TESTING AND COMMISSIONING OF ELECTRICAL EQUIPMENT DC UPS

The main keywords for this article are testing and commissioning of electrical equipment, ups test, commissioning and testing and commissioning of dc ups system. 

TOOLS AND EQUIPMENT TESTING AND COMMISSIONING OF ELECTRICAL EQUIPMENT

Tools and equipment should be in good condition for use in the construction area. All test equipment required to be calibrated not more than 3 months before the date of test. All equipment calibration “original” certificates should be presented at site.

These includes but not limited to the following:

  • Common Hand Tools
  • Digital Volt-ohm Meter
  • 500/5000V MEGGER
  • Current Tester (Multi-Amp or equal)
  • Torque Wrench
  • Ductor (Micro ohm Meter)
  • Protective Relay Test Set
  • Thermometer
  • Oscilloscope
  • Load Bank
  • Manufacturer’s Instruction Manuals
  • Personal Protective Equipments
  • Timing Tester
  • Hydrometer
  • Relay testing set
  • DLRO

PROCEDURES TESTING AND COMMISSIONING OF ELECTRICAL EQUIPMENT

GENERAL PREPARATORY WORKS

  • COMPANY shall appoint qualified employees as their ‘competent persons’. Such persons shall be capable of working safely and shall be knowledgeable on the precautionary techniques, personnel protective equipment, shielding and insulating materials and tools.
  • All permanent and consumable materials shall prepare prior to testing.
  • Manpower, equipment, tools and other logistics shall be prepared and ready for installation.
  • Prepare the workplace such as barricading the area and housekeeping.
  • Review the AC/DC control schematic of the disconnect switch assembly. All connection diagram vendor and IFC drawing shall be available in the work area.
  • Review all technical specifications, operating manuals and previous inspection data if appropriate.
  • Electrically Hazardous Task Plan / Permit shall be completed and signed before any work proceeds.

DC UPS SYSTEM

Visual Inspection

Compare equipment nameplate information data with actual operating conditions, drawings and specifications.

Inspect the physical condition of all electrical and mechanical components for deterioration and missing, broken, or loose parts, etc. Complete visual inspection of the battery system as follows.

  • Broken or missing flame arresters and caps.
  • Sediment in the bottom of batteries.
  • Cracked, swelled, or damaged battery cases.
  • Abnormal battery plate appearance.
  • Visible corrosion on battery terminals or battery rack.
  • Normal excessive ambient temperature in battery room.
  • Normal excessive ambient humidity in battery room.
  • Normal excessive dust or dirt in battery room.
  • Wet floor around batteries and electrolyte on tops of batteries.

Inspect for battery and racks are properly installed.

Check for proper battery terminal and grounding connection are done.

Tighten main current carrying part (terminal connection, etc.) to the manufacture torque specification. If such information is not available, tighten in accordance with SA-P-000 page 4. Ductor test may also be used to confirm proper connection after initial torque test has been completed.

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Input Transformer check

  • Check the availability of the rectifier incoming isolation transformer.
  • THDI shall not exceed 10%.
  • Hottest-spot winding temperature rise shall not exceed 145°c.
  • Cable connection shall not exceed 50°C in an ambient temperature of 40°C.

Input overcurrent protection check

Check the availability of the rectifier input circuit breaker for overcurrent and short circuit protection.

Input surge protection check

Check the availability of the surge protection in the input circuit of the rectifier.

Output surge protection check

Check the availability of the surge protection in the output of the rectifier.

Operation without battery check

Verified that all performance test shall be carried out without the battery connected in order to verify that the rectifier meets the entire performance required in the specification.

Output overcurrent protection check

Check the availability of an automatic circuit breaker in the rectifier output for overcurrent and short circuit protection, and also to provide a means of disconnecting the charger from the load.

Battery end of discharge voltage protection check

Check the availability of an enclosed battery circuit breaker with low DC voltage disconnect feature. The device shall disconnect the battery from the circuit when end of discharge voltage is reached (105.4V) and the nominal voltage is 125V.

Reverse polarity protection check

Check the availability of a device to protect the charger against accidental reverse polarity connection in the battery terminals.

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Electrical Commissioning Test

Performed function test. Verify that the control equipment, auxiliaries, protection equipment and main circuit are operation properly together.

