CN201903638U - Detection system for power frequency line parameter tester based on virtual vector impedance method - Google Patents

Abstract

The utility model provides a power frequency line parameter tester verification device based on the "virtual complex impedance method", which is characterized in that it includes: a control module, three IV conversion modules, three virtual complex impedance modules and three voltage The output module and the verification device are designed according to the three-phase circuit. An IV conversion module, a virtual complex impedance module and a voltage output module form a circuit. The control module is connected to the three virtual complex impedance modules respectively. The value of each impedance component is controlled by module to configure. The utility model can comprehensively verify the zero-sequence capacitance, positive-sequence capacitance, zero-sequence impedance, and positive-sequence impedance measurement functions of the industrial frequency line parameter tester, and has higher accuracy and value coverage compared with the traditional "physical impedance method". The range is wider and the value adjustment step is finer.

Description

Verification device for power frequency line parameter tester based on "virtual complex impedance method"

technical field

The utility model relates to a verification device for a power frequency line parameter tester, which belongs to the field of calibration, verification and detection of electric power testing instruments.

Background technique

In order to measure the power frequency line parameters of the transmission line, many power test instrument manufacturers have developed power frequency line parameter testers. In the daily verification work, the zero-sequence capacitance, positive-sequence capacitance, zero-sequence impedance and positive-sequence impedance measurement functions of the power frequency line parameter tester are generally verified by the metrology verification institution to judge whether the instrument is out of tolerance. However, similar to many electric power testing instruments, because the power frequency line parameter tester is highly targeted in design and has a special interface, it is difficult to trace its measurement characteristics to the superior measurement standard, so it is necessary to develop a special verification device to help the measurement. Class testing equipment to carry out verification work. The following first introduces the typical working principle of the power frequency line parameter tester (see Figure 1.1, Figure 1.2, Figure 1.3, Figure 1.4).

As shown in Figure 1.1, it is the wiring diagram for the power frequency line parameter tester to measure the "zero sequence capacitance" of the transmission line. First, the power frequency line parameter tester injects single-phase excitation power into the transmission line according to the current wiring, and then The injection current I _A and the feedback voltage U _A (relative to the U _N reference point) are collected and calculated, and the "zero-sequence capacitance" C ₀ is calculated according to the relational formula U _A =3I _A ×(1/jωC ₀ ).

计算出“正序电容”C₁，其中，U＝(U_AB+U_BC+U_CA)/3，I＝(I_A+I_B+I_C)/3。As shown in Figure 1.2, it is the wiring diagram for the power frequency line parameter tester to measure the "positive sequence capacitance" of the transmission line. First, the power frequency line parameter tester injects three-phase excitation power into the transmission line according to the current wiring, and then The injection current I _A , I _B , I _C and the feedback voltage U _AB , U _BC , U _CA are collected and calculated, and according to the relation

The "positive sequence capacitance" C ₁ is calculated, where U=(U _AB +U _BC +U _CA )/3, I=(I _A +I _B +I _C )/3.

As shown in Figure 1.3, it is the wiring diagram for the power frequency line parameter tester to measure the "zero sequence impedance" of the transmission line. First, the power frequency line parameter tester injects single-phase excitation power into the transmission line according to the current wiring, and then The injection current I _A and the feedback voltage U _A (relative to the U _N reference point) are collected and calculated, and according to the relationship U _A =3I _A ×(jωL ₀ +R ₀ ), the zero-sequence inductance component of the "zero-sequence impedance" L ₀ and zero sequence resistance component R ₀ are calculated.

As shown in Figure 1.4, it is the wiring diagram for the power frequency line parameter tester to measure the "positive sequence impedance" of the transmission line. First, the power frequency line parameter tester injects three-phase excitation power into the transmission line according to the current wiring, and then The injection current I _A , I _B , I _C and the feedback voltage U _AB , U _BC , U _CA are collected and calculated, and according to the relation Calculate the positive sequence inductance component L ₁ and positive sequence resistance component R ₁ of the "positive sequence impedance", where U=(U _AB +U _BC +U _CA )/3, I=(I _A +I _B +I _C )/3.

