Station-level real fault voltage ride-through test method for new energy power station

Abstract

The invention relates to a station-level real fault voltage ride-through test method for a new energy power station, and belongs to the technical field of new energy access and control. The method comprises the following steps: firstly, controlling active power output of a whole-station new energy unit at a fixed value by using a new energy power station power control system; then, the SVG is controlled to carry out reactive step, and the influence condition of reactive output on the 35kV bus voltage is evaluated; secondly, a new energy power station power control system is used for controlling reactive power output of the new energy unit of the whole station, so that the actual voltage of the 35kV bus is close to the high and low voltage ride-through threshold values of the new energy unit; and finally, controlling the SVG to perform high-power step through the test equipment, triggering all the new energy units in the whole station to enter high and low voltage fault ride-through, and verifying the station-level high and low voltage ride-through response characteristics of the new energy power station. At the present stage, no test method for station-level fault ride-through of the new energy power station is developed in China, but the test method provided by the invention can truly simulate the actual response characteristics of the fault ride-through of the whole station of the new energy power station, and has universality.

Description

Technical Field

[0001] The present invention belongs to the technical field of new energy access and control, and in particular relates to a method for testing real fault voltage ride-through at a new energy power station site level. Background Art

[0002] In recent years, with the large-scale grid connection of new energy sources, the power system has shown a significant trend of power electronics. The low inertia and low short-circuit capacity of power electronic devices have made the power system face severe safety and stability issues. Therefore, the reactive power support capability of new energy power stations for the power grid has become increasingly important, especially when the power grid voltage fails and new energy power stations are required to provide necessary reactive power support.

[0003] At present, the high and low voltage ride-through tests of new energy power stations are all limited to single test objects, such as single wind turbines, photovoltaic arrays or SVGs, which cannot reflect the high and low voltage ride-through response characteristics of the entire new energy power station, nor can they reflect the reactive power support capacity of the entire new energy power station. Therefore, how to carry out high and low voltage ride-through tests of the entire new energy power station is an urgent problem to be solved in the field of new energy access and control technology. Summary of the invention

[0004] The purpose of the present invention is to address the deficiencies in the prior art and to provide a method for testing real fault voltage ride-through at a new energy power station level. The method realistically simulates the high and low voltage ride-through of a new energy power station so that the response characteristics presented by the test are consistent with the actual response characteristics. This method can truly reflect the reactive power support capacity of the entire new energy power station and can be used as a reference for power grid dispatching departments when performing mode calculations.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows: A method for testing a real fault voltage ride-through at a new energy power station site level, comprising the following steps: Step (1), using the power control system of the new energy power station to control the active output of all the new energy units in the new energy power station to a fixed value P 1 ; Step (2), control SVG to n Reactive power steps of different capacities, n The next step amount is recorded as (Δ Q 1 , Δ Q 2 , ..., Δ Q n ), n The 35kV bus voltage change corresponding to the step value is recorded as (Δ U 1 , Δ U2 , ..., Δ U n ),calculate n The secondary voltage influence coefficient is recorded as ( M 1... M n ), M 1 =Δ U 1 / Δ Q 1 , M 2 =Δ U 2 / Δ Q 2 ,……, M n =Δ U n / Δ Q n , to obtain n The mean value of the sub-voltage influence coefficient M ; M =( M 1 + M 2 + ... + M n ) / n ; Step (3), use the power control system of the new energy power station to control the reactive power output of the new energy units in the entire station, so that the 35kV bus voltage U Close to the low voltage ride-through threshold of new energy units U L Nearby, and U - U L ≤0.5kV; Step (4), set the initial reactive power of the new energy power station SVG to Q 0 =0.1 Q n ,in: Q n is the rated capacity of SVG, inductive reactive power is negative, and capacitive reactive power is positive; Step (5), according to the voltage influence coefficient M And fault voltage target value U m1 , U m1 < U L , calculate the reactive power target value of SVG Q1 , Δ U m1 = U m1 - U , Q 1 = Q 0 + M ×Δ U m1 ; Step (6), set the high voltage ride through control voltage of SVG to the grid connection point voltage of the new energy power station, and limit the rated capacity of SVG to Q 1 ; Step (7), connect the voltage disturbance device to the system-side voltage secondary measurement circuit of SVG, and output a settable duration through the voltage disturbance device t After receiving the high voltage ride-through signal, SVG generates inductive reactive power. Q 0 Step to Q 1 At this time, the 35kV bus voltage drops to U m1 Nearby, duration t After that, SVG reactive power from Q 1 Restore to Q 0 , that is, the low voltage ride-through test of the whole station is completed; Step (8), using the power control system of the new energy power station to control the reactive power output of the new energy units in the entire station, so that the 35kV bus voltage U Close to the high voltage ride-through threshold of new energy units U H nearby, U - U H ≤0.5kV, set the initial reactive power of the new energy power station SVG to Q 0 =-0.1 Q n ; Step (9), according to the voltage influence coefficient M And fault voltage target value U m2 , U H < U m2 , calculate the reactive power target value of SVG Q 2 , Δ U m2 =U m2 - U , Q 2 = Q 0 - M ×Δ U m2 ; Step (10), setting the low voltage ride-through control voltage of SVG to the grid connection point voltage of the new energy power station, and limiting the rated capacity of SVG to Q 2 ; Step (11), connect the voltage disturbance device to the system side voltage secondary measurement circuit of SVG, and output a settable duration through the voltage disturbance device t After receiving the low voltage ride-through signal, SVG sends out capacitive reactive power. Q 0 Step to Q 2 At this time, the 35kV bus voltage drops to U m2 Nearby, duration t After that, SVG reactive power from Q 2 Restore to Q 0 , that is, the high voltage ride-through test of the entire station is completed.

