

- from time to time, record the measured parameters of existing operation mode and make it possible to transmit these parameters to an upper level (from time to time or upon the request) or store in a memory circular buffer;

- record the occurrences of single-phase-to-ground faults and the cases when the OMZAL system switches were turned on or off, and make it possible to transmit this information to an upper level (from time to time or upon the request) or store in a memory circular buffer;

- record, save and transmit the real time stamps of events and their parameters;

- test the OMZAL system microprocessor unit operability and the switch control circuit power supply condition, and provide appropriate information in case of fault.

AUTOMATIC ADJUSTING UNIT FOR ARC-SUPPRESSION COIL (“BANK-10”)

The unit is used for automatic adjustment and remote control of continuously adjustable (plunger-type) arc-suppression coil drive. The arc-suppression coil provides compensation of capacitive currents in a cable network (6…10 kV).

Specifications

Rated power supply voltage	220 V ± 10%, 50 Hz
Rated voltage (Uon)	100 V ± 10%, 50 Hz
Settings adjustment range	³ 60 electrical degrees
Dwell time for actuation	30 ± 5 s
Power consumption (for Uon)	£ 5 VA
Dimensions	370 x 210 x 180 mm
Weight	6 ± 0,5 kg

AUTOMATIC AND REMOTE CONTROL KIT FOR ARC-SUPPRESSION COIL (“KADU DGR”)

The kit is used for automatic adjustment and remote control of continuously adjustable (plunger-type) arc-suppression coil drive.

Kit components:

· automatic adjusting unit (BANK);

· power switching unit (BSK);

· neutral shift unit (BSN).

Specifications

Rated power supply voltage	380 V
Voltage (Uon, BANK unit)	100 V ± 10%
Settings adjustment range (BANK unit)	³ 60 electrical degrees
Dwell time for actuation	30 ± 5 s
Power consumption (for KADU DGR)	£ 20 VA
Dimensions	960 x 610 x 300 mm
Weight	90 ± 5 kg

MICROPROCESSOR-CONTROLLED DEVICE FOR GENERATOR AND EXCITER BEARING INSULATION MONITORING (UKIP-1)

The device provides continuous monitoring of condition of underchair insulation and oil film insulation in the generator shaft sealing, the generator bearings and the exciter, including:

· device operability self-testing;

· power source condition monitoring;

· storage of information concerning faulty components and time of fault occurrence;

· transmission of information, concerning the device operation or fault, to the information system on the customer’s plant;

· faults indication using the LED display.

Specifications

Rated voltage	220 V
Rated power	16 VA
Voltage applied to the generator shaft	2 – 10 V
Weight	5 kg max.

GENERAL SELECTIVE GROUND-FAULT PROTECTION DEVICE (GSPAG)

Device functions:

· protection of the section, as a whole, against single-phase-to-ground faults on the cable lines, 6(10) kV, powered from the substation bus section and equipped with zero phase-sequence current transformers, affecting the line switch disconnection or the signal;

· protection locking in case of external single-phase-to-ground faults (in 6(10) kV network, electrically coupled with the system under protection) or in case of disconnection of a lead-in switch in the bus section, including appropriate information output;

· the time interval between single-phase-to-ground fault occurrence and protection actuation is 20 ms or more;

· in case of short-time single-phase-to-ground faults, with a duration less than a protection actuation time, the faulty connection is indicated;

· the protection device provides monitoring of insulation condition (ground faults) for the network connected to the device;

· recording, storage and transmission of the real time of event occurrence;

· protection device operability testing and fault indication if necessary;

· quick “trial operation” of protection, affecting the switches disconnection or the signal.

Specifications

Power supply voltage	100 VAC +15%, -20%
No. of protected cable connections	6 or 12 (as required)
Protection actuation time	20 ms…1,5 s
Communication interface	RS232, RS485

The LED displays provide the operating personnel with full information concerning protection operation and electric network condition.

DEMAGNETIZATION DEVICE (UR)

The device provides demagnetization of turbo unit parts and assemblies, decreasing their magnetization to acceptable levels.

The demagnetization device includes:

- power unit;

- magnetic field induction indicator and sensor;

- demagnetizing winding;

- power unit cable.

The power unit includes three-phase transformer with double-star connection, 380/35 V, two three-phase controllable thyristor-based rectifier bridges and the microprocessor control unit.

The magnetic field induction indicator digitizes the information, obtained from the magnetic field induction sensor, and transmits the value and the vector of magnetic induction, in a digital form, to the microprocessor control unit for using in a demagnetization algorithm.

Manual or automatic demagnetization mode is possible.

The device is used in the maintenance works of the electric power plants.

Specifications

· The device implements its primary function by applying the current, with appropriate magnitude and polarity, to the demagnetizing winding.

· Power supply: 342-418 VAC, three phases, standard frequency.

· Power consumption during generation of maximum demagnetizing current: 20 kVA max.