As shown in Figure 1.1 to Figure 1.4, the power frequency line parameter tester mostly adopts the "four-terminal method" measurement principle. The so-called "four-terminal method" measurement principle is explained by taking Figure 1.1 as an _example . The output of the power supply excitation terminal A of the frequency line parameter tester flows back to the N terminal after passing through the zero-sequence capacitor loop of the transmission line, and the voltage signals at both ends of the zero-sequence capacitor loop of the transmission line are respectively fed back to the power frequency through the other two loops. The voltage input terminals U _A and _UN of the line parameter tester, the above measurement process adopts the "four-terminal method" measurement principle, that is: although the zero-sequence capacitance circuit of the transmission line under test is viewed as a two-port network as a whole, but The current output circuit and the voltage measurement circuit of the power frequency line parameter tester are respectively designed with mutually electrically isolated measurement terminals, that is, the current output terminals A and N, and the voltage measurement terminals U _A and U _N are two groups of mutually electrically isolated measurement circuits. This "four-terminal method" measurement principle is the necessary prerequisite for the utility model to carry out the verification work of the power frequency line parameter tester based on the "virtual complex impedance method".

According to the applicant's knowledge, at present, only a few units in China carry out verification work on power frequency line parameter testers, and the verification method adopted is also the traditional "object impedance method". Based on standard capacitance and physical standard resistance, it simulates the parameters of power frequency lines, and is used to verify the measurement functions of zero sequence capacitance, positive sequence capacitance, zero sequence impedance and positive sequence impedance of the power frequency line parameter tester (see Figure 2.1, Fig. 2.2, Figure 2.3, Figure 2.4), the main verification principle of the traditional "physical impedance method" is as follows:

As shown in Figure 2.1, it is a schematic diagram of the traditional "object impedance method" to verify the "zero sequence capacitance" measurement function of the tested power frequency line parameter tester. Take the precision capacitor C ₀ that has been traced back to the source as the physical standard, and provide it to the tested power frequency line parameter tester for measurement, and the checked power frequency line parameter tester will get the measurement result C _{0 test sample} , and can be calculated through the above process The zero-sequence capacitance measurement error C _{0 error} of the tested power frequency line parameter tester = C _{0 test product} - _{C 0} , and then the verification of the "zero sequence capacitance" measurement function of the tested power frequency line parameter tester was achieved. Purpose.

As shown in Figure 2.2, it is a schematic diagram of the traditional "object impedance method" to verify the "positive sequence capacitance" measurement function of the tested power frequency line parameter tester. Take the precision capacitor C ₁ that has been traced back to the source as the physical standard, and provide it to the tested power frequency line parameter tester for measurement. The tested power frequency line parameter tester will get the measurement result C _{1 sample} , and through the above process, it can be calculated The positive sequence capacitance measurement error C _{1 error} of the tested power frequency line parameter tester = C _{1 sample} - C ₁ , and then the "positive sequence capacitance" measurement function of the tested power frequency line parameter tester is verified. Purpose.

As shown in Figure 2.3, it is a schematic diagram of the traditional "object impedance method" for verifying the "zero sequence impedance" measurement function of the tested power frequency line parameter tester. The traditional "physical impedance method" only uses the precision resistance R ₀ that has been traced back as the physical standard, and provides it to the tested power frequency line parameter tester for measurement, and the checked power frequency line parameter tester will get the measurement result R _{0 test} Through _the above process, the zero sequence resistance measurement error R _{0 error} of the tested power frequency line parameter tester can be calculated = R _{0 test product} - R ₀ , and then the zero sequence resistance of the tested power frequency line parameter tester The purpose of the verification of the component measurement function. It should be noted that the method shown in Figure 2.3 cannot verify the zero-sequence inductance component measurement function of the tested power frequency line parameter tester.

As shown in Figure 2.4, it is a schematic diagram of the traditional "object impedance method" for verifying the "positive sequence impedance" measurement function of the tested power frequency line parameter tester. The traditional "physical impedance method" only takes the precision resistance R ₁ that has been traced back as the physical standard, and provides it to the tested power frequency line parameter tester for measurement, and the tested power frequency line parameter tester will get the measurement result R _{1 test} Through _the above process, the positive sequence resistance measurement error R _{1 error} of the tested power frequency line parameter tester can be calculated = R _{1 test product} - _{R 1} , and then the positive sequence resistance of the tested power frequency line parameter tester The purpose of the verification of the component measurement function. It should be noted that the method shown in Figure 2.4 cannot verify the positive sequence inductance component measurement function of the tested power frequency line parameter tester.

