The test of UPS power supply generally includes steady state test and dynamic test. The steady state test is to test the output voltage, frequency, output voltage waveform and power under the conditions of no load, 50% additional load and 100% additional load. The primary intent of testing UPS is to identify whether the practical technical objectives of UPS are satisfactory for application requirements. In order to ensure that the performance of the UPS system meets the requirements of normal operation, the UPS system must be tested before the UPS is put into operation in the data center. Today we will introduce it in detail:
1. Waveform
Generally, under no-load and full-load conditions, observe whether the waveform is normal. Use a distortion measuring instrument to measure the distortion of the output voltage waveform. Under normal operating conditions, connect a resistive load, and measure the relative content of the total harmonics of the output voltage with a distortion measuring instrument, which should meet the requirements of the product regulations, generally less than 5%.
2. Steady state test
The so-called steady-state test refers to the test when the equipment enters the "system normal" state, and generally can measure the waveform, frequency and voltage. The frequency can generally be measured with an oscilloscope to observe the frequency of the output voltage and a "power disturbance analyzer". Now the output voltage frequency of UPS power supply can generally meet the requirements. However, when the frequency circuit of the UPS power supply and the local oscillator are not accurate enough, it is also possible that the frequency of the UPS output voltage also changes when the mains frequency is unstable. The accuracy of the UPS output frequency can generally reach plus or minus 0.2% when synchronized with the mains.
3. Power
The power of UPS can be obtained by measuring the output power and input power of UPS. UPS power supply is primarily determined by the design of the inverter. Most UPS power supply only has a relatively high power when the load is 50%-100%. When the load is less than 50%, the power will drop sharply. The power target provided by the manufacturer is mostly under the condition of extra DC voltage and extra load. power. It is best to choose the relationship curve between power and output power and the power when the DC voltage changes by plus or minus 15%.
4. Output voltage
The output voltage of the UPS power supply can be tested and judged by the following methods:
A. When the input voltage is 90% of the extra voltage and the output load is 100% or the input voltage is 110% of the extra voltage and the output load is 0, the output voltage should be kept within the scale of plus or minus 3% of the extra value .
B. When the input voltage is 90% or 110% of the extra voltage, one phase of the output voltage is no load, and the other two phases are 100% load, the output voltage should be kept within the scale of plus or minus 3% of the extra value. The phase difference should be kept within 4 degrees.
C. When the input DC voltage of the UPS power supply inverter changes by plus or minus 15% and the output load changes by 0-100%, the output voltage value should be kept within the plus or minus 3% of the extra voltage value. This goal is superficially duplicated with the aforementioned goal, but in practice it is more demanding than the previous goal. This is because when the input signal of the control system changes in a large scale, it shows significant nonlinear characteristics. If the output voltage does not exceed the allowable scale, the circuit requirements are higher.