After wiring is completed in a substation or distribution room and the power quality analyzer is started, if there are large deviations in voltage and current values or an abnormal power factor, this is usually related to the wiring method, range settings, or signal connection sequence. During troubleshooting, first confirm whether the secondary side of the voltage transformer is short-circuited and whether the secondary side of the current transformer is open-circuited, then check whether the instrument's wiring group matches the on-site configuration. At some sites, due to strong harmonic interference, the instrument's built-in anti-aliasing filtering function needs to be enabled to prevent high-frequency components from affecting fundamental wave calculations.
The power quality analyzer uses a high-speed ADC to convert analog signals into digital signals at a sampling rate of 256 to 512 points per cycle, and then the DSP chip performs FFT transformation to separate the fundamental wave and each harmonic component and calculate parameters such as RMS values, active power, and phase. During routine maintenance, a standard source should be used regularly to verify the consistency of the sampling channels. If amplitude or phase drift is found in a certain phase, check whether the ADC front-end conditioning circuit and wiring terminals are oxidized or loose. For instruments that are not used for a long time, it is recommended to power them on once a month to prevent electrolytic capacitors from aging.
According to GB/T 19862-2016 "General Requirements for Power Quality Monitoring Equipment," the power quality analyzer needs to continuously measure steady-state indicators such as voltage deviation, frequency deviation, harmonics, and three-phase unbalance. When setting the continuous recording interval, technical engineers should adjust the storage depth according to the on-site load change cycle to avoid storage overflow caused by too short a recording interval. When measuring harmonics, pay attention to distinguishing harmonic orders from interharmonics, and if necessary, enable the instrument's event trigger function to capture transient fluctuations.
The instrument should be stored in a dry, ventilated environment free of corrosive gases. The operating temperature is recommended to be controlled at 0 to 40°C, and the relative humidity should not exceed 80%. When taking power on site, give priority to using the instrument's own power adapter to avoid introducing interference by taking power directly from the switchgear control circuit. For long-term outdoor use, prevent direct sunlight and rain splashing, and regularly check whether the cooling fan and vents are blocked. During transportation, use the original shockproof case to avoid severe impacts affecting the internal connectors.
It is recommended to send the instrument for inspection every 12 months. Calibration items include basic voltage and current errors, power measurement errors, harmonic content rate errors, etc. During on-site use, a zero drift check can be performed before each test, and data should be exported and backed up promptly after the test is completed. Records stored inside the instrument should be cleaned up regularly to avoid new data overwriting old records due to insufficient storage space. If the measurement results are found to deviate from a known standard meter beyond the allowable range, stop using the instrument and contact professional personnel for repair.