As mentioned above, the traditional "physical impedance method" cannot meet the needs of comprehensive verification of power frequency line parameter testers, mainly due to the following two aspects:

1. When carrying out the verification work of the power frequency line parameter tester through the traditional "physical impedance method", the precision resistance and precision capacitance that have been traced back to the source of the value are used as the physical standard. The main disadvantage is that the verification work requires multiple physical precision Resistors and precision capacitors are used to form different standard values, so there is a large demand for the number of physical standards, so the value range of physical standards in actual verification work is difficult to meet the needs of verifying power frequency line parameter testers; The output current of the line parameter tester is large (often greater than 1A). In this case, it is necessary to select large-capacity precision resistors and precision capacitors as physical standards, and large-capacity precision resistors and precision capacitors are not easy. It is mainly reflected in the fact that the accuracy and stability of large-capacity resistors and capacitors are not easy to guarantee, so the accuracy of physical standards in actual verification work cannot be well verified for the needs of power frequency line parameter testers.

2. When verifying the "zero-sequence impedance" and "positive-sequence impedance" measurement functions of the power frequency line parameter tester through the traditional "physical impedance method" (as shown in Figure 2.3 and Figure 2.4), often only the measured The zero-sequence resistance component and positive-sequence resistance component measurement function of the power frequency line parameter tester is verified, but the zero-sequence inductance component and positive-sequence inductance component are not verified. The main reason is that if the verification work of zero-sequence inductance and positive-sequence inductance component measurement function is further carried out, according to the traditional design idea of "physical impedance method", it is necessary to add precision inductance that has been traced back to the source as the physical standard, while large-capacity Compared with physical precision resistors and physical precision capacitors, it is technically more difficult to design physical precision inductors. Not only is the value coverage difficult to meet the needs of verifying power frequency line parameter testers, but also its accuracy, stability Compared with precision resistors and precision capacitors, the performance is more difficult to guarantee.

In view of this, it is necessary to provide a new verification device for power frequency line parameter testers based on the "virtual complex impedance method" to overcome the above problems.

Contents of the invention

The technical problem to be solved by the utility model is: aiming at the deficiency of the traditional "object impedance method", that is, based on this method, the measurement function of the zero-sequence inductance component and the positive-sequence inductance component of the power frequency line parameter tester cannot be verified, and at the same time In the case of low accuracy and narrow value range, based on the "four-terminal method" measurement principle of the power frequency line parameter tester, the design idea of "virtual complex impedance method" is proposed and realized. The utility model can effectively solve the traditional The deficiency of the "object impedance method".

The technical scheme adopted by the utility model is: a verification device of a power frequency line parameter tester based on the "virtual complex impedance method", which is characterized in that it includes: a control module, three IV conversion modules, three virtual complex Impedance module and three voltage output modules, the verification device is designed according to the three-phase circuit, an IV conversion module, a virtual complex impedance module and a voltage output module form a circuit, the control module is connected to the three virtual complex impedance modules, each impedance The value of the component is configured by the control module, and the current output terminals A, B, C, N of the tested power frequency line parameter tester are respectively connected to the current input terminals A _in , B _in , C _in , N of the verification device, and are controlled by The voltage input terminals U _A , _UB , _UC , _UN of the power frequency line parameter tester are respectively connected to the voltage output terminals U _Aout , U _Bout , U _Cout , _UN of the verification device.

The verification device for a power frequency line parameter tester as described above is characterized in that: the control module includes a digital control device.

The above-mentioned verification device for power frequency line parameter tester is characterized in that: the IV conversion module includes an IV conversion circuit composed of an instrument-type precision current transformer CT, a non-inductive precision resistor R _CT , and a precision operational amplifier.

The verification device of the power frequency line parameter tester as described above is characterized in that: the virtual complex impedance module includes an inductance component generation and amplitude selection circuit, a capacitive component generation and amplitude selection circuit, a resistance component generation and amplitude selection circuit, and a resistance component generation and amplitude selection circuit. value selection circuit.

