A dual-port three-phase perturbation impedance angle measuring device and measuring method

Abstract

The application provides a dual-port three-phase disturbance impedance angle measuring device and a measuring method, and relates to the technical field of power systems.The device comprises a voltage disturbance injection module A, a current disturbance injection module B, a distributed power supply voltage and current sensing module C, a power grid voltage and current sensing module D and a relay switching module E.In the method, the triggering mode, the impedance measuring mode and the disturbance mode of the dual-port three-phase disturbance impedance angle measuring device of the distributed power supply and the power grid are set, and the PR phase-locked positive sequence impedance angle measuring method or the PR phase-locked negative sequence impedance angle measuring method is executed;thus, the impedance of the distributed power supply and the power grid in the power system is measured, and the impedance angle of the distributed power supply and the power grid is measured, the switching of the voltage disturbance mode and the current disturbance mode is realized.When the impedance to be measured is small, the voltage disturbance injection for measurement can obtain a higher signal-to-noise ratio;when the impedance to be measured is large, the current disturbance injection for measurement can obtain a higher signal-to-noise ratio.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power system, and particularly relates to a dual-port three-phase disturbance impedance angle measuring device and a measuring method. BACKGROUND

[0002] Currently, there are three stability analysis and determination methods for power angle stability, voltage stability and frequency stability in the power system, but with the gradual access of distributed power to the power grid and the power electronicization of the power grid, a subsynchronous oscillation phenomenon appears, and the existing stability analysis method cannot completely explain this phenomenon, so the impedance angle stability of the power system is proposed. In order to analyze the impedance angle of the power system and the distributed power generation equipment, a device capable of measuring the impedance angle is necessary. SUMMARY

[0003] In view of the deficiencies of the prior art, the present application provides a dual-port three-phase disturbance impedance angle measuring device and a measuring method for distributed power and power grid, which solves the problem of measuring the impedance angle of the distributed power and the power grid.

[0004] In order to solve the above technical problems, the present application adopts the following technical solutions:

[0005] A dual-port three-phase disturbance impedance angle measuring device for distributed power and power grid, comprising: a voltage disturbance injection module A, a current disturbance injection module B, a distributed power voltage and current sensing module C, a power grid voltage and current sensing module D and a relay switching module E.

[0006] The voltage disturbance injection module A is a voltage source, having an A1 port outputting a voltage signal with an amplitude of Um.

[0007] The current disturbance injection module B is a current source, having a B1 port outputting a current signal with an amplitude of Im.

[0008] The distributed power voltage and current sensing module C is a voltage and current sensor, having a C1 port and a C2 port, for measuring three-phase line voltages U1 AB , U1 BC and U1 CA , the sampling values of which are output from the C1 port; and three-phase phase currents I1 AB , I1 BC and I1 CA , the sampling values of which are output from the C2 port, wherein the three-phase phase voltages are calculated from the three-phase line voltages, i.e.

[0009] The power grid voltage and current sensing module D has a D1 port and a D2 port, for measuring three-phase line voltages U2 AB , U2 BC and U2CA , whose sampling value is output from the D1 port; and three-phase phase currents I2 AB , I2 BC , and I2 CA , whose sampling value is output from the D2 port, wherein the three-phase phase voltages are calculated from the three-phase line voltages, i.e.

[0010] The relay switching module E has an E1 port, an E2 port, an E3 port, an E4 port, and a bus, wherein the E1 port, the E2 port, the E3 port, and the E4 port are all connected to the bus through relays; the voltage disturbance is connected in series to the bus from the E3 port, and the current disturbance is connected in parallel to the bus from the E4 port;

[0011] The A1 port of the voltage disturbance injection module A is connected to the E3 port of the relay switching module E, the B1 port of the current disturbance injection module B is connected to the E4 port of the relay switching module E, the C1 port of the distributed power supply voltage and current sensing module C is an external port connected to a distributed power supply, the C2 port of the distributed power supply voltage and current sensing module C is connected to the E1 port of the relay switching module E, the D1 port of the grid voltage and current sensing module D is an external port connected to a grid, and the D2 port of the grid voltage and current sensing module D is connected to the E2 port of the relay switching module E;

[0012] A distributed power supply and grid dual-port three-phase disturbance impedance angle measurement method is realized based on the foregoing distributed power supply and grid dual-port three-phase disturbance impedance angle measurement device, and includes the following steps:

[0013] Step 1: Set the trigger mode, impedance measurement mode, and disturbance mode of the distributed power supply and grid dual-port three-phase disturbance impedance angle measurement device, set the sweep frequency range, and let the initial frequency be F0, the sweep frequency increment be ΔF, and the maximum frequency be Fmax, wherein ΔF = (Fmax-F0) / n, n is the number of sweep frequencies, F(i) is the frequency at the i-th sweep frequency, i is an integer from 1 to n, and F(1) = F0; determine the disturbance mode, and if it is a voltage disturbance mode, execute step 2, or if it is a current disturbance mode, execute step 9;

[0014] Step 2: Connect the E3 port of the relay switching module E in series to the bus, disconnect the E4 port from the bus, and execute step 3;

[0015] Step 3: Determine the impedance measurement mode, and if it is a positive sequence impedance measurement mode or a positive and negative sequence impedance measurement mode, execute step 4, or if it is a negative sequence impedance measurement mode, execute step 6;

[0016] Step 4: The voltage disturbance injection module A outputs positive sequence three-phase sinusoidal wave with frequency F(i) and voltage amplitude Um, and step 5 is executed;

[0017] Step 5: The PR phase-locked positive sequence impedance angle measurement method is executed; if it is the positive and negative sequence impedance measurement mode, step 6 is executed, and if it is the positive sequence impedance measurement mode, step 8 is executed;

[0018] Step 6: The voltage disturbance injection module A outputs negative sequence three-phase sinusoidal wave with frequency F(i) and voltage amplitude Um, and step 7 is executed;

[0019] Step 7: The PR phase-locked negative sequence impedance angle measurement method is executed; step 8 is executed;

[0020] Step 8: If the current frequency is equal to Fmax, the measurement is ended; if F(i) < Fmax, F(i+1) is set as F(i) plus ΔF, i.e. F(i+1) = F(i) + ΔF, and step 2 is executed;

[0021] Step 9: The relay switching module E is connected in parallel to the bus through the E4 port, and the E3 port is disconnected from the bus, and step 10 is executed;

[0022] Step 10: The measurement mode is judged; if it is the positive sequence impedance measurement mode or the positive and negative sequence impedance measurement mode, step 11 is executed, and if it is the negative sequence impedance measurement mode, step 13 is executed;

[0023] Step 11: The current disturbance injection module B outputs positive sequence three-phase sinusoidal wave with frequency F(i) and current amplitude Im, and step 14 is executed;

[0024] Step 14: The PR phase-locked positive sequence impedance angle measurement method is executed; if it is the positive and negative sequence impedance measurement mode, step 13 is executed, and if it is the positive sequence impedance measurement mode, step 15 is executed;

[0025] Step 13: The current disturbance injection module B outputs negative sequence three-phase sinusoidal wave with frequency F(i) and current amplitude Im, and step 14 is executed;

[0026] Step 14: The PR phase-locked negative sequence impedance angle measurement method is executed; step 15 is executed;

[0027] Step 15: If the current frequency is equal to Fmax, the measurement is ended; if F(i) < Fmax, F(i+1) is set as F(i) plus ΔF, i.e. F(i+1) = F(i) + ΔF, and step 10 is executed;

[0028] The triggering mode in step 1 includes periodic triggering and event triggering, wherein the periodic triggering is repeatedly measuring at intervals of time Tt, that is, steps 1 to the end are executed after each running of Tt; the event triggering is executing steps 1 to the end after receiving a triggering instruction;

