Power quality monitoring deviceIt is a device used to monitor power quality and plays an important role in the stable operation of the power system.Power quality monitoringThe device requires high instrument accuracy and accuracy, which is the key to ensuring the accuracy of power quality monitoring data. This article will start with two aspects of instrument precision and accuracy, and delve into them in depthPower quality monitoring deviceThe calculation method for accuracy and precision.

Calculation method for instrument accuracy

Instrument accuracy refers to the difference between the measurement results of an instrument and the true value being measured. The instrument accuracy in the power quality monitoring device can be calculated using the following two methods.

Method 1: Statistical methods

Statistical methods are used to calculate instrument accuracy through certain statistical methods. This method requires collecting multiple sets of data first, and common statistical methods such as mean, variance, etc. need to be used when processing the data. The calculation formula is as follows:

Accuracy=(standard deviation of measured values/average of measured values) × one

The result calculated by this formula can measure the percentage of measurement error of the instrument. The higher the accuracy, the smaller the measurement error.

Method 2: Evaluation Test Method

The evaluation experiment method adopts a certain comparative analysis method to evaluate the accuracy of the instrument. In order to meet the accuracy requirements, it is necessary to select appropriate standard devices for testing and compare the measured values of the standard devices with the measured values. The calculation formula for this method is as follows:

Δx = m × S A = Δx / 2e

among Δ X is the difference between two measured values, m is the probability factor found in the t-distribution table, S is the standard deviation (calculated based on sample size and confidence), and A is the error.

After calculating the error using the above formula, the relative error can be calculated based on the obtained formula, making it easier to evaluate the accuracy of the instrument.