The verification device of the power frequency line parameter tester as described above is characterized in that: the voltage output module includes a voltage follower composed of a power operational amplifier and a precision boost voltage transformer PT.

The beneficial effects of the utility model are: the utility model proposes and realizes the design idea of "virtual complex impedance method", and the utility model can effectively solve the deficiency of the traditional "physical impedance method", and can not only test the power frequency line parameter tester The zero-sequence capacitance, positive-sequence capacitance, zero-sequence impedance, and positive-sequence impedance measurement functions are fully verified, and the utility model has higher accuracy, wider value coverage and value adjustment compared with the traditional "physical impedance method". The stepping is finer, which satisfies the urgent need of carrying out the verification work of power frequency line parameter testers, and plays a positive role in promoting the development of power test instruments in the direction of standardization and standardization.

Description of drawings

Figure 1.1 is a schematic diagram of the "zero-sequence capacitance" measurement performed by the power frequency line parameter tester.

Figure 1.2 is a schematic diagram of the "positive sequence capacitance" measurement performed by the power frequency line parameter tester.

Figure 1.3 is a schematic diagram of "zero-sequence impedance" measurement by a power frequency line parameter tester.

Figure 1.4 is a schematic diagram of the "positive sequence impedance" measurement performed by the power frequency line parameter tester.

Figure 2.1 is a schematic diagram of the traditional "object impedance method" for verifying the "zero sequence capacitance" measurement function of the tested power frequency line parameter tester.

Figure 2.2 is a schematic diagram of the traditional "physical impedance method" for verifying the "positive sequence capacitance" measurement function of the tested power frequency line parameter tester.

Figure 2.3 is a schematic diagram of the verification of the "zero-sequence impedance" measurement function of the tested power frequency line parameter tester by the traditional "object impedance method".

Figure 2.4 is a schematic diagram of the traditional "physical impedance method" for verifying the "positive sequence impedance" measurement function of the tested power frequency line parameter tester.

Fig. 3 is a working wiring diagram of the verification device of the power frequency line parameter tester realized based on the "virtual complex impedance method" according to the embodiment of the present invention.

Fig. 4 is an internal schematic diagram of the verification device of the power frequency line parameter tester based on the "virtual complex impedance method" of the embodiment of the present invention.

Figure 4.1 is a schematic diagram of the control module in Figure 4.

Figure 4.2 is a schematic diagram of the A-phase loop I-V conversion module 2a in Figure 4 .

Fig. 4.3 is a schematic diagram of the virtual complex impedance module 3a of the A-phase loop in Fig. 4 .

Fig. 4.4 is a schematic diagram of the A-phase loop voltage output module 4a in Fig. 4 .

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is described in further detail.

Marks in the figure: 1-control module, 2a-A phase circuit I-V conversion module, 2b-B phase circuit I-V conversion module, 2c-C phase circuit I-V conversion module, 3a-A phase circuit virtual complex impedance module, 3b-B Phase loop virtual complex impedance module, 3c-C phase loop virtual complex impedance module, 4a-A phase loop voltage output module, 4b-B phase loop voltage output module, 4c-B phase loop voltage output module, CT-instrument type precision current Transformer, PT-Precision Boost Voltage Transformer

Referring to Fig. 3, it is the working wiring diagram of the verification device of the power frequency line parameter tester realized based on the "virtual complex impedance method" according to the embodiment of the present invention. Its working principle is: during the verification process, the current output terminals A, B, C, N of the power frequency line parameter tester to be tested are respectively connected to the current input terminals A _in , B _in , C _in , N of the utility model Connect the voltage input terminals U _A , _UB , U _C , _UN of the power frequency line parameter tester to be tested with the voltage output terminals U _Aout , U _Bout , U _Cout , _UN of the present invention respectively. The main working methods are as follows:

When verifying the "zero-sequence capacitance" measurement function of the power frequency line parameter tester, the utility model receives the current signal I _A from the tested power frequency line parameter tester, and according to the relation U _A =3I _A ×(1/ jωC ₀ ) A voltage signal is fed back at the U _A terminal (relative to the U _N reference point). At this time, the power frequency line parameter tester under test will measure the I _A and U _A signals and calculate the zero-sequence capacitance measurement value C _{0 of the sample} , Through the above process, the zero-sequence capacitance measurement error C _{0 error} of the tested power frequency line parameter tester can be calculated = C _{0 test product} -C ₀ , and then the "zero sequence capacitance" of the tested power frequency line parameter tester can be achieved. The purpose of the verification of the measurement function.