[0029] The impedance measurement mode includes positive sequence impedance measurement mode, negative sequence impedance measurement mode and positive and negative sequence impedance measurement mode, that is, measuring the positive sequence impedance of the system, measuring the negative sequence impedance of the system, and measuring the positive sequence impedance and the negative sequence impedance of the system;

[0030] The disturbance mode includes voltage disturbance and current disturbance, that is, measuring the system impedance by injecting voltage disturbance and current disturbance respectively

[0031] The PR phase-locked positive sequence impedance angle measurement method specifically is that the distributed power voltage and current sensing module C measures the line voltage and phase current at port C1 in the tth period every T sampling period, calculates the phase voltages U1a, U1b and U1c from the line voltage, and separates the voltage and current components with a frequency of F(i), that is, U1a(F(i), t), U1b(F(i), t), U1c(F(i), t) and I1a(F(i), t), I1b(F(i), t), I1c(F(i), t); the grid voltage and current sensing module D measures the voltage and current at port D1 every T sampling period, and separates the voltage and current components with a frequency of F(i), that is, U2a(F(i), t), U2b(F(i), t), U2c(F(i), t) and I2a(F(i), t), I2b(F(i), t), I2c(F(i), t); every sampling period T, t is increased by 1 until t≥1 / (T×F(i));

[0032] The three-phase voltage and three-phase current are separated into positive and negative sequences to obtain positive sequence voltages U1p(F(i), t)=U1a(F(i), t)+a×U1b(F(i), t)+a 2 ×U1c(F(i), t), U2p(F(i), t)=U2a(F(i), t)+a×U2b(F(i), t)+a 2 ×U2c(F(i), t) and positive sequence currents I1p(F(i), t)=I1a(F(i), t)+a×I1b(F(i), t)+a 2 ×I1c(F(i), t), I2p(F(i), t)=I2a(F(i), t)+a×I2b(F(i), t)+a 2 ×I2c(F(i), t), wherein a=e -j2π / 3 .

[0033] Define sequence YU1p(F(i),t), and let EU1p(F(i),t) be the difference between U1p(F(i),t) and YU1p(F(i),t), i.e., EU1p(F(i),t) = U1p(F(i),t) - YU1p(F(i),t); set w = 2π / F(i), YU1p(F(i),0) = 0, and YU1p(F(i),1) = 0;

[0034] Define sequence YI1p(F(i),t), and let EI1p(F(i),t) be the difference between I1p(F(i),t) and YI1p(F(i),t), i.e., EI1p(F(i),t) = I1p(F(i),t) - YI1p(F(i),t); set YI1p(F(i),0) = 0, and YI1p(F(i),1) = 0;

[0035] Define sequence YU2p(F(i),t), and let EU2p(F(i),t) be the difference between U2p(F(i),t) and YU2p(F(i),t), i.e., EU2p(F(i),t) = U2p(F(i),t) - YU2p(F(i),t); set YU2p(F(i),0) = 0, and YU2p(F(i),2) = 0;

[0036] Define sequence YI2p(F(i),t), and let EI2p(F(i),t) be the difference between I2p(F(i),t) and YI2p(F(i),t), i.e., EI2p(F(i),t) = I2p(F(i),t) - YI2p(F(i),t); set YI2p(F(i),0) = 0, and YI2p(F(i),2) = 0;

[0037] Calculate YU1p(F(i),t) = -(2T 2 w 2 -8) x YU1p(F(i),(t-1)) - (T 2 w 2 +4) x

[0038] YU1p(F(i),(t-2)) + (kp(T 2 w 2 +4) + 2krT) x EU1p(F(i),t) + kp(2T 2 w 2 -8) x

[0039] EU1p(F(i),(t-1)) + (kpT 2 w 2 +4kp - 2krT) x EU1p(F(i),(t-2))) / (T 2 w 2 +4);

[0040] Compute YIp(F(i),t) = (-(2T 2 w 2 -8) x YIp(F(i),(t-1)) - (T 2 w 2 +4) x YIp(F(i),(t-2)) + (kp(T 2 w 2 +4) + 2krT) x EIp(F(i),t) + kp(2T 2 w 2 -8) x EIp(F(i),(t-1)) +

[0041] (kpT 2 w 2 +4kp - 2krT) x EIp(F(i),(t-2)) ) / (T 2 w 2 +4).

[0042] Compute YU2p(F(i),t) = (-(2T 2 w 2 -8) x YU2p(F(i),(t-1)) - (T 2 w 2 +4) x

[0043] YU2p(F(i),(t-2)) + (kp(T 2 w 2 +4) + 2krT) x EU2p(F(i),t) + kp(2T 2 w 2 -8) x

[0044] EU2p(F(i),(t-1)) + (kpT 2 w 2 +4kp - 2krT) x EU2p(F(i),(t-2)) ) / (T 2 w 2 +4).

[0045] Compute YI2p(F(i),t) = (-(2T 2 w 2 -8) x YI2p(F(i),(t-1)) - (T 2 w 2 +4) x YI2p(F(i),(t-2)) + (kp(T 2 w 2 +4) + 2krT) x EI2p(F(i),t) + kp(2T 2 w 2-8) x EI2p(F(i), (t-1)) + 4) x EI2p(F(i), (t-2))) / (T

[0046] (kpT 2 w 2 +4kp-2krT) x EI2p(F(i), (t-2))) / (T 2 w 2 +4);

[0047] Calculate DU1p(F(i), t) = YU1p(F(i), t) - YU1p(F(i), (t-1)), if DU1p(F(i), t) x

[0048] DU1p(F(i), t) = -1, record the period t as t1; calculate DI1p(F(i), t) = YI1p(F(i), t) - YI1p(F(i), (t-1)), if DI1p(F(i), t) x DI1p(F(i), t) = -1, record the period t as t2;

[0049] Calculate DU2p(F(i), t) = YU2p(F(i), t) - YU2p(F(i), (t-1)), if DU2p(F(i), t) x

[0050] DU2p(F(i), t) = -1, record the period t as t3; calculate DI2p(F(i), t) = YI2p(F(i), t) - YI2p(F(i), (t-1)), if DI2p(F(i), t) x DI2p(F(i), t) = -1, record the period t as t4;

[0051] Wherein, kp, kr are set constants;

[0052] Calculate the positive sequence impedance Z1p(F(i)) at the frequency F(i) at the C1 port = A1p(F(i)) ∠θ1p(F(i)); wherein, A1p(F(i)) is the ratio of the amplitude of the positive sequence voltage to the positive sequence current amplitude, i.e. A1p(F(i)) = |YU1p(F(i), t1)| /

[0053] |YI1p(F(i), t2)|; ∠θ1p(F(i)) is the phase difference between the positive sequence voltage U1p(F(i)) and the positive sequence current I1p(F(i)), i.e. ∠θ1p(F(n)) = T(t1-t2)F(i);

[0054] Calculate the positive sequence impedance Z2p(F(i)) at port D2 with frequency F(i) Z2p(F(i)) = A2p(F(i)) ∠θ2p(F(i)), wherein A2p(F(i)) is the ratio of the amplitude of the positive sequence voltage to the amplitude of the positive sequence current, i.e. A2p(F(i)) = |YU2p(F(i), t3)| / |I2p(F(i), t3)|

[0055] |YI2p(F(i), t4)|; ∠θ2p(F(i)) is the phase difference between the positive sequence voltage U2p(F(i)) and the positive sequence current I2p(F(i)), i.e. ∠θ2p(F(i)) = T(t3-t4)F(i);

[0056] The positive sequence impedance angle Zp(F(i)) = Ap(F(i)) ∠θp(F(i)) is the sum of the amplitude and phase of the impedance measured at port C1 and the impedance measured at port D1, i.e. Ap(F(i)) = A1p(F(i)) + A2p(F(i)); ∠θp(F(i)) = ∠θ1p(F(i)) + ∠θ2p(F(i));