[0006] Furthermore, preferably, the new energy generator set is a wind turbine set or a photovoltaic inverter.

[0007] In step (1) of the present invention, the power control system of the new energy power station is an existing system. A power control system of the new energy power station is configured in each power station, and the present invention does not impose any special restrictions on it.

[0008] In step (2) of the present invention, since currently new energy power stations generally configure reactive power compensation devices in the power stations for reactive power compensation, and currently SVG is mainly configured, the present invention uses control of SVG to perform high and low penetration tests on the entire station.

[0009] In step (5) of the present invention, U m1 It is a custom voltage value that is less than the low voltage crossing threshold value of the new energy unit. It can be set by yourself In step (7) of the present invention, the voltage disturbance device outputs a settable duration t The SVG receives the high voltage through signal formed by the high voltage signal.

[0010] In step (9) of the present invention, Um2 It is a customized voltage value that is greater than the high voltage ride-through threshold of the new energy unit and can be set by yourself.

[0011] In step (11) of the present invention, the voltage disturbance device outputs a settable duration t The SVG receives the low voltage signal formed by this signal.

[0012] The present invention firstly uses the power control system of the new energy power station to control the active output of the new energy units of the whole station at a fixed value; then controls the SVG to perform reactive step, and evaluates the influence of reactive output on the 35kV bus voltage; secondly, uses the power control system of the new energy power station to control the reactive output of the new energy units of the whole station, so that the actual voltage of the 35kV bus is close to the high and low voltage crossing threshold value of the new energy units (wind turbines or photovoltaic inverters); finally, the SVG is controlled by the test equipment to perform a high power step, triggering all the new energy units of the whole station to enter the high and low voltage fault crossing, and verifying the high and low voltage crossing response characteristics of the new energy power station. At present, there is no test method for the field and station-level fault crossing of new energy power stations in China, and the test method involved in the present invention can truly simulate the actual response characteristics of the fault crossing of the whole station of the new energy power station, and has universal applicability.

[0013] Compared with the prior art, the present invention has the following beneficial effects: The present invention solves the problem that the current high and low voltage ride-through tests of new energy power stations are all limited to a single test object, and cannot reflect the high / low voltage ride-through response characteristics of the entire new energy power station, nor can it reflect the reactive power support capacity of the entire new energy power station. The method of the present invention truly simulates the high and low voltage ride-through of the new energy power station, so that the response characteristics presented by the test are consistent with the actual response characteristics, and can truly reflect the reactive power support capacity of the entire new energy power station, which can be used as a reference for the power grid dispatching department when performing mode calculations. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a flowchart of specific execution steps of the method for testing the real fault voltage ride-through at the station level of a new energy power station of the present invention; Figure 2 The present invention is a schematic diagram of the structure of a system for testing the real fault voltage ride-through of a new energy power station site. DETAILED DESCRIPTION

[0015] The present invention is further described in detail below in conjunction with embodiments.