  • Function test of the control devices. The correct operation of each circuit regarding the system control logic (either electronic or electromechanical) shall be checked.
  • Functional test of the auxiliary devices. The correct operation of auxiliary devices such as contactors, pumps, sequencing equipment, fans, etc. Shall be checked. If convenient, this can be done in conjunction with the light load test.
  • Functional test of the protective devices. The correct operation of all electronic protections from both overloads and short-circuits shall be checked.
  • Functional test of the alarm devices. The correct operation of circuits regarding both local and remote (available on voltage-free contacts) alarm signals (either acoustic or luminous) shall be checked.
  • Functional test of the signalization devices. The correct operation of all luminous signals available on front panels shall be checked.

Performed rated current test, to verify the equipment will operate satisfactorily at rated current.

Rectifier input current walk-in ramp – A resistive load shall be applied in the rectifier output, the rectifier shall be switched ON and shall be verified that the rectifier AC input current gradually increase up to nominal value in a time greater than 10 seconds.

DC output current limit check – To check the correct operation of the system at the rated current. The system shall be connected to the rated supply voltage. The load used for the test, only resistive, will consist of about 100% of the rated load.

The equipment shall an output voltage equal to the rated voltage value and no over temperature problems shall occur.

Verify that applying some other additional load, the overload alarm will be activated and the rectifier output voltage starts to reduce. Its output current will be remain approximately about 115% of nominal value.

Float voltage check – With the rectifier operating in normal condition, verify that the floating charge voltage setting shall be adjustable in a range from 2.15V/cell to 2.35V/cell at 25°C battery temperature.

Equalize voltage check – With the rectifier operating in normal condition, verify that the equalizing charge voltage setting shall be adjustable in a range from 2.20V/cell to 2.45V/cell at 25°C battery temperature.

Temperature compensated charging check – Shall be verified that the temperature sensor for the battery charging voltage temperature compensation has been provided and connected to the rectifier. By simulating an increment or decrease in the ambient temperature, shall be verified that the rectifier output voltage shall respectively decrease or increase of 3mV/cell/°C for changes in the temperature.

Abnormal load condition check – Shall be verified that the charger is able to operate into zero battery voltage without activating protective device.

  • Disconnect both the alternating current supply and the battery.
  • Set the battery charger in the float mode and place a short circuit across its output terminals.
  • Supply the battery charger with nominal input power.
  • Wait one minute while the system is operating in short circuit condition.
  • Switch off the input power and remove the short-circuit.
  • Load the battery charger resistively to check its ability to deliver rated output current.

 

DC/DC converter parallel operation check – Shall be verified that the two DC/DC converters are suitable to operate in Parallel condition and sharing the common load. Shall also be verified that a blocking diode (rated for the maximum output current of the rectifier/charger) shall be placed in the ungrounded output of the charger.

Performed rectifier static stability test. Test shall be carried out from no load to 100% load condition on floating and equalizing charge, so that almost all possible conditions during the real operation may be simulated. It shall only deal with .resistive loads. As far as each condition is concerned, output voltage and current will be measured as

respectively referred to the rated supply voltage and its minimum and maximum values of the whole allowed range of variation of the mains supply such as +/-10% voltage variation.

Measurement of the rectifier output ripple voltage. Test shall be carried out from no load to 100% load condition, so that almost all possible conditions during the real operation may be simulated. It will only deal with resistive loads. As far as each condition is concerned, the rectifier output ripple root mean square voltage VRMS at the terminals of the connected battery will be measured, as referred to the rated supply voltage and to its minimum and maximum values, within the whole allowed range of variation of the mains supply.

Performed DC/DC converter static stability test. Test shall be carried out from no load to 100% load condition and floating and equalizing, so that almost all possible conditions during the real operation may be simulated. It shall only deal with resistive loads. As far as each condition is concerned, output voltage and current will be measured as

respectively referred to the rated supply voltage and its minimum and maximum values of the whole allowed range of variation of the supply voltage.

Dynamic test of DC/DC converter load variation

The system shall be fed according to the mains supply rated voltage. Only purely resistive loads shall be used. Such test will consist of two parts, corresponding

respectively to the insertion and disconnection, as follows:

Load Insertion. The system is subject to a sudden load variation, first at 10% of the rated load, then up to 100% of the rated load.

Load Disconnection. The system is subject to a sudden load change, first at 100% of the rated load, then up to 10% of the rated load.

Burnin Test, during such test, the system shall be connected to the rated mains supply voltage and connected to a pure resistive load equal to 100% of the rated load. Such system will operate accorpreding to these conditions for 8 hours. During the whole test, the output current, voltage values and temperature in the most critical points through thermocouples will be read on a regular time basis. commissioning of electrical equipment.

Battery Charger and Rectifier Test Procedure

The main keywords for this article are testing and commissioning of electrical equipment, ups test, commissioning and testing and commissioning of dc ups system. 

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