[0057] The PR phase-locked negative sequence impedance angle measurement method is specifically as follows: The distributed power voltage and current sensing module C measures the voltage and current at port C1 in the t-th cycle every T sampling period, and separates the voltage and current components with frequency F(i), i.e. U1a(F(i), t), U1b(F(i), t), U1c(F(i), t) and I1a(F(i), t), I1b(F(i), t), I1c(F(i), t); The grid voltage and current sensing module D measures the voltage and current at port D1 in the t-th cycle every T sampling period, and separates the voltage and current components with frequency F(i), i.e. U2a(F(i), t), U2b(F(i), t), U2c(F(i), t) and I2a(F(i), t), I2b(F(i), t), I2c(F(i), t); Every sampling period T, t is increased by 1, until t ≥ 1 / (TxF(i));

[0058] The three-phase voltage and current are separated into positive and negative sequences to obtain the negative sequence voltage U1p(F(i), t) = U1a(F(i), t) + a×

[0059] U1b(F(i), t) + a 2 ×U1c(F(i), t), U2p(F(i), t) = U2a(F(i), t) + a×U2b(F(i), t) + a 2 ×

[0060] U2c(F(i), t) and the negative sequence current I1p(F(i), t) = I1a(F(i), t) + a×I1b(F(i), t) + a 2× I1c(F(i),t),

[0061] I2p(F(i),t) = I2a(F(i),t) + a x I2b(F(i),t) + a 2 x I2c(F(i),t), where a = e -j2π / 3 ;

[0062] Define sequence YU1p(F(i),t), and EU1p(F(i),t) = U1p(F(i),t) - YU1p(F(i),t) is obtained by subtracting YU1p(F(i),t) from U1p(F(i),t); set w = 2π / F(i), YU1p(F(i),0) = 0, YU1p(F(i),1) = 0;

[0063] Define sequence YI1p(F(i),t), and EI1p(F(i),t) = I1p(F(i),t) - YI1p(F(i),t) is obtained by subtracting YI1p(F(i),t) from I1p(F(i),t); set YI1p(F(i),0) = 0, YI1p(F(i),1) = 0;

[0064] Define sequence YU2p(F(i),t), and EU2p(F(i),t) = U2p(F(i),t) - YU2p(F(i),t) is obtained by subtracting YU2p(F(i),t) from U2p(F(i),t); set YU2p(F(i),0) = 0, YU2p(F(i),2) = 0;

[0065] Define sequence YI2p(F(i),t), and EI2p(F(i),t) = I2p(F(i),t) - YI2p(F(i),t) is obtained by subtracting YI2p(F(i),t) from I2p(F(i),t); set YI2p(F(i),0) = 0, YI2p(F(i),2) = 0;

[0066] Calculate YU1p(F(i),t) = (-(2T 2 w 2 -8) x YU1p(F(i),(t-1)) + (T 2 w 2 +4) x

[0067] YU1p(F(i),(t-2)) + (kp(T 2 w 2 +4) + 2krT) x EU1p(F(i),t) + kp(2T 2 w2 -8)×

[0068] EU1p(F(i),(t-1))+(kpT 2 w 2 +4kp-2krT)×EU1p(F(i),(t-2))) / (T 2 w 2 +4);

[0069] Calculate YI1p(F(i),t) = (-(2T 2 w 2 -8)×YI1p(F(i),(t-1))-(T 2 w 2 +4)×YI1p(F(i),(t-2))+(kp(T 2 w 2 +4)+2krT)×EI1p(F(i),t)+kp(2T 2 w 2 -8)×EI1p(F(i),(t-1))+

[0070] (kpT 2 w 2 +4kp-2krT)×EI1p(F(i),(t-2))) / (T 2 w 2 +4);

[0071] Calculate YU2p(F(i),t) = (-(2T 2 w 2 -8)×YU2p(F(i),(t-1))-(T 2 w 2 +4)×

[0072] YU2p(F(i),(t-2))+(kp(T 2 w 2 +4)+2krT)×EU2p(F(i),t)+kp(2T 2 w 2 -8)×

[0073] EU2p(F(i),(t-1))+(kpT 2 w 2 +4kp-2krT)×EU2p(F(i),(t-2))) / (T 2 w 2 +4);

[0074] Calculate YI2p(F(i),t) = (-(2T 2 w 2-8) x YI2p(F(i), (t-1)) - (T 2 w 2 +4) x YI2p(F(i), (t-2)) + (kp(T 2 w 2 +4) + 2krT) x EI2p(F(i), t) + kp(2T 2 w 2 -8) x EI2p(F(i), (t-1)) +

[0075] (kpT 2 w 2 +4kp - 2krT) x EI2p(F(i), (t-2))) / (T 2 w 2 +4);

[0076] Calculate DU1p(F(i), t) = YU1p(F(i), t) - YU1p(F(i), (t-1)), if DU1p(F(i), t) x

[0077] DU1p(F(i), t) = -1, record the period t as t1; calculate DI1p(F(i), t) = YI1p(F(i), t) - YI1p(F(i), (t-1)), if DI1p(F(i), t) x DI1p(F(i), t) = -1, record the period t as t2;

[0078] Calculate DU2p(F(i), t) = YU2p(F(i), t) - YU2p(F(i), (t-1)), if DU2p(F(i), t) x

[0079] DU2p(F(i), t) = -1, record the period t as t3; calculate DI2p(F(i), t) = YI2p(F(i), t) - YI2p(F(i), (t-1)), if DI2p(F(i), t) x DI2p(F(i), t) = -1, record the period t as t4;

[0080] Wherein, kp, kr are set constant;

[0081] Calculate the negative sequence impedance Z1p(F(i)) of the frequency F(i) at C1 port = A1p(F(i)) ∠ θ1p(F(i)); wherein, A1p(F(i)) is the ratio of the negative sequence voltage amplitude to the negative sequence current amplitude, i.e. A1p(F(i)) = |YU1p(F(i), t1)| /

[0082] |YI1p(F(i),t2)|; ∠θ1p(F(i)) is the phase difference between the negative sequence voltage U1p(F(i)) and the phase of the negative sequence current I1p(F(i)), that is, ∠θ1p(F(n)) = T(t1-t2)F(i);

[0083] The negative sequence impedance Z2p(F(i)) at the D2 port with the frequency F(i) is calculated, that is, Z2p(F(i)) = A2p(F(i)) ∠θ2p(F(i)); wherein, A2p(F(i)) is the ratio of the amplitude of the negative sequence voltage to the amplitude of the negative sequence current, that is, A2p(F(i)) = |YU2p(F(i),t3)| / |YI2p(F(i),t4)|

[0084] |YI2p(F(i),t4)|; ∠θ2p(F(i)) is the phase difference between the negative sequence voltage U2p(F(i)) and the phase of the negative sequence current I2p(F(i)), that is, ∠θ2p(F(i)) = T(t3-t4)F(i);

[0085] The negative sequence impedance angle Zp(F(i)) = Ap(F(i)) ∠θp(F(i)) is obtained by summing the amplitude and phase of the impedance measured at the C1 port and the impedance measured at the D1 port, that is, Ap(F(i)) = A1p(F(i))+A2p(F(i)); ∠θp(F(i)) = ∠θ1p(F(i))+ ∠θ2p(F(i)).

[0086] The beneficial effects produced by the above technical solutions are as follows:

[0087] The present application provides a kind of distributed power and grid dual-port three-phase disturbance impedance angle measuring device and measuring method, with the following beneficial effects:

[0088] 1. The distributed power and grid dual-port three-phase disturbance impedance angle measuring device provided in the present application can measure the impedance of the distributed power and the grid in the power system, and further measure the impedance angle of the distributed power and the grid, compared with the existing impedance analysis equipment which is only used for measuring passive impedance network.