[0016] Those skilled in the art will appreciate that the following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention. If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the art or the product specifications are used. If the manufacturer of the materials or equipment used is not specified, they are all conventional products that can be purchased. Example 1

[0017] like Figure 1 As shown, a method for testing real fault voltage ride-through at a new energy power station site level includes the following steps: Step (1), using the power control system of the new energy power station to control the active output of all the new energy units in the new energy power station to a fixed value P 1 ; Step (2), control SVG to n Reactive power steps of different capacities, n The next step amount is recorded as (Δ Q 1 , Δ Q 2 , ..., Δ Q n ), n The 35kV bus voltage change corresponding to the step value is recorded as (Δ U 1 , Δ U 2 , ..., Δ U n ),calculate n The secondary voltage influence coefficient is recorded as ( M 1... M n ), M 1 =Δ U 1 / Δ Q 1 , M 2 =Δ U 2 / Δ Q 2 ,……, M n =Δ U n / Δ Q n , to obtain n The mean value of the sub-voltage influence coefficient M ; M =( M 1 + M2 + ... + M n ) / n ; Step (3), use the power control system of the new energy power station to control the reactive power output of the new energy units in the entire station, so that the 35kV bus voltage U Close to the low voltage ride-through threshold of new energy units U L Nearby, and U - U L ≤0.5kV; Step (4), set the initial reactive power of the new energy power station SVG to Q 0 =0.1 Q n ,in: Q n is the rated capacity of SVG, inductive reactive power is negative, and capacitive reactive power is positive; Step (5), according to the voltage influence coefficient M And fault voltage target value U m1 , U m1 < U L , calculate the reactive power target value of SVG Q 1 , Δ U m1 = U m1 - U , Q 1 = Q 0 + M ×Δ U m1 ; Step (6), set the high voltage ride through control voltage of SVG to the grid connection point voltage of the new energy power station, and limit the rated capacity of SVG to Q 1 ; Step (7), connect the voltage disturbance device to the system-side voltage secondary measurement circuit of SVG, and output a settable duration through the voltage disturbance device t After receiving the high voltage ride-through signal, SVG generates inductive reactive power. Q 0 Step to Q 1 At this time, the 35kV bus voltage drops to U m1Nearby, duration t After that, SVG reactive power from Q 1 Restore to Q 0 , that is, the low voltage ride-through test of the whole station is completed; Step (8), using the power control system of the new energy power station to control the reactive power output of the new energy units in the entire station, so that the 35kV bus voltage U Close to the high voltage ride-through threshold of new energy units U H nearby, U - U H ≤0.5kV, set the initial reactive power of the new energy power station SVG to Q 0 =-0.1 Q n ; Step (9), according to the voltage influence coefficient M And fault voltage target value U m2 , U H < U m2 , calculate the reactive power target value of SVG Q 2 , Δ U m2 = U m2 - U , Q 2 = Q 0 - M ×Δ U m2 ; Step (10), setting the low voltage ride-through control voltage of SVG to the grid connection point voltage of the new energy power station, and limiting the rated capacity of SVG to Q 2 ; Step (11), connect the voltage disturbance device to the system side voltage secondary measurement circuit of SVG, and output a settable duration through the voltage disturbance device t After receiving the low voltage ride-through signal, SVG sends out capacitive reactive power. Q 0 Step to Q 2 At this time, the 35kV bus voltage drops to U m2 Nearby, duration t After that, SVG reactive power from Q2 Restore to Q 0 , that is, the high voltage ride-through test of the entire station is completed. Example 2