I＝(I_A+I_B+I_C)/3。此时被检工频线路参数测试仪将测量I_A、I_B、I_C和U_A、U_B、U_C信号并计算出正序电容测量值C_1试品，通过上述过程可计算出被检工频线路参数测试仪的正序电容测量误差C_1误差＝C_1试品-C₁，进而达到了对被检工频线路参数测试仪的“正序电容”测量功能进行检定的目的。When verifying the "positive sequence capacitance" measurement function of the power frequency line parameter tester, the utility model receives the current signals I _A , I _B , and I _C from the power frequency line parameter tester to be tested, and according to the relation Corresponding voltage signals are fed back from terminals U _A , U _B , and U _C (relative to the U _N reference point). The above relation and the feedback voltage signal satisfy U=(U _AB +U _BC +U _CA )/3,

I=(I _A +I _B +I _C )/3. At this time, the tested power frequency line parameter tester will measure I _A , I _B , I _C and U _A , U _B , U _C signals and calculate the measured value of the positive sequence capacitance C _{1 sample. Through the above process, the tested product} can be calculated The positive sequence capacitance measurement error C _{1 error} of the power frequency line parameter tester = C _{1 test product} - _{C 1} , thus achieving the purpose of verifying the "positive sequence capacitance" measurement function of the power frequency line parameter tester.

When verifying the "zero-sequence impedance" measurement function of the power frequency line parameter tester, the utility model receives the current signal I _A from the power frequency line parameter tester to be tested, and according to the relation U _A =3I _A ×(jωL ₀ +R ₀ ) The voltage signal is fed back at the U _A terminal (relative to the U _N reference point). At this time, the tested power frequency line parameter tester will measure the I _A and U _A signals and calculate the zero-sequence resistance component measurement value R _{0 test Product} and zero-sequence inductance component measurement value L _{0 test product} , through the above process, the zero-sequence resistance measurement error R _{0 error} of the tested power frequency line parameter tester can be calculated = R _{0 test product} -R ₀ and zero-sequence inductance measurement error L _{0 error} = L _{0 sample} - L ₀ , and then achieve the purpose of verifying the "zero-sequence impedance" measurement function (including zero-sequence resistance component and zero-sequence inductance component) of the tested power frequency line parameter tester.

When verifying the "positive sequence impedance" measurement function of the power frequency line parameter tester, the utility model receives the current signal I _A from the power frequency line parameter tester to be tested, and according to the relation U _A =3I _A ×(jωL ₀ +R ₀ ) The voltage signal is fed back at the U _A terminal (relative to the U _N reference point). At this time, the tested power frequency line parameter tester will measure the I _A and U _A signals and calculate the zero-sequence resistance component measurement value R _{0 test Product} and zero-sequence inductance component measurement value L _{0 test product} , through the above process, the zero-sequence resistance measurement error R _{0 error} of the tested power frequency line parameter tester can be calculated = R _{0 test product} -R ₀ and zero-sequence inductance measurement error L _{0 error} = L _{0 sample} - L ₀ , and then achieve the purpose of verifying the "positive sequence impedance" measurement function (including positive sequence resistance component and positive sequence inductance component) of the tested power frequency line parameter tester.