[0089] 2. The distributed power and grid dual-port three-phase disturbance impedance angle measuring device provided in the present application can switch between voltage disturbance and current disturbance mode, compared with the existing impedance analysis equipment which can only satisfy single voltage disturbance injection or current disturbance injection. When the measured impedance is small, injecting voltage disturbance for measurement can obtain higher signal-to-noise ratio; when the measured impedance is large, injecting current disturbance for measurement can obtain higher signal-to-noise ratio. BRIEF DESCRIPTION OF DRAWINGS

[0090] Figure 1 The device structure schematic diagram in the specific embodiment of the present application is shown in the figure;

[0091] Figure 2 This is a schematic diagram of the voltage disturbance mode workflow in a specific embodiment of the present invention;

[0092] Figure 3 This is a schematic diagram of the current disturbance mode workflow in a specific embodiment of the present invention;

[0093] Figure 4 This is a diagram showing the internal structure of the relay switching module E in a specific embodiment of the present invention. Detailed Implementation

[0094] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0095] A distributed power source and grid two-port three-phase disturbance impedance angle measurement device, such as Figure 1 As shown, it includes: voltage disturbance injection module A, current disturbance injection module B, distributed power source voltage and current sensing module C, grid voltage and current sensing module D, and relay switching module E;

[0096] The voltage disturbance injection module A is a voltage source, with a voltage signal output with amplitude Um at port A1; such as Figure 2 As shown;

[0097] The current disturbance injection module B is a current source, with a current signal output at port B1 having an amplitude of Im; for example Figure 3 As shown;

[0098] The distributed power supply voltage and current sensing module C is a voltage and current sensor with ports C1 and C2, used to measure the three-phase line voltage U1. AB U1 BC and U1 CA Its sampled value is output from port C1; and the three-phase phase current I1 AB I1 BC and I1 CA Its sampled value is output from port C2, where the three-phase phase voltage is calculated from the three-phase line voltage, i.e.

[0099] The grid voltage and current sensing module D has ports D1 and D2 for measuring the three-phase line voltage U2. AB U2 BC and U2 CA Its sampled value is output from port D1; and the three-phase phase current I2 AB I2 BC and I2 CA Its sampled value is output from port D2, where the three-phase phase voltage is calculated from the three-phase line voltage, i.e.

[0100] The relay switching module E has an E1 port, an E2 port, an E3 port, an E4 port and a bus, as shown in the figure; wherein the E1 port, the E2 port, the E3 port and the E4 port are connected to the bus through the relay; the voltage disturbance is connected in series to the bus from the E3 port and the current disturbance is connected in parallel to the bus from the E4 port; Figure 4

[0101] The A1 port of the voltage disturbance injection module A is connected to the E3 port of the relay switching module E, the B1 port of the current disturbance injection module B is connected to the E4 port of the relay switching module E, the C1 port of the distributed power voltage and current sensing module C is an external port connected to the distributed power, the C2 port of the distributed power voltage and current sensing module C is connected to the E1 port of the relay switching module E, the D1 port of the grid voltage and current sensing module D is an external port connected to the grid, and the D2 port of the grid voltage and current sensing module D is connected to the E2 port of the relay switching module E;

[0102] A distributed power and grid dual-port three-phase disturbance impedance angle measurement method is realized based on the foregoing distributed power and grid dual-port three-phase disturbance impedance angle measurement device, and includes the following steps:

[0103] Step 1: Set the trigger mode, impedance measurement mode and disturbance mode of the distributed power and grid dual-port three-phase disturbance impedance angle measurement device, set the sweep frequency range, let the initial frequency be F0, and the sweep frequency increment be ΔF, and the maximum frequency be Fmax, wherein ΔF=(Fmax-F0) / n, n is the number of sweep frequencies; F(i) is the frequency at the i-th sweep frequency, i is an integer from 1 to n, F(1)=F0; judge the disturbance mode, if it is a voltage disturbance mode, execute step 2, if it is a current disturbance mode, execute step 9;

[0104] Step 2: connect the E3 port of the relay switching module E in series to the bus, disconnect the E4 port from the bus, and execute step 3;

[0105] Step 3: judge the impedance measurement mode, if it is a positive sequence impedance measurement mode or a positive and negative sequence impedance measurement mode, execute step 4, if it is a negative sequence impedance measurement mode, execute step 6;

[0106] Step 4: the voltage disturbance injection module A outputs a positive sequence three-phase sinusoidal wave with a frequency of F(i) and a voltage amplitude of Um, and executes step 5;

[0107] Step 5: execute the PR phase-locked positive sequence impedance angle measurement method; if it is a positive and negative sequence impedance measurement mode, execute step 6, if it is a positive sequence impedance measurement mode, execute step 8;​

[0108] Step 6: The voltage disturbance injection module A outputs negative sequence three-phase sinusoidal wave with frequency F(i) and voltage amplitude Um, and step 7 is executed;

[0109] Step 7: The PR phase-locked negative sequence impedance angle measurement method is executed; step 8 is executed;

[0110] Step 8: If the current frequency is equal to Fmax, the measurement is ended; if F(i) < Fmax, F(i+1) is set as F(i) plus ΔF, i.e. F(i+1) = F(i) + ΔF, and step 2 is executed;

[0111] Step 9: The relay switching module E is connected in parallel to the bus at the E4 port, and the E3 port is disconnected from the bus, and step 10 is executed;

[0112] Step 10: The measurement mode is judged; if it is the positive sequence impedance measurement mode or the positive and negative sequence impedance measurement mode, step 11 is executed; if it is the negative sequence impedance measurement mode, step 13 is executed;

[0113] Step 11: The current disturbance injection module B outputs positive sequence three-phase sinusoidal wave with frequency F(i) and current amplitude Im, and step 14 is executed;

[0114] Step 14: The PR phase-locked positive sequence impedance angle measurement method is executed; if it is the positive and negative sequence impedance measurement mode, step 13 is executed; if it is the positive sequence impedance measurement mode, step 15 is executed;

[0115] Step 13: The current disturbance injection module B outputs negative sequence three-phase sinusoidal wave with frequency F(i) and current amplitude Im, and step 14 is executed;

[0116] Step 14: The PR phase-locked negative sequence impedance angle measurement method is executed; step 15 is executed;

[0117] Step 15: If the current frequency is equal to Fmax, the measurement is ended; if F(i) < Fmax, F(i+1) is set as F(i) plus ΔF, i.e. F(i+1) = F(i) + ΔF, and step 10 is executed;

[0118] The triggering mode in step 1 includes periodic triggering and event triggering, wherein the periodic triggering is repeatedly measuring at intervals of time Tt, that is, steps 1 to the end are executed after running for Tt time; the unit of time Tt is second, Tt can be a fixed constant or a periodic function of time, for example, Tt = sin(m x t), wherein m is a constant and t is the number of sampling periods; the event triggering is executing steps 1 to the end after receiving a triggering instruction; wherein the triggering instruction can be a level signal, a communication instruction, or a sampling value of the distributed power voltage and current sensing module C or the grid voltage and current sensing module D, that is, when the sampling values of the distributed power voltage and current sensing module C and the grid voltage and current sensing module D do not satisfy U min <U, and U max >U, I min <I, and I max >I, wherein U min , U max , I min , I max are the maximum and minimum values of the set voltage and current, U can be U1 AB , U1 BC , U1 CA , U2 AB , U2 BC and U2 CA , and I can be I1 AB , I1 BC , I1 CA , I2 AB , I2 BC and I2 CA , the triggering event is executed, and steps 1 to the end are executed;

[0119] The impedance measurement mode includes positive sequence impedance measurement mode, negative sequence impedance measurement mode, and positive and negative sequence impedance measurement mode, that is, measuring the positive sequence impedance of the system, measuring the negative sequence impedance of the system, and measuring the positive sequence impedance and the negative sequence impedance of the system.

