Active supporting capacity online monitoring method

Abstract

The invention discloses an active supporting capacity online monitoring method. The method comprises an overall framework of the online monitoring method. And capturing and analyzing the inertia response capability, the primary frequency modulation capability, the reactive voltage regulation capability and the fault ride-through capability. According to the invention, the active supporting capability of the new energy station is monitored on line, potential problems can be found and solved in time, and safe and stable operation of a power grid under the condition of high proportion of new energy is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of novel power systems, and in particular to an online monitoring method for active support capability. Background Art

[0002] Renewable energy generation lacks traditional synchronization characteristics and has poor active support capabilities, which has threatened the stability of the power grid.

[0003] By real-time monitoring of the active support capabilities of renewable energy grid connection points, potential problems can be discovered and resolved in a timely manner, ensuring the safe and stable operation of the power grid when renewable energy accounts for a high proportion. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of this, the purpose of the present invention is to develop an online monitoring method for active support capability to solve the problem in the prior art that the active support capability of new energy cannot be monitored online.

[0006] (II) Technical solution

[0007] The technical solution for online monitoring of active support capabilities generally consists of four steps:

[0008] The first step is to sample the three-phase voltage signal and the three-phase current signal of the grid-connected monitoring point;

[0009] The second step is to calculate the electrical parameters of each cycle based on the collected data to form a continuous single-cycle data stream.

[0010] The third step is to capture the frequency and voltage changes in the continuous single-cycle data stream to determine whether there is a need for active support response. If so, a preset time recording is performed and stored locally, and the background software is notified as an event in a timely manner; if not, no processing is performed and capture continues.

[0011] The fourth step is to analyze the captured recorded data, mainly to analyze whether the system has actively supported the response and the result of the response, and store the analysis results locally.

[0012] There are four specific aspects of online monitoring of active support capability: monitoring of inertia response capability, monitoring of primary frequency regulation capability, monitoring of reactive voltage regulation capability, and monitoring of fault ride-through capability.

[0013] The specific capture process is as follows:

[0014] 1) Capture frequency changes. If the frequency diverges continuously and the number of divergence points exceeds the threshold, and the frequency is within the dead zone during this period, it is determined that the system needs to perform an inertia response and record and save it for a preset period of time; otherwise, if the frequency exceeds the dead zone during this period, it is determined that the system needs to perform a frequency modulation response and record and save it for a preset period of time;

[0015] 2) Otherwise, continue capturing. If the frequency exceeds the dead zone range, it is determined