Referring to FIG. 4 , it is an internal schematic diagram of the verification device of a power frequency line parameter tester based on the "virtual complex impedance method" of the embodiment of the present invention. The utility model is designed according to a three-phase circuit, and the working principle of each phase circuit is the same (the working principle is explained below with the A-phase circuit as an example):

In the A-phase circuit, the utility model receives the input current signal I _A of the tested industrial frequency line parameter tester through the input terminal A _in , and the signal first passes through the "IV conversion module" 2a and outputs the voltage signal u _a1 , the voltage signal u _a1 satisfies the relational expression u _a1 =k _CT ×Ia, where k _CT is the fixed proportional coefficient of the instrument-type precision current transformer CT in this module; then the voltage signal u _a1 passes through the "virtual complex impedance module" 3a and outputs the voltage signal u _a2 , the voltage signal u _a2 satisfies the relationship u _a2 =[jωk _L +(1/jωk _C )+k _R ]×u _a1 , where k _L , k _C , and k _R are adjustable proportional coefficients, which are determined by The A-phase loop control signal sig-a from the "control module 1" is controlled separately; then the voltage signal u _a2 is amplified through the "voltage output module" 4a to finally output the voltage signal U _Aout , and U _Aout satisfies the relation U _Aout = k _PT ×u _a2 , where k _PT is the fixed proportional coefficient of the precision step-up voltage transformer PT in this module.

Through the above loop, the generated output voltage signal U _Aout and input current signal I _A satisfy the complex impedance function relationship, that is, U _Aout =k _PT ×k _CT ×[jωk _L +(1/jωk _C )+k _R ]×I _A , where the adjustable proportional coefficient of the A-phase circuit k _A =k _PT ×k _CT ×[jωk _L +(1/jωk _C )+k _R ] is the "virtual complex impedance" of the A-phase circuit realized by the utility model, the The amplitude of "virtual complex impedance" is accurate and flexible.

In the B-phase circuit and the C-phase circuit, the working principle is exactly the same as that of the A-phase circuit. Through the above process, the utility model can simulate three-phase "virtual complex impedance", and the magnitude of each impedance component is flexibly configured by the "control module 1", with a wide setting range and high accuracy. The three-phase "virtual complex impedance" realized by the utility model can not only verify the "zero-sequence capacitance" and "positive-sequence capacitance" measurement functions of the tested power frequency line parameter tester, but also can test the The "zero sequence impedance" and "positive sequence impedance" measurement functions are fully verified.

See Figure 4.1, which is a schematic diagram of the control module 1 in Figure 4. The embodiment of the utility model takes the DSP control device TMS320F2812 as the core in this module, and the main tasks of this module include: the relevant control information (such as: selecting the function of the verification, including the zero-sequence Capacitance, positive-sequence capacitance, zero-sequence impedance, positive-sequence impedance; set specific verification parameters, including capacitance components, resistance components, and inductance components in complex impedance). After the verification personnel select the verification function and set the specific verification parameters, the DSP control device will perform corresponding calculations and generate proportional coefficient control signals sig-a, sig-b, sig-c, among which sig-a is used to control The inductance component proportional coefficient k _L , the capacitive component proportional coefficient k _C , and the resistive component proportional coefficient k _R in the “virtual complex impedance module” 2a of the A-phase circuit; sig-b is used to control the corresponding The proportional coefficient of the inductance component, the proportional coefficient of the capacitive component and the proportional coefficient of the resistive component; sig-c is used to control the proportional coefficient of the inductive component, the proportional coefficient of the capacitive component and the proportional coefficient of the resistive component in the “virtual complex impedance module” 2c of the C-phase circuit.

Refer to Figure 4.2, which is the schematic diagram of the IV conversion module 2a of the A-phase loop in Figure 4 (this figure uses the A-phase loop as an example to illustrate, and the working principles of the B-phase loop and the C-phase loop are the same). In the embodiment of the utility model, the A-phase current signal I _A generated by the tested industrial frequency line parameter tester is received through the two terminals A _in and N in the module, and the current signal I _A passes through the instrument-type precision current transformer CT, wireless The IV conversion circuit composed of the precision resistor R _CT and the precision operational amplifier OP37 outputs the voltage signal u _a1 , and the voltage signal u _a1 satisfies the relational expression u _a1 = k _CT × I _A . The principles of the "IV conversion module" 2b of the B-phase circuit and the "IV conversion module" 2c of the C-phase circuit are completely consistent with those of the A-phase circuit.