[0120] The disturbance mode includes voltage disturbance and current disturbance, that is, measuring the system impedance by injecting voltage disturbance and current disturbance, respectively

[0121] The PR phase-locked positive sequence impedance angle measurement method is specifically: the distributed power voltage and current sensing module C measures the line voltage and phase current at port C1 every T sampling period, calculates the phase voltage U1a, U1b, U1c from the line voltage, and separates the voltage and current components with a frequency of F(i), that is, U1a(F(i), t), U1b(F(i), t), U1c(F(i), t) and I1a(F(i), t), I1b(F(i), t), I1c(F(i), t); the grid voltage and current sensing module D measures the voltage and current at port D1 every T sampling period, and separates the voltage and current components with a frequency of F(i), that is, U2a(F(i), t), U2b(F(i), t), U2c(F(i), t) and I2a(F(i), t), I2b(F(i), t), I2c(F(i), t); wherein, the unit of T is second; every sampling period T, t is increased by 1, until t≥1 / (T×F(i));

[0122] The three-phase voltage and three-phase current are separated into positive and negative sequences to obtain positive sequence voltage U1p(F(i), t) = U1a(F(i), t) + a×U1b(F(i), t) + a 2 ×U1c(F(i), t), U2p(F(i), t) = U2a(F(i), t) + a×U2b(F(i), t) + a 2 ×U2c(F(i), t) and positive sequence current I1p(F(i), t) = I1a(F(i), t) + a×I1b(F(i), t) + a 2 ×I1c(F(i), t), I2p(F(i), t) = I2a(F(i), t) + a×I2b(F(i), t) + a 2 ×I2c(F(i), t), wherein, a = e -j2π / 3 .

[0123] The sequence YU1p(F(i), t) is defined, and the difference between U1p(F(i), t) and YU1p(F(i), t) is EU1p(F(i), t), that is, EU1p(F(i), t) = U1p(F(i), t) - YU1p(F(i), t); set w = 2π / F(i), YU1p(F(i), 0) = 0, YU1p(F(i), 1) = 0;

[0124] Define sequence YI1p(F(i),t), and calculate EI1p(F(i),t) by subtracting YI1p(F(i),t) from I1p(F(i),t), i.e., EI1p(F(i),t) = I1p(F(i),t) - YI1p(F(i),t); set YI1p(F(i),0) = 0, YI1p(F(i),1) = 0;

[0125] Define sequence YU2p(F(i),t), and calculate EU2p(F(i),t) by subtracting YU2p(F(i),t) from U2p(F(i),t), i.e., EU2p(F(i),t) = U2p(F(i),t) - YU2p(F(i),t); set YU2p(F(i),0) = 0, YU2p(F(i),2) = 0;

[0126] Define sequence YI2p(F(i),t), and calculate EI2p(F(i),t) by subtracting YI2p(F(i),t) from I2p(F(i),t), i.e., EI2p(F(i),t) = I2p(F(i),t) - YI2p(F(i),t); set YI2p(F(i),0) = 0, YI2p(F(i),2) = 0;

[0127] Calculate YU1p(F(i),t) = (-(2T 2 w 2 -8) × YU1p(F(i),(t-1)) - (T 2 w 2 +4) ×

[0128] YU1p(F(i),(t-2)) + (kp(T 2 w 2 +4) + 2krT) × EU1p(F(i),t) + kp(2T 2 w 2 -8) ×

[0129] EU1p(F(i),(t-1)) + (kpT 2 w 2 +4kp - 2krT) × EU1p(F(i),(t-2))) / (T 2 w 2 +4);

[0130] Calculate YI1p(F(i),t) = (-(2T 2 w 2 -8) × YI1p(F(i),(t-1)) - (T 2 w 2 +4) × YI1p(F(i),(t-2)) + (kp(T 2 w2 + 4) + 2krT) x EIlp(F(i),t) + kp(2T 2 w 2 - 8) x EIlp(F(i), (t-1)) + (kpT

[0131] (kpT 2 w 2 + 4kp - 2krT) x EIlp(F(i), (t-2)) ) / (T 2 w 2 + 4);

[0132] Calculate YUl p(F(i),t) = (-(2T 2 w 2 - 8) x YUl p(F(i), (t-1)) - (kpT 2 w 2 + 4) x

[0133] YUl p(F(i), (t-2)) + (kp(T 2 w 2 + 4) + 2krT) x EUl p(F(i),t) + kp(2T 2 w 2 - 8) x

[0134] EUl p(F(i), (t-1)) + (kpT 2 w 2 + 4kp - 2krT) x EUl p(F(i), (t-2)) ) / (T 2 w 2 + 4);

[0135] Calculate YI2p(F(i),t) = (-(2T 2 w 2 - 8) x YI2p(F(i), (t-1)) - (kpT 2 w 2 + 4) x YI2p(F(i), (t-2)) + (kp(T 2 w 2 + 4) + 2krT) x EI2p(F(i),t) + kp(2T 2 w 2 - 8) x EI2p(F(i), (t-1)) +

[0136] (kpT 2 w 2 + 4kp - 2krT) x EI2p(F(i), (t-2)) ) / (T 2 w 2 + 4);

[0137] Calculate DU1p(F(i),t) = YU1p(F(i),t) - YU1p(F(i), (t-1)), if DU1p(F(i),t) x

[0138] DU1p(F(i),t) = -1, record the period t as t1; calculate DI1p(F(i),t) = YI1p(F(i),t) - YI1p(F(i), (t-1)), if DI1p(F(i),t) x DI1p(F(i),t) = -1, record the period t as t2;

[0139] Calculate DU2p(F(i),t) = YU2p(F(i),t) - YU2p(F(i), (t-1)), if DU2p(F(i),t) x

[0140] DU2p(F(i),t) = -1, record the period t as t3; calculate DI2p(F(i),t) = YI2p(F(i),t) - YI2p(F(i), (t-1)), if DI2p(F(i),t) x DI2p(F(i),t) = -1, record the period t as t4;

[0141] Wherein, kp, kr are set constants;

[0142] Calculate C1 port frequency F(i) positive sequence impedance Z1p(F(i)) = A1p(F(i)) ∠θ1p(F(i)); Wherein, A1p(F(i)) is the ratio of the positive sequence voltage amplitude and the positive sequence current amplitude, that is, A1p(F(i)) = |YU1p(F(i),t1)| /

[0143] |YI1p(F(i),t2)|; ∠θ1p(F(i)) is the phase difference of the positive sequence voltage U1p(F(i)) and the positive sequence current I1p(F(i)), that is, ∠θ1p(F(n)) = T(t1-t2)F(i);

[0144] Calculate D2 port frequency F(i) positive sequence impedance Z2p(F(i)) = A2p(F(i)) ∠θ2p(F(i)); Wherein, A2p(F(i)) is the ratio of the positive sequence voltage amplitude and the positive sequence current amplitude, that is, A2p(F(i)) = |YU2p(F(i),t3)| /

[0145] |YI2p(F(i),t4)|; ∠θ2p(F(i)) is the phase difference of the positive sequence voltage U2p(F(i)) and the positive sequence current I2p(F(i)), that is, ∠θ2p(F(i)) = T(t3-t4)F(i);

[0146] The positive sequence impedance angle Zp(F(i))=Ap(F(i))∠θp(F(i)) is obtained by summing the amplitude and phase of the impedance measured at the C1 port and the impedance measured at the D1 port, i.e., Ap(F(i))=A1p(F(i))+A2p(F(i)); ∠θp(F(i))=∠θ1p(F(i))+∠θ2p(F(i));

