HDXL Inter-frequency Transmission Line Parameter Tester Wiring Method Instructions

In the traditional power frequency parameter testing of transmission lines, three-phase autotransformers and large-capacity isolation transformers are used to provide test power, and CT and PT used for power measurement are used for electrical signal conversion. Finally, pointer-type high-precision voltmeters and ammeters are used , the power meter measures each electrical parameter, and finally calculates the power frequency parameter test results of the transmission line. The whole set of test equipment is large in size and weight, and requires the cooperation of a crane, which is very unfavorable for on-site measurement. Moreover, because the test power supply is a power frequency power supply, it is easily mixed with coupled power frequency interference signals, resulting in large measurement errors. The signal-to-noise ratio needs to be greatly improved, which further increases the capacity and volume of the power supply.

This instrument can accurately measure the power frequency parameters (positive sequence capacitance, positive sequence impedance, zero sequence capacitance, zero sequence impedance, mutual inductance and coupling capacitance of various high-voltage transmission lines (overhead, cable, overhead cable hybrid, multi-circuit erection on the same pole) etc.), fully meets the requirements of the "Start-up Acceptance Regulations for Power Transmission and Transformation Capital Construction Projects of 110 kV and above", DL/T559-94 "Operation Setting Regulations for 220-500kV Power Grid Relay Protection Devices", and "GB50150-2006".

The instrument adopts an integrated structure with built-in variable frequency power module and variable frequency voltage-regulated output power supply. The use of digital filtering technology avoids the interference of power frequency electric fields on the test and fundamentally solves the problem of accurate measurement under strong electric field interference.

1. Quickly and accurately complete the measurement of positive sequence capacitance, zero sequence capacitance, positive sequence impedance, zero sequence impedance and other parameters of the line. It can also measure the mutual inductance reactance and coupling capacitance between lines;

2. It has strong anti-interference ability and can accurately measure under the condition that the ratio of inter-frequency signals and power frequency signals is 1:10;

3. The external wiring is simple, and only one lead wire of the line under test can be connected to complete all line parameter measurements; it completely solves the problems of tedious test wiring switching, interference, stability, accuracy, etc. existing in existing testing methods.

4. The instrument uses a high-speed microcontroller as the core to integrate test power supply, instruments, and calculation models, condensing a truck of equipment into one instrument.

5. The instrument uses a 320*240 large-screen dot matrix LCD display, a rotating mouse imported from the United States for operation, and an embedded Chinese character micro-printer for printing results, making the operation very easy;

6. The instrument testing process is fast. The instrument automatically completes the test mode control, voltage rise and fall control, data measurement calculation, and prints the measurement results. The measurement of one sequence parameter is completed in one minute. The test time is shortened and the workload is greatly reduced. Within 20 minutes Can complete two hours of work using traditional methods;

7. The measurement accuracy is high. The instrument itself provides three sets of different frequency power supplies close to the power frequency (42.5Hz/57.5Hz 45Hz/55Hz 47.5Hz/52.5Hz) to choose from, which can easily separate the power frequency and clutter interference, and effectively achieve small High-precision measurement of signals;

, test wiring

Preparation before starting the test

◆Connect the measuring end of the line under test to the ground reliably.

◆Connect the ground terminal in the upper left corner of the instrument panel to the ground reliably.

◆Connect the power output signal ground N to the earth reliably.

◆Connect the instrument test power output terminals A, B, and C to the line measurement down leads.

◆Connect the instrument test terminals UA, UB, and UC to the line measurement down leads.

As shown in Figure 5-1, after the instrument test wiring is completed, open the grounding of the down wire to ensure the safety of the equipment and operators.

Figure 5-1 Schematic diagram of on-site test wiring

If the test down lead only leads to 3 terminals, try to use wires with a large enough cross-sectional area and ensure reliable connection with the line measurement end to avoid introducing large wiring errors.

The instrument test wiring is extremely simple. You only need to connect the above test lines once, and through the automatic control measurement method of the instrument and the end-to-end wiring method of the line under test, all sequence parameter measurements can be completed, greatly improving test efficiency and operational safety.

1. Induced voltage measurement

For the measurement of induced voltage, in the first line of the measurement options, press the mouse vertically after selecting it, and the instrument will automatically measure the three-phase induced voltage. The wiring is shown in Figure 5-1

2. Positive sequence capacitance test wiring and opposite end operation

Before performing the positive sequence capacitance test, the induced voltage of the line must be measured. If the induced voltage of any phase on the three-phase line exceeds 100V, the anti-interference device equipped with the instrument needs to be connected between UA, UB, UC and N on the panel. space, as shown in Figure 5-2.

The measurement of induced voltage is in the first line of the measurement options. After selecting it, press the mouse vertically and the instrument will automatically measure the three-phase induced voltage.

Figure 5-2 Wiring diagram after positive sequence capacitance test and anti-interference device installed

In the positive sequence capacitance (positive sequence open circuit) test, the opposite end of the line under test (relative to the measurement end) is open, the instrument power is output to the current down lead outside the measurement end of the line under test, and the voltage measurement input end is connected to the voltage down lead. line, as shown in Figure 5-3.

Figure 5-3 Positive sequence capacitance test wiring and opposite end operation diagram

3. Zero sequence capacitance test wiring and opposite end operation

Before performing the zero-sequence capacitance test, the induced voltage of the line must be measured. If the induced voltage of any phase on the three-phase line exceeds 100V, the anti-interference device equipped with the instrument must be connected between UA, UB, UC and N on the panel. space, as shown in Figure 5-4

Figure 5-4 Wiring diagram after zero sequence capacitance test and anti-interference device installed

In the zero sequence capacitance (zero sequence open circuit) test, the instrument signal lead is consistent with the positive sequence impedance test wiring. The test signal connection mode is switched through the control loop inside the instrument. The actual test wiring is as shown in Figure 5-5.

Figure 5-5 Schematic diagram of zero sequence capacitance test wiring

4. Positive sequence impedance test wiring and opposite end operation

When performing a positive sequence impedance test, short-circuit the opposite end and then connect it to ground, as shown in Figure 5-6.

Figure 5-6 Positive sequence impedance test wiring and opposite end operation diagram

  5. Zero sequence impedance test wiring and opposite end operation

When testing zero sequence impedance (zero sequence short circuit), short-circuit the opposite end line and reliably connect it to the earth, as shown in Figure 5-7.

Figure 5-7 Zero sequence impedance test wiring diagram

6. Mutual inductance test wiring and peer operation

When testing the mutual inductance between two transmission lines, the three phases of the measuring end and the opposite end of the line under test are short-circuited respectively, and the opposite end is connected to the earth. Connect the instrument output A and the voltage measurement terminal UA to the line 1 and line 2 under test respectively. The test lead is offline, as shown in Figure 5-8

Figure 5-8 Mutual inductance test wiring diagram

7. Coupling capacitor test wiring and peer operation

When testing the coupling capacitance between two lines, the three phases of the measuring end and the opposite end of the lines 1 and 2 under test are short-circuited respectively. The opposite ends are not grounded. The current lead A of the line 1 under test is connected to the output end of the instrument. The voltage The down lead UA is connected to the voltage measurement terminal, the first end of the line 2 under test is connected to UH, and the N end is connected to the earth, as shown in Figure 5-9.