See Figure 4.3, which is the schematic diagram of the virtual complex impedance module 3a of the A-phase circuit in Figure 4 (this figure uses the A-phase circuit as an example to illustrate, and the working principles of the B-phase circuit and the C-phase circuit are the same as the A-phase circuit). The utility model embodiment mainly includes in the module: an inductance component generation and amplitude selection circuit, a capacitive component generation and amplitude selection circuit, a resistance component generation and amplitude selection circuit. The working principle of each group of loops is as follows:

Among them, in the generation of the inductance component and the amplitude selection circuit, the voltage signal u _a1 from the previous stage A-phase "IV conversion module" 2a is input to the mica precision capacitor _CL , the non-inductive precision resistor _RL and the precision operational amplifier OP37. The precision differential circuit, its output voltage signal is u _a-L1 , and u _a-L1 satisfies the relationship u _a-L1 = -jωC _L R _L ×u _a1 , the voltage signal u _a-L1 is processed by the precision digital potentiometer AD5231 Precise voltage division, the linearity can reach 0.1%. The adjustable voltage division ratio of the precision digital potentiometer AD5231 of this loop is controlled by the A-phase loop proportional coefficient control signal sig-a from the "control module" 1, and the output after voltage division The signal is u _a-L2 , and the voltage signal u _a-L2 outputs the voltage signal u _a-L3 after passing through the voltage follower composed of OP37. Since the adjustable voltage division ratio coefficient of the loop can be set arbitrarily under the action of the control signal sig-a, the relational expression u _a-L3 = -jωk _L ×u _a1 can be obtained, where k _L is the adjustable voltage division ratio of the inductance component coefficient, the proportional coefficient is related to C _L and R _L and is controlled by the proportional coefficient control signal sig-a. Since C _L and R _L are fixed values, k _L can be set arbitrarily under the control of sig-a.

Among them, in the capacitive component generation and amplitude selection circuit, the voltage signal u _a1 from the previous stage A-phase "IV conversion module" 2a is input to the mica precision capacitor C _C , non-inductive precision resistor R _C and precision operational amplifier OP37 The precision integral circuit, its output voltage is u _a-C1 , and u _a-C1 satisfies the relationship u _a-C1 =-(1/jωC _C R _C )×u _a1 , the voltage signal u _a-C1 passes through the precision digital potentiometer The precision voltage divider AD5231 is used for precision voltage division, and the linearity can reach 0.1%. The adjustable voltage division ratio of the precision digital potentiometer AD5231 in this loop is still controlled by the A-phase loop proportional coefficient control signal sig-a from the "control module" 1. The output signal after voltage is u _a-C2 , and the voltage signal u _a-C2 outputs voltage signal u _a-C3 after passing through the voltage follower based on OP37. Since the adjustable proportional coefficient of the voltage division of this loop can be set arbitrarily under the action of the control signal sig-a, the relational expression u _a-C3 =-(1/jωk _C )×u _a1 can be obtained, where k _C is the adjustable capacitance component Partial pressure proportional coefficient, the proportional coefficient is related to C _C and R _C and controlled by the proportional coefficient control signal sig-a, since C _C and R _C are fixed values, k _C can be set arbitrarily under the control of sig-a.

Among them, in the resistance component generation and amplitude selection circuit, the voltage signal u _a1 from the previous stage A-phase "IV conversion module" 2a is input to the circuit composed of two equivalent non-inductive precision resistors R _R and precision operational amplifier OP37 Precision inverting amplifier circuit, its output voltage is u _a-R1 , and u _a-R1 satisfies the relationship u _a-R1 = -u _a1 , the voltage signal u _a-R1 is precisely divided by the precision digital potentiometer AD5231, linear The degree can reach 0.1%. The adjustable voltage division ratio of the precision digital potentiometer AD5231 of this loop is still controlled by the A-phase loop proportional coefficient control signal sig-a from the "control module" 1, and the output signal after voltage division is u _{a -R2} , the voltage signal u _a-R2 outputs the voltage signal u _a-R3 after passing through the voltage follower based on OP37. Since the adjustable voltage division ratio coefficient of this loop can be set arbitrarily under the action of the control signal sig-a, the relational expression u _a-R3 = -k _R ×u _a1 can be obtained, where k _R is the adjustable voltage division ratio coefficient of the resistance component , k _R can be set arbitrarily under the control of sig-a.