[0147] The PR phase-locked negative sequence impedance angle measurement method is specifically as follows: the distributed power voltage and current sensing module C measures the voltage and current at the port C1 in the t-th period every T sampling period, and separates the voltage and current components with a frequency of F(i), i.e., U1a(F(i), t), U1b(F(i), t), U1c(F(i), t) and I1a(F(i), t), I1b(F(i), t), I1c(F(i), t); the grid voltage and current sensing module D measures the voltage and current at the port D1 in the t-th period every T sampling period, and separates the voltage and current components with a frequency of F(i), i.e., U2a(F(i), t), U2b(F(i), t), U2c(F(i), t) and I2a(F(i), t), I2b(F(i), t), I2c(F(i), t); wherein, the unit of T is second; every sampling period T, t is increased by 1, until t≥1 / (T×F(i));

[0148] The three-phase voltage and current are separated into positive and negative sequences to obtain the negative sequence voltage U1p(F(i), t)=U1a(F(i), t)+a×

[0149] U1b(F(i), t)+a 2 ×U1c(F(i), t), U2p(F(i), t)=U2a(F(i), t)+a×U2b(F(i), t)+a 2 ×

[0150] U2c(F(i), t) and the negative sequence current I1p(F(i), t)=I1a(F(i), t)+a×I1b(F(i), t)+a 2 ×I1c(F(i), t),

[0151] I2p(F(i), t)=I2a(F(i), t)+a×I2b(F(i), t)+a 2 ×I2c(F(i), t), wherein, a=e -j2π / 3 ;

[0152] Define sequence YU1p(F(i),t), and let EU1p(F(i),t) be the difference between U1p(F(i),t) and YU1p(F(i),t), i.e., EU1p(F(i),t) = U1p(F(i),t) - YU1p(F(i),t); set w = 2π / F(i), YU1p(F(i),0) = 0, and YU1p(F(i),1) = 0;

[0153] Define sequence YI1p(F(i),t), and let EI1p(F(i),t) be the difference between I1p(F(i),t) and YI1p(F(i),t), i.e., EI1p(F(i),t) = I1p(F(i),t) - YI1p(F(i),t); set YI1p(F(i),0) = 0, and YI1p(F(i),1) = 0;

[0154] Define sequence YU2p(F(i),t), and let EU2p(F(i),t) be the difference between U2p(F(i),t) and YU2p(F(i),t), i.e., EU2p(F(i),t) = U2p(F(i),t) - YU2p(F(i),t); set YU2p(F(i),0) = 0, and YU2p(F(i),2) = 0;

[0155] Define sequence YI2p(F(i),t), and let EI2p(F(i),t) be the difference between I2p(F(i),t) and YI2p(F(i),t), i.e., EI2p(F(i),t) = I2p(F(i),t) - YI2p(F(i),t); set YI2p(F(i),0) = 0, and YI2p(F(i),2) = 0;

[0156] Calculate YU1p(F(i),t) = -(2T 2 w 2 -8) x YU1p(F(i),(t-1)) - (T 2 w 2 +4) x

[0157] YU1p(F(i),(t-2)) + (kp(T 2 w 2 +4) + 2krT) x EU1p(F(i),t) + kp(2T 2 w 2 -8) x

[0158] EU1p(F(i),(t-1)) + (kpT 2 w 2 +4kp - 2krT) x EU1p(F(i),(t-2))) / (T 2 w 2 +4);

[0159] Compute YIp(F(i),t) = (-(2T 2 w 2 -8) x YIp(F(i),(t-1)) - (T 2 w 2 +4) x YIp(F(i),(t-2)) + (kp(T 2 w 2 +4) + 2krT) x EIp(F(i),t) + kp(2T 2 w 2 -8) x EIp(F(i),(t-1)) +

[0160] (kpT 2 w 2 +4kp - 2krT) x EIp(F(i),(t-2)) ) / (T 2 w 2 +4);

[0161] Compute YU2p(F(i),t) = (-(2T 2 w 2 -8) x YU2p(F(i),(t-1)) - (T 2 w 2 +4) x

[0162] YU2p(F(i),(t-2)) + (kp(T 2 w 2 +4) + 2krT) x EU2p(F(i),t) + kp(2T 2 w 2 -8) x

[0163] EU2p(F(i),(t-1)) + (kpT 2 w 2 +4kp - 2krT) x EU2p(F(i),(t-2)) ) / (T 2 w 2 +4);

[0164] Compute YI2p(F(i),t) = (-(2T 2 w 2 -8) x YI2p(F(i),(t-1)) - (T 2 w 2 +4) x YI2p(F(i),(t-2)) + (kp(T 2 w 2 +4) + 2krT) x EI2p(F(i),t) + kp(2T 2 w 2-8) x EI2p(F(i), (t-1)) + 4) x EI2p(F(i), (t-2))) / (T

[0165] (kpT 2 w 2 +4kp-2krT) x EI2p(F(i), (t-2))) / (T 2 w 2 +4) ;

[0166] Calculate DU1p(F(i), t) = YU1p(F(i), t) - YU1p(F(i), (t-1)), if DU1p(F(i), t) x

[0167] DU1p(F(i), t) = -1, record the period t as t1; calculate DI1p(F(i), t) = YI1p(F(i), t) - YI1p(F(i), (t-1)), if DI1p(F(i), t) x DI1p(F(i), t) = -1, record the period t as t2;

[0168] Calculate DU2p(F(i), t) = YU2p(F(i), t) - YU2p(F(i), (t-1)), if DU2p(F(i), t) x

[0169] DU2p(F(i), t) = -1, record the period t as t3; calculate DI2p(F(i), t) = YI2p(F(i), t) - YI2p(F(i), (t-1)), if DI2p(F(i), t) x DI2p(F(i), t) = -1, record the period t as t4;

[0170] Wherein, kp, kr are set constants;

[0171] Calculate the negative sequence impedance Z1p(F(i)) at the frequency F(i) at the C1 port = A1p(F(i)) ∠θ1p(F(i)); wherein, A1p(F(i)) is the ratio of the amplitude of the negative sequence voltage to the negative sequence current amplitude, i.e. A1p(F(i)) = |YU1p(F(i), t1)| /

[0172] |YI1p(F(i), t2)|; ∠θ1p(F(i)) is the phase difference between the negative sequence voltage U1p(F(i)) and the negative sequence current I1p(F(i)), i.e. ∠θ1p(F(n)) = T(t1-t2)F(i);

[0173] Calculate the negative sequence impedance Z2p(F(i)) at the frequency of F(i) at the D2 port, Z2p(F(i)) = A2p(F(i)) ∠θ2p(F(i)), wherein A2p(F(i)) is the ratio of the amplitude of the negative sequence voltage to the amplitude of the negative sequence current, i.e., A2p(F(i)) = |YU2p(F(i), t3)| / |YI2p(F(i), t3)|

[0174] |YI2p(F(i),t4)|;∠θ2p(F(i)) is the phase difference between the negative sequence voltage U2p(F(i)) and the negative sequence current I2p(F(i)), i.e., ∠θ2p(F(i)) = T(t3-t4)F(i);

[0175] The negative sequence impedance angle Zp(F(i)) = Ap(F(i)) ∠θp(F(i)), which is the sum of the amplitude and phase of the impedance measured at the C1 port and the impedance measured at the D1 port, i.e., Ap(F(i)) = A1p(F(i)) + A2p(F(i)); ∠θp(F(i)) = ∠θ1p(F(i)) + ∠θ2p(F(i)).

[0176] The above description is merely preferred embodiments of the present disclosure and a description of the principles of the technology applied. It will be understood by those skilled in the art that the scope of the application involved in the embodiments of the present disclosure is not limited to the technical solutions formed by the specific combinations of the above technical features, and should also cover other technical solutions formed by any combinations of the above technical features or equivalent features without departing from the above inventive concept. For example, the above features are replaced with each other to form technical solutions with similar functions disclosed in the embodiments of the present disclosure (but not limited to).