[0018] like Figure 1 As shown, a method for testing real fault voltage ride-through at a new energy power station site level includes the following steps: Step (1), using the power control system of the new energy power station to control the active output of all the new energy units in the new energy power station to a fixed value P 1 ; Step (2), control SVG to n Reactive power steps of different capacities, n The next step amount is recorded as (Δ Q 1 , Δ Q 2 , ..., Δ Q n ), n The 35kV bus voltage change corresponding to the step value is recorded as (Δ U 1 , Δ U 2 , ..., Δ U n ),calculate n The secondary voltage influence coefficient is recorded as ( M 1... M n ), M 1 =Δ U 1 / Δ Q 1 , M 2 =Δ U 2 / Δ Q 2 ,……, M n =Δ U n / Δ Q n , to obtain n The mean value of the sub-voltage influence coefficient M ; M =( M 1 + M 2 + ... + M n ) / n; Step (3), use the power control system of the new energy power station to control the reactive power output of the new energy units in the entire station, so that the 35kV bus voltage U Close to the low voltage ride-through threshold of new energy units U L Nearby, and U - U L ≤0.5kV; Step (4), set the initial reactive power of the new energy power station SVG to Q 0 =0.1 Q n ,in: Q n is the rated capacity of SVG, inductive reactive power is negative, and capacitive reactive power is positive; Step (5), according to the voltage influence coefficient M And fault voltage target value U m1 , U m1 < U L , calculate the reactive power target value of SVG Q 1 , Δ U m1 = U m1 - U , Q 1 = Q 0 + M ×Δ U m1 ; Step (6), set the high voltage ride through control voltage of SVG to the grid connection point voltage of the new energy power station, and limit the rated capacity of SVG to Q 1 ; Step (7), connect the voltage disturbance device to the system-side voltage secondary measurement circuit of SVG, and output a settable duration through the voltage disturbance device t After receiving the high voltage ride-through signal, SVG generates inductive reactive power. Q 0 Step to Q 1 At this time, the 35kV bus voltage drops to U m1 Nearby, duration t After that, SVG reactive power from Q 1 Restore to Q0 , that is, the low voltage ride-through test of the whole station is completed; Step (8), using the power control system of the new energy power station to control the reactive power output of the new energy units in the entire station, so that the 35kV bus voltage U Close to the high voltage ride-through threshold of new energy units U H nearby, U - U H ≤0.5kV, set the initial reactive power of the new energy power station SVG to Q 0 =-0.1 Q n ; Step (9), according to the voltage influence coefficient M And fault voltage target value U m2 , U H < U m2 , calculate the reactive power target value of SVG Q 2 , Δ U m2 = U m2 - U , Q 2 = Q 0 - M ×Δ U m2 ; Step (10), setting the low voltage ride-through control voltage of SVG to the grid connection point voltage of the new energy power station, and limiting the rated capacity of SVG to Q 2 ; Step (11), connect the voltage disturbance device to the system side voltage secondary measurement circuit of SVG, and output a settable duration through the voltage disturbance device t After receiving the low voltage ride-through signal, SVG sends out capacitive reactive power. Q 0 Step to Q 2 At this time, the 35kV bus voltage drops to U m2 Nearby, duration t After that, SVG reactive power from Q 2 Restore to Q 0 , that is, the high voltage ride-through test of the entire station is completed.

[0019] The new energy units are wind turbines or photovoltaic inverters. Example 3

[0020] like Figure 1 As shown, a method for testing real fault voltage ride-through at a new energy power station site level includes the following steps: Step (1), using the power control system of the new energy power station to control the active output of all the new energy units in the new energy power station to a fixed value P 1 ; (All new energy power stations will be equipped with a power control system, which is ready-made and used to control the active and reactive power output of the entire new energy power station) Step (2), since currently new energy power stations generally configure reactive power compensation devices in the power stations for reactive power compensation, and currently SVG is mainly configured, the present invention uses SVG to perform high and low penetration tests on the entire station. n Reactive power steps of different capacities, n The next step amount is recorded as (Δ Q 1 , Δ Q 2 , ..., Δ Q n ), n The 35kV bus voltage change corresponding to the step value is recorded as (Δ U 1 , Δ U 2 , ..., Δ U n ),calculate n The secondary voltage influence coefficient is recorded as ( M 1... M n ), M 1 =Δ U 1 / Δ Q 1 , M 2 =Δ U 2 / Δ Q 2 ,……, M n =Δ U n / Δ Q n , to obtain n The mean value of the sub-voltage influence coefficient M ; M =( M 1+ M 2 + ... + M n ) / n ; Step (3), use the power control system of the new energy power station to control the reactive power output of the new energy units in the entire station, so that the 35kV bus voltage U Close to the low voltage ride-through threshold of new energy units U L Nearby, and U - U L ≤0.5kV; Step (4), set the initial reactive power of the new energy power station SVG to Q 0 =0.1 Q n ,in: Q n is the rated capacity of SVG, inductive reactive power is negative, and capacitive reactive power is positive; Step (5), according to the voltage influence coefficient M And fault voltage target value U m1 ( U m1 It is a custom voltage value that is less than the low voltage ride-through threshold value of the new energy unit, which can be set by yourself). U m1 < U L , calculate the reactive power target value of SVG Q 1 , Δ U m1 = U m1 - U , Q 1 = Q 0 + M ×Δ U m1 ; Step (6), set the high voltage ride through control voltage of SVG to the grid connection point voltage of the new energy power station, and limit the rated capacity of SVG to Q 1 ; Step (7), connect the voltage disturbance device to the system-side voltage secondary measurement circuit of SVG, and output a settable duration through the voltage disturbance device tAfter receiving the high voltage ride-through signal (the voltage disturbance device outputs a high voltage signal, and the SVG receives the signal; the voltage disturbance device is an existing device), it emits inductive reactive power. Q 0 Step to Q 1 At this time, the 35kV bus voltage drops to U m1 Nearby, duration t After that, SVG reactive power from Q 1 Restore to Q 0 , that is, the low voltage ride-through test of the whole station is completed; Step (8), using the power control system of the new energy power station to control the reactive power output of the new energy units in the entire station, so that the 35kV bus voltage U Close to the high voltage ride-through threshold of new energy units U H nearby, U - U H ≤0.5kV, set the initial reactive power of the new energy power station SVG to Q 0 =-0.1 Q n ; Step (9), according to the voltage influence coefficient M And fault voltage target value U m2 ( U m2 It is a custom voltage value greater than the high voltage ride-through threshold of the new energy unit, which can be set by yourself). U H < U m2 , calculate the reactive power target value of SVG Q 2 , Δ U m2 = U m2 - U , Q 2 = Q 0 - M ×Δ U m2 ; Step (10), setting the low voltage ride-through control voltage of SVG to the grid connection point voltage of the new energy power station, and limiting the rated capacity of SVG to Q 2 ; Step (11), connect the voltage disturbance device to the system side voltage secondary measurement circuit of SVG, and output a settable duration through the voltage disturbance device t After receiving the low voltage ride-through signal (the voltage disturbance device outputs a low voltage signal, and the SVG receives the signal; the voltage disturbance device is an existing device), it issues capacitive reactive power. Q 0 Step to Q 2 At this time, the 35kV bus voltage drops to U m2 Nearby, duration t After that, SVG reactive power from Q 2 Restore to Q 0 , that is, the high voltage ride-through test of the entire station is completed.

[0021] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for testing real fault voltage ride-through at a new energy power station, characterized in that: The steps include: Step (1), using the power control system of the new energy power station to control the active output of all the new energy units in the new energy power station to a fixed value P 1; Step (2), control SVG to n Reactive power steps of different capacities, n The next step amount is recorded as (Δ Q 1, Δ Q 2, ..., Δ Q n ), n The 35kV bus voltage change corresponding to the step value is recorded as (Δ U 1, Δ U 2, ..., Δ U n ),calculate n The secondary voltage influence coefficient is recorded as ( M 1... M n ), M 1=Δ U 1 / Δ Q 1, M 2=Δ U 2 / Δ Q 2,……, M n =Δ U n / Δ Q n , to obtain n The mean value of the sub-voltage influence coefficient M ; M =( M 1+ M 2+ ... + M n ) / n ; Step (3), use the power control system of the new energy power station to control the reactive power output of the new energy units in the entire station, so that the 35kV bus voltage U Close to the low voltage ride-through threshold of new energy units U L Nearby, and U - U L ≤0.5kV; Step (4), set the initial reactive power of the new energy power station SVG to Q 0=0.1 Q n ,in: Q n is the rated capacity of SVG, inductive reactive power is negative, and capacitive reactive power is positive; Step (5), according to the voltage influence coefficient M And fault voltage target value U m1 , U m1 < U L , calculate the reactive power target value of SVG Q 1, Δ U m1 = U m1 - U , Q 1= Q 0+ M ×Δ U m1 ; Step (6), set the high voltage ride through control voltage of SVG to the grid connection point voltage of the new energy power station, and limit the rated capacity of SVG to Q 1; Step (7), connect the voltage disturbance device to the system-side voltage secondary measurement circuit of SVG, and output a settable duration through the voltage disturbance device t After receiving the high voltage ride-through signal, SVG generates inductive reactive power. Q 0 step to Q 1. At this time, the 35kV bus voltage drops to U m1 Nearby, duration t After that, SVG reactive power from Q 1Restore to Q 0, which means the low voltage ride-through test of the whole station is completed; Step (8), using the power control system of the new energy power station to control the reactive power output of the new energy units in the entire station, so that the 35kV bus voltage U Close to the high voltage ride-through threshold of new energy units U H nearby, U - U H ≤0.5kV, set the initial reactive power of the new energy power station SVG to Q 0=-0.1 Q n ; Step (9), according to the voltage influence coefficient M And fault voltage target value U m2 , U H < U m2 , calculate the reactive power target value of SVG Q 2, Δ U m2 = U m2 - U , Q 2= Q 0- M ×Δ U m2 ; Step (10), setting the low voltage ride-through control voltage of SVG to the grid connection point voltage of the new energy power station, and limiting the rated capacity of SVG to Q 2; Step (11), connect the voltage disturbance device to the system side voltage secondary measurement circuit of SVG, and output a settable duration through the voltage disturbance device t After receiving the low voltage ride-through signal, SVG sends out capacitive reactive power. Q 0 step to Q 2. At this time, the 35kV bus voltage drops to U m2 Nearby, duration t After that, SVG reactive power from Q 2Restore to Q 0, which means the high voltage ride-through test of the whole station is completed.

2. The method for testing the real fault voltage ride-through of a new energy power station according to claim 1, characterized in that: The new energy units are wind turbines or photovoltaic inverters.

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