The 3 voltage signals u _a-L3 , u _a-C3 , u _a-R3 generated above are simultaneously input to the precision inverting addition circuit composed of 4 equivalent non-inductive precision resistors R ₂ and precision operational amplifier OP37. The output voltage is u _a2 , and u _a2 satisfies the relation:

u _a2 ＝-(u _a-L3 +u _a-C3 +u _a-R3 )＝-[-jωk _L ×u _a1 -(1/jωk _C )×u _a1 -k _R ×u _a1 ]

＝[jωk _L +(1/jωk _C )+k _R ]×u _a1 ＝[jωk _L +(1/jωk _C )+k _R ]×k _CT ×I _A

The above-mentioned process is the principle of the "virtual complex impedance module" 3a of the A-phase circuit, and the principles of the "virtual complex impedance module" 3b of the B-phase circuit and the "virtual complex impedance module" 3c of the C-phase circuit are completely consistent with the A-phase circuit.

See Figure 4.4, which is the schematic diagram of the A-phase loop voltage output module 4a in Figure 4 (this figure uses the A-phase loop as an example to illustrate, and the principle of the A-phase loop of the B-phase loop and the C-phase loop is the same). The signal u _a2 from the "virtual complex impedance module" 3a of the phase A circuit of the previous stage first passes through the voltage follower composed of the power operational amplifier OPA549 to improve the load capacity, and the output voltage is u _a3 , and the voltage signal u _a3 passes through the precision boost voltage mutual inductance The voltage amplifier PT performs voltage amplification, the voltage amplification factor of the precision voltage transformer PT is _kPT , the output voltage signal is U _AN (that is, the voltage between the voltage output terminals U _Aout and U _N of the utility model), and the voltage signal U _AN satisfies the relationship Formula: U _AN =k _PT ×u _a2 =k _PT ×k _CT ×[jωk _L +(1/jωk _C )+k _R ]×I _A .

As mentioned above, the embodiment of the utility model establishes a "virtual complex impedance" functional relationship between U _AN and I _A , that is, simulates the "virtual complex impedance" of phase A, and the "virtual complex impedance" is k _PT × k _CT ×[jωk _L +(1/jωk _C )+k _R ], where k _PT and k _CT are fixed proportional coefficients, k _L , k _C , and k _R are independently adjustable proportional coefficients under sig-a control . The above process is the principle of the A-phase circuit, and the principles of the B-phase circuit and the C-phase circuit are completely consistent with the A-phase circuit. Through the above principles, the three-phase "virtual complex impedance" is realized. The inductance component, capacitance component and resistance component of the "virtual complex impedance" can be set independently, with high accuracy and convenient operation, which can replace the traditional "physical impedance method". Carry out the verification work of the power frequency line parameter tester.

Claims (5)

1. A verification device for a power frequency line parameter tester based on the "virtual complex impedance method", characterized in that it includes: a control module, three IV conversion modules, three virtual complex impedance modules and three voltage output modules , the verification device is designed according to a three-phase circuit. An IV conversion module, a virtual complex impedance module and a voltage output module form a circuit. The control module is connected to the three virtual complex impedance modules respectively. The value of each impedance component is determined by the control module. Configuration, the current output terminals A, B, C, N of the tested power frequency line parameter tester are respectively connected to the current input terminals A _in , B in , C in , N of the verification device, and the current output terminals A, B _in , C _in , N of the tested power frequency line parameter tester The voltage input terminals U _A , U _B , U _C , and U _N are respectively connected to the voltage output terminals U _Aout , U _Bout , U _Cout , and U _N of the verification device. 2. The verification device of a power frequency line parameter tester according to claim 1, wherein the control module includes a digital control device. 3. The power frequency line parameter tester verification device according to claim 1, characterized in that: said IV transformation module includes an IV composed of an instrument-type precision current transformer CT, a non-inductive precision resistor R _CT , and a precision operational amplifier. conversion circuit. 4. The verification device of power frequency line parameter tester according to claim 1, characterized in that: the virtual complex impedance module includes a generation and amplitude selection circuit of an inductive component, a generation and amplitude selection circuit of a capacitive component, a resistance Component generation and amplitude selection circuit. 5. The verification device of power frequency line parameter tester according to claim 1, characterized in that: the voltage output module includes a voltage follower composed of a power operational amplifier and a precision boost voltage transformer PT.

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