Claims

1. A method for measuring the impedance angle of a two-port three-phase disturbance, characterized in that, It includes the following steps: Step 1: Set the triggering mode, impedance measurement mode, and disturbance mode of the dual-port three-phase disturbance impedance angle measurement device for distributed power sources and power grids. Set the frequency sweep range, with the initial frequency being F0, the frequency increment per sweep being ΔF, and the maximum frequency being Fmax, where ΔF = (Fmax - F0) / n, and n is the number of frequency sweeps; F(i) is the frequency at the i-th frequency sweep, i is an integer from 1 to n, and F(1) = F0; Determine the disturbance mode. If it is the voltage disturbance mode, execute Step 2. If it is the current disturbance mode, execute Step 9; Step 2: Connect the E3 port of the relay switching module E in series to the bus, and disconnect the E4 port from the bus, then execute Step 3; Step 3: Determine the impedance measurement mode. If it is the positive-sequence impedance measurement mode or the positive-negative sequence impedance measurement mode, execute Step 4. If it is the negative-sequence impedance measurement mode, execute Step 6; Step 4: The voltage disturbance injection module A outputs a positive-sequence three-phase sine wave with a frequency of F(i) and a voltage amplitude of Um, then execute Step 5; Step 5: Execute the PR phase-locked positive-sequence impedance angle measurement method; If it is the positive-negative sequence impedance measurement mode, execute Step 6. If it is the positive-sequence impedance measurement mode, execute Step 8; Step 6: The voltage disturbance injection module A outputs a negative-sequence three-phase sine wave with a frequency of F(i) and a voltage amplitude of Um, then execute Step 7; Step 7: Execute the PR phase-locked negative-sequence impedance angle measurement method; Execute Step 8; Step 8: If the current frequency is equal to Fmax, the measurement ends; If F(i) < Fmax, set F(i + 1) as F(i) plus ΔF, that is, F(i + 1) = F(i) + ΔF, and execute Step 2; Step 9: Connect the E4 port of the relay switching module E in parallel to the bus, and disconnect the E3 port from the bus, then execute Step 10; Step 10: Determine the measurement mode. If it is the positive-sequence impedance measurement mode or the positive-negative sequence impedance measurement mode, execute Step 11. If it is the negative-sequence impedance measurement mode, execute Step 13; Step 11: The current disturbance injection module B outputs a positive-sequence three-phase sine wave with a frequency of F(i) and a current amplitude of Im, then execute Step 14; Step 14: Execute the PR phase-locked positive-sequence impedance angle measurement method; If it is the positive-negative sequence impedance measurement mode, execute Step 13. If it is the positive-sequence impedance measurement mode, execute Step 15; Step 13: The current disturbance injection module B outputs a negative-sequence three-phase sine wave with a frequency of F(i) and a current amplitude of Im, then execute Step 14; Step 14: Execute the PR phase-locked negative-sequence impedance angle measurement method; Execute Step 15; Step 15: If the current frequency is equal to Fmax, the measurement ends; If F(i) < Fmax, set F(i + 1) as the F(i) of the previous cycle plus ΔF, that is, F(i + 1) = F(i) + ΔF, and execute Step 10; The described dual-port three-phase disturbance impedance angle measurement method is implemented through a dual-port three-phase disturbance impedance angle measurement device, which includes a voltage disturbance injection module A, a current disturbance injection module B, a distributed power source voltage and current sensing module C, a power grid voltage and current sensing module D, and a relay switching module E; The voltage disturbance injection module A is a voltage source with a voltage signal with an amplitude of Um output from port A1; The current disturbance injection module B is a current source, with a current signal with an amplitude of Im output from port B1. The distributed power supply voltage and current sensing module C is a voltage and current sensor with ports C1 and C2, used to measure the three-phase line voltage. , and Its sampled value is output from port C1; and the three-phase phase current. , and Its sampled value is output from port C2, where the three-phase phase voltage is calculated from the three-phase line voltage, i.e. , , ; The grid voltage and current sensing module D has ports D1 and D2 for measuring three-phase line voltage. , and Its sampled value is output from port D1; and the three-phase phase current. , and Its sampled value is output from port D2, where the three-phase phase voltage is calculated from the three-phase line voltage, i.e. , , ; The relay switching module E has E1 port, E2 port, E3 port, E4 port and bus. Ports E1, E2, E3 and E4 are all connected to the bus via relays. Voltage disturbances are connected to the bus in series from port E3 and current disturbances are connected to the bus in parallel from port E4.

2. The method for measuring the impedance angle of a two-port three-phase disturbance according to claim 1, characterized in that, The triggering methods described in step 1 include two types: periodic triggering and event triggering. Periodic triggering means that the measurement is repeated at time intervals Tt, that is, step 1 is executed until the end after each Tt running time. Event triggering means that step 1 is executed until the end after receiving the trigger command.

3. The method for measuring the impedance angle of a two-port three-phase disturbance according to claim 1, characterized in that, The impedance measurement modes mentioned in step 1 include three types: positive sequence impedance measurement mode, negative sequence impedance measurement mode, and positive and negative sequence impedance measurement mode, namely, measuring the positive sequence impedance of the system, measuring the negative sequence impedance of the system, and measuring the positive sequence impedance and negative sequence impedance of the system.

4. The method for measuring the impedance angle of a two-port three-phase disturbance according to claim 1, characterized in that, The disturbance modes mentioned in step 1 include two types: voltage disturbance and current disturbance. That is, the system impedance is measured by injecting voltage disturbance and current disturbance, respectively.

5. The method for measuring the impedance angle of a two-port three-phase disturbance according to claim 1, characterized in that, The PR phase-locked positive sequence impedance angle measurement method described in step 5 is as follows: the distributed power supply voltage and current sensing module C measures the line voltage and phase current at port C1 in the t-th period every T sampling period, calculates the phase voltages U1a, U1b, and U1c based on the line voltage, and separates the voltage and current components with frequency F(i), namely U1a(F(i),t), U1b(F(i),t), U1c(F(i),t) and I1a(F(i),t), I1b(F(i),t), I1c(F(i),t); The grid voltage and current sensing module D measures the voltage and current at port D1 in the t-th period every T sampling period, and separates the voltage and current components with frequency F(i), namely U2a(F(i),t), U2b(F(i),t), U2c(F(i),t) and I2a(F(i),t), I2b(F(i),t), I2c(F(i),t). Each time a sampling period T passes, t is incremented by 1 until... ; The three-phase voltages and three-phase currents are separated into positive and negative sequences to obtain the positive sequence voltage. , and positive sequence current , ,in, ; Define sequence ,Will and Doing bad ,Right now ;set up , , ; Define sequence ,Will and Doing bad ,Right now ;set up , ; Define sequence ,Will and Doing bad ,Right now ;set up , ; Define sequence ,Will and Doing bad ,Right now ;set up , ; Calculate YU1p(F(i),t)=(-(2T 2 w 2 -8)×YU1p(F(i),(t - 1))-(T 2 w 2 +4)×YU1p(F(i),(t - 2))+(kp(T 2 w 2 +4)+2krT)×EU1p(F(i),t)+kp(2T 2 w 2 -8)×EU1p(F(i),(t - 1))+(kpT 2 w 2 +4kp - 2krT)×EU1p(F(i),(t - 2))) / (T 2 w 2 +4); Calculate YI1p(F(i),t)=(-(2T 2 w 2 -8)×YI1p(F(i),(t - 1))-(T 2 w 2 +4)×YI1p(F(i),(t - 2))+(kp(T 2 w 2 +4)+2krT)×EI1p(F(i),t)+kp(2T 2 w 2 -8)×EI1p(F(i),(t - 1))+(kpT 2 w 2 +4kp - 2krT)×EI1p(F(i),(t - 2))) / (T 2 w 2 +4); Calculate YU2p(F(i),t)=(-(2T 2 w 2 -8)×YU2p(F(i),(t - 1))-(T 2 w 2 +4)×YU2p(F(i),(t - 2))+(kp(T 2 w 2 +4)+2krT)×EU2p(F(i),t)+kp(2T 2 w 2 -8)×EU2p(F(i),(t - 1))+(kpT 2 w 2 +4kp - 2krT)×EU2p(F(i),(t - 2))) / (T 2 w 2 +4); Calculate YI2p(F(i),t)=(-(2T 2 w 2 -8)×YI2p(F(i),(t - 1))-(T 2 w 2 +4)×YI2p(F(i),(t - 2))+(kp(T 2 w 2 +4)+2krT)×EI2p(F(i),t)+kp(2T 2 w 2 -8)×EI2p(F(i),(t - 1))+(kpT 2 w 2 +4kp - 2krT)×EI2p(F(i),(t - 2))) / (T 2 w 2 +4); calculate ,like Then record the period t as ;calculate ,like Then record the period t as ; calculate ,like Then record the period t as ;calculate ,like Then record the period t as ; Where kp and kr are set constants; Calculate the positive sequence impedance Z1p(F(i)) = A1p(F(i))∠ at port C1 with frequency F(i). 1p(F(i)); where A1p(F(i)) is the ratio of the magnitude of the positive-sequence voltage to the magnitude of the positive-sequence current, i.e. ;∠ 1p(F(i)) is the phase difference between the positive-sequence voltage U1p(F(i)) and the positive-sequence current I1p(F(i)), i.e. ; Calculate the positive sequence impedance Z2p(F(i)) = A2p(F(i))∠ at port D2 with frequency F(i). 2p(F(i)); where A2p(F(i)) is the ratio of the magnitude of the positive-sequence voltage to the magnitude of the positive-sequence current, i.e. ;∠ 2p(F(i)) is the phase difference between the positive-sequence voltage U2p(F(i)) and the positive-sequence current I2p(F(i)), i.e. ; Sequence impedance angle Zp(F(i))=Ap(F(i))∠ p(F(i)) is the sum of the magnitude and phase of the impedance measured at port C1 and port D1, respectively, i.e., Ap(F(i)) = A1p(F(i)) + A2p(F(i)); ∠ p(F(i))=∠ 1p(F(i))+∠ 2p(F(i)).

6. The method for measuring the impedance angle of a two-port three-phase disturbance according to claim 1, characterized in that, The PR phase-locked negative sequence impedance angle measurement method described in step 7 is as follows: the distributed power supply voltage and current sensing module C measures the voltage and current at port C1 in the t-th period every T sampling period, and separates the voltage and current components with frequency F(i), namely U1a(F(i),t), U1b(F(i),t), U1c(F(i),t) and I1a(F(i),t), I1b(F(i),t), I1c(F(i),t); The grid voltage and current sensing module D measures the voltage and current at port D1 in the t-th period every T sampling period, and separates the voltage and current components with frequency F(i), namely U2a(F(i),t), U2b(F(i),t), U2c(F(i),t) and I2a(F(i),t), I2b(F(i),t), I2c(F(i),t). Each time a sampling period T passes, t is incremented by 1 until... ; The three-phase voltage and current are separated into positive and negative sequences to obtain the negative sequence voltage. , and negative sequence current , ,in, ; Define sequence ,Will and Doing bad ,Right now ;set up , , ; Define sequence ,Will and Doing bad ,Right now ;set up , ; Define sequence ,Will and Doing bad ,Right now ;set up , ; Define sequence ,Will and Doing bad ,Right now ;set up , ; Calculate YU1p(F(i),t)=(-(2T 2 w 2 -8)×YU1p(F(i),(t - 1))-(T 2 w 2 +4)×YU1p(F(i),(t - 2))+(kp(T 2 w 2 +4)+2krT)×EU1p(F(i),t)+kp(2T 2 w 2 -8)×EU1p(F(i),(t - 1))+(kpT 2 w 2 +4kp - 2krT)×EU1p(F(i),(t - 2))) / (T 2 w 2 +4); Calculate YI1p(F(i),t)=(-(2T 2 w 2 -8)×YI1p(F(i),(t - 1))-(T 2 w 2 +4)×YI1p(F(i),(t - 2))+(kp(T 2 w 2 +4)+2krT)×EI1p(F(i),t)+kp(2T 2 w 2 -8)×EI1p(F(i),(t - 1))+(kpT 2 w 2 +4kp - 2krT)×EI1p(F(i),(t - 2))) / (T 2 w 2 +4); Calculate YU2p(F(i),t)=(-(2T 2 w 2 -8)×YU2p(F(i),(t-1))-(T 2 w 2 +4)×YU2p(F(i),(t-2))+(kp(T 2 w 2 +4)+2krT)×EU2p(F(i),t)+kp(2T 2 w 2 -8)×EU2p(F(i),(t-1))+(kpT 2 w 2 +4kp-2krT)×EU2p(F(i),(t-2))) / (T 2 w 2 +4); Calculate YI2p(F(i),t)=(-(2T 2 w 2 -8)×YI2p(F(i),(t - 1))-(T 2 w 2 +4)×YI2p(F(i),(t - 2))+(kp(T 2 w 2 +4)+2krT)×EI2p(F(i),t)+kp(2T 2 w 2 -8)×EI2p(F(i),(t - 1))+(kpT 2 w 2 +4kp - 2krT)×EI2p(F(i),(t - 2))) / (T 2 w 2 +4); calculate ,like Then record the period t as ;calculate ,like Then record the period t as ; calculate ,like Then record the period t as ;calculate If , then record the period t as ; Where kp and kr are set constants; Calculate the negative sequence impedance Z1p(F(i)) = A1p(F(i))∠ at port C1 with frequency F(i). 1p(F(i)); where A1p(F(i)) is the ratio of the magnitude of the negative-sequence voltage to the magnitude of the negative-sequence current, i.e. ;∠ 1p(F(i)) is the phase difference between the negative-sequence voltage U1p(F(i)) and the negative-sequence current I1p(F(i)), i.e. ; Calculate the negative sequence impedance Z2p(F(i)) = A2p(F(i))∠ at port D2 with frequency F(i). 2p(F(i)); where A2p(F(i)) is the ratio of the magnitude of the negative-sequence voltage to the magnitude of the negative-sequence current, i.e. ;∠ 2p(F(i)) is the phase difference between the negative-sequence voltage U2p(F(i)) and the negative-sequence current I2p(F(i)), i.e. ; Negative sequence impedance angle Zp(F(i)) = Ap(F(i))∠ p(F(i)) is the sum of the magnitude and phase of the impedance measured at port C1 and port D1, respectively, i.e., Ap(F(i)) = A1p(F(i)) + A2p(F(i)); ∠ p(F(i))=∠ 1p(F(i))+∠ 2p(F(i)).

7. The method for measuring the impedance angle of a two-port three-phase disturbance according to claim 1, characterized in that, The A1 port of the voltage disturbance injection module A is connected to the E3 port of the relay switching module E. The B1 port of the current disturbance injection module B is connected to the E4 port of the relay switching module E. The C1 port of the distributed power supply voltage and current sensing module C is an external port connected to the distributed power supply. The C2 port of the distributed power supply voltage and current sensing module C is connected to the E1 port of the relay switching module E. The D1 port of the grid voltage and current sensing module D is an external port connected to the grid. The D2 port of the grid voltage and current sensing module D is connected to the E2 port of the relay switching module E.

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