· The output current comprises unidirectional pulses of various directions.

· Current pulse magnitude adjustment range: 1…400±2 A.

· Current pulse and pulse-to-pulse intervals time adjustment range: 1…99±0,5 s.

· Magnetic field induction indicator sensitivity: 0.1±0.01 T or better.

· Maximum magnitude of magnetic field induction that can be displayed by the indicator: 15±0.1 T.

THERMOGRAPHIC INSPECTION OF THERMAL AND ELECTRIC EQUIPMENT ON THE POWER FACILITIES

Computer-aided thermography makes it possible to obtain the images (thermograms) of thermal radiation, emitted by the equipment and invisible for a human. Using this method, it is possible to reveal heavy heat losses that are, as a rule, the indicators of faulty or inadequate thermal insulation or poor contacts. The method does not require any contact with the equipment, heated as a result of a defect growth.

Application of computer-aided thermography makes it possible to reveal the equipment faults at their early stages, to prevent emergency shutdowns that result in gross expenses, to schedule the repairs and maintenance procedures, to evaluate maintenance quality on the grounds of real data.

At present, OAO “Belenergoremnaladka” has gained considerable experience in these procedures, and has carried out thermographic inspections of electric equipment in many electric power plants and substations of the Belarusian power system. As a result, many faults were revealed, including those that could result in emergencies.

Using the computer-aided thermography, it is possible to test:

- contact connections in open and closed distribution devices;

- supporting bar-type insulation and suspended insulation;

- internal contact connections of switching units;

- oil-filled equipment;

- power transformers;

- brush assemblies in generators and accumulator batteries;

- chimneys lining.

The computerized thermograph, “IRTIS-200”, is used for thermographic inspections. The computerized thermograph specifications are as follows:

- receiver with liquid-nitrogen cooling;

- temperature measurement range: -20°C…+200°C (expandable up to +1300°C);

- permissible error margin: ±1% from measured value;

- temperature sensitivity: 30°C – 0.05°C;

- spectral range: 3.0 – 5.0 mm.

OAO “Belenergoremnaladka” offers services in thermographic inspections of electric equipment and contact connections in electric power plants and substations (110 – 330 kV).

FULL-SCALE STARTING-UP AND ADJUSTING PROCEDURES
FOR A NEW GENERATOR COMMISSIONING

Adjusting procedures on an idle generator with a rotor rolled out from a stator:

- use a TV endoscope to evaluate the stator winding condition in the generator;

- use a TV endoscope to evaluate the rotor winding condition in the generator;

- carry out an ultrasonic inspection of the active steel in the stator;

- check a condition of the structural component;

- measure the parameters (R60/R15) of the stator winding insulation in the generator, and determine the required test voltage magnitudes (50 Hz test voltage and rectified test voltage);

- use a rectified test voltage to test the stator winding insulation and to determine the nonlinearity factor of an insulation leakage current;

- use an increased test voltage (50 Hz) to test the stator winding insulation;

- measure the parameters of the rotor winding insulation;

- measure the rotor AC resistance;

- measure the stator winding DC resistance;

- carry out a chromatographic analysis of hydrogen from the generator case;

- to provide fair automated inspection of the condition of cores in high-power electric machines, before and after repair, several times scan a stator bore after outage for repair (with a rotor rolled out) and after completion of a repair, to check its quality.

Adjusting procedures on an idle generator with a rotor placed into a stator and with closed end shields on a generator:

- apply an increased AC voltage to measure the insulation resistance and to carry out a check test of the stator winding insulation;

- measure the parameters of the rotor winding insulation;

- measure the rotor AC resistance.

Adjusting procedures the rotating electric machine:

- determine the short-circuit characteristics;

- determine the no-load characteristics;

- test the generator turn insulation;

- measure the residual voltage on the generator lead-outs.

In accordance with the tests results, the generator condition report is issued.

Starting-up and adjusting procedures for the generator exciting systems commissioning:

Starting-up and adjusting procedures on a high-voltage side:

- primary equipment (switch etc.);

- control circuits, relay protection circuits and automatic equipment for the generator alarm systems;

- generator synchronization systems.

Starting-up and adjusting procedures on a low-voltage side:

- control, protection and automatic operation circuits for motors (operating the circulation pumps, oil pumps etc.);

- power assemblies equipment (PR-85, RTZO-88);

- balance-of-plant switchgear (RUSN) 0.4 kV.

Starting-up and adjusting procedures for the power transformers commissioning: full range of works stipulated by the “Electric Equipment Tests Procedures and Schedules” Regulation.

Preparation of instructions: operation instructions for newly commissioned equipment, including the generator, exciting system, transformers, brush contact equipment (if applicable), motors, relay protection circuits and automatic equipment for standby lead-ins, generator protection microprocessor-controlled terminals, generator rotor ground fault protection kits, manual and automatic synchronization devices, power equipment switchgear (KRU) 6-10 kV, balance-of-plant switchgear (RUSN) 0.4 kV, distribution devices (RU) 110 kV, electromagnetic polarized relays; instructions for elimination of faults of electric equipment; fire safety instructions.

ELECTRIC EQUIPMENT TESTING LABORATORY (IL 30)

Services:

- power transformer tests, stipulated by the “Belarusian Power System Electric Equipment Tests Procedures and Schedules” Regulation;

- protecting cutout device tests;

- electric physical measurements.

The power transformer testing and troubleshooting procedures shall provide:

- meeting the regulations requirements;

- more exact determination of scope of repair works before their commencement;

- defect characterization and location, and selection of defect elimination methods, using both conventional and new troubleshooting procedures;

- extension of inter-repair intervals.

Measurements and tests carried out by the Laboratory:

a) load and no-load tests:

- chromatographic analysis of gases dissolved in oil (Customer’s data may be used, with additional verification an the Society’s laboratory);

- paper insulation ageing evaluation, based on the analysis of furan compounds concentration in oil;

- oil physical and chemical parameters determination;

- winding and magnetic conductor compressing level determination, based on no-load and load vibration tests;

- partial discharge presence detection (since April 2008);

- no-load and load tests for detection of leakage overflux, closed on the tank walls (Society’s proprietary procedure);

- no-load current waveform oscillographic recording, comparison with standard waveforms, and harmonic analysis;

- oil pump bearing condition evaluation, based on measured vibration characteristics;

- thermographic inspection of the transformer tank, expansion tank, oil pump and other components;

- visual inspection of transformer components for evaluation of their condition;

b) with the transformer turned off, the Laboratory carries out full range of tests, stipulated by the “Belarusian Power System Electric Equipment Tests Procedures and Schedules” Regulation;

c) after lifting the bell:

- inspection of transformer components visually and using an endoscope, in accordance with the special procedure;

- grounding availability checking and condition testing, in accordance with the manufacturer’s circuit diagram;

- structural components insulation resistance measurement;

- magnetic conductor parameter measurement and detection of steel plates bridging;

- handling devices inspection;

d) undervoltage relay testing and troubleshooting in accordance with the requirements of factory tests:

- circular graph plotting;

- contactors operation waveform oscillographic recording;

- drive force measurements;

- resistors resistance measurements;

- contacts condition checking.

During overhauls, the magnetic conductor parameters are measured to reveal faults in the transformer steel; also, the faults in windings and structural components are detected.

Upon the repair completion, subject to the agreement with the Customer, the procedures are carried out, intended to verify the results of defects elimination (thermography, chromatography, transformer case leakage tests etc.).

Accreditation certificate: BY/11202.2.0.2691 (September 20, 2004)

Contact telephone numbers: (+375 17)293 57 29, (+375 17)293 53 29

ACCREDITED VERIFICATION LABORATORY

The Laboratory carries out repair and verification of measuring instruments.

Electronic measuring instruments:

- low-frequency generators;

- electronic analog voltmeters;

- digital frequency meters (F246);

- relay parameter meters;

- line discontinuity meters (R5-10);

- short-circuit current meters;

- DC power supplies.

Electric measuring instruments:

- electronic megohmmeters / microhmmeters (F4102, F4103, F4104, ISK, M416, ESO);

- megohmmeters / microhmmeters (M4100, M1101, KMS-77);

- pointer instruments: ammeters, voltmeters, kiloammeters, kilovoltmeters, frequency meters (both obsolete and up-to-date), multimeters (Ts43101, Ts4317, and up-to-date digital multimeters), multi-range instruments (class 0.2, 0.5 and higher, both AC- and DC-type);

- recording instruments (frequency meters, kiloammeters, kilovoltmeters);

- tong-test instruments (practically all models listed in the State Register of the Republic of Belarus);

- transducers (power, frequency, voltage, current), including summation ones;

- electric stopwatches;

- AC bridges (R5026 and similar), DC bridges (R333 and similar);

- AIM-90 and similar.

Measuring instruments for nondestructive tests:

- ultrasonic thickness gauges;

- ultrasonic flaw detectors, including up-to-date instruments (UD2-70, UD2-102, UD-4T).

Thermal measuring instruments:

- gas analyzers (including up-to-date instruments, such as KGA-8S, TDK-3M, GAMMA-100);

- pH meters;

- tachometers;

- pressure gauges, pressure transducers (METRAN type). The Laboratory has an equipment making it possible to repair and verify the pressure gauges with 0…60 MPa measurement range;

- secondary devices (amplifiers, regulators, starters etc.).

Also, the Laboratory provides other services: case repair, glass and damping liquid replacement, braces installation, transformer rewinding, sophisticated repair of electronic and electric measuring instruments, measuring instruments industrial-level verification and preparation for national-level verification.

Accreditation certificate: BY/112.02.3.0.0086 (November 11, 2002)

Contact telephone numbers: (+375 17)293 53 42