1ST.Quickly and accurately test all parameters of power filter by this single device, including:
- Amplitude-frequency characteristic and phase-frequency characteristics
- Inductance value of reactor
- Capacitance value of capacitor
- Resistance value of resistor
- Unbalanced current of filter bank H bridge
[Now, it’s the unique universal test equipment in the world. ]
2ND.Can measure the capacitance without un-tapping capacitor connections.
[Although ABB's CB2000 can also measure the capacitance without unfastening wires it is not able to measure other parameters (e.g.: inductance, resistance, A-F characteristic and P-F characteristic)]
3RD. For the resonance test, it can realize:
- Automatically display the A-F characteristic curve
- Automatically display the P-F characteristic curve
- Automatically generate the test report in word format
[At present the traditional method of measuring the resonant point is to manually measure each test point and hand-drawn curve. It can’t automatically generate and save test reports.]
4TH. High precision: field test accuracy can reach 5 ‰.
[Meet the highest international standard on testing filter banks.]
5TH. High efficiency: compared to the traditional testing methods it saves much time and labor force.
[To test a power filter it needs less than10 minutes by PF3000 comparing to 2-3 hours by traditional methods.
Traditional method uses variable frequency power source to output test signal to the filter under test. High precision voltage and current meters must be used in the test and the test results have to be calculated manually to get the A-F and P-F curve display.]
6TH. Safe and reliable: using high-frequency low-level signaldoesnot generatedangerous high voltage. Thus no safety issue is in the picture in the field.
[When using traditional method to measure the frequency micro ampere meter and the voltage regulator must be used.And it requires 400Vac signal and this high voltage brings security implications to the field testers.]
Why choose PF3000
Unbalance current reflects the balance among filter banks
1. Unbalance current in H-bridge of power filter is the important index for power filter operation. The zero current in H-bridge indicates the perfect balance among filer banks. On the contrast the current flow in H-bridge means that the balance among filter banks has been broken. This unbalance current must be eliminated by adjusting the filter parameters, such as capacitor value, to ensure the filter banks in good situation.
Unfortunately before PF3000 is launched there is no such type of tester which can test the unbalance current and the way to keep filter banks balanced is quite complicated and time consuming. The normal steps are as follows:
- Measure the capacitor individually and calculate the average capacitance C,
- Then, you can get the capacitance value of each arm of the bridge C’=C+Cï¼Œ
- Then, through the deviation C to adjust the balance.
This method is very complicated. It needs un-tapping the capacitor bank and measure it one by one, which is time consuming and inefficient. PF3000 using unbalanced current measurement method, it only need measure the total current vectorIc which follows through the “H” bridge capacitor group and the unbalanced current vector Ibph which follows through the neutral line of the “H” bridge.The filter bank is adjusted balance only when the unbalance current vector Ibph became zero.
The new method greatly improve the capacitor test efficiency
2. Measure capacitance without un-tapping the capacitor banks: when adjusting the balance if you want measure the capacitance of each capacitor of the filter bank, you can measure it directly, unnecessary to un-tapping the capacitor. It greatly saved time. Use PF3000 more efficient than traditional methods.
Reduce the use of variable frequency signal source test error
3. Using variable frequency signal source: the output of PF3000 is a variable frequency signal. When it simulates the industrial frequency on the scene, we generally choose a high frequency low-level signal. On one hand, it is light portable and convenient, on the other hand, using voltage regulator and micro ampere meter equivalent to series a 1KΩ internal resistor so it brings an error to the measurement on the scene. The error is about 15% using the PF3000 can eliminate the error from traditional method.
The use of powerful software and user-friendly interface makes testing easier
4. Using software simulation: when do the tuning tests, after an actual measurement, we use the software simulation function to vary the parameters in the filter (inductance parameter). Because the gears of the inductance are composed of multiple taps.Permutations and combinations methods are used to choose the appropriate taps. When the parameters were changed (Increase or Reduce) observe the tender of resonant point after simulation to get more close to the ideal resonant point. At last,select the appropriate gears of the tap to be measured.
5. Using software filtering function:we develop a filtering algorithm in the software. It can filter all the harmonic signals except the set frequency so the result of the samples will become a standard signal.
6. Using software analysis:
When do the tuning test, we set the different frequency segments depending on the difference of the filter.
Choose an appropriate step in the frequency segment to ensure the test precision and efficient.
- Variable frequency source output power signal
- Collect the voltage and current signal synchronously and display to observe if the wave form is abnormal.
- The R-F curve is displayed automatically.
- The word format test reports can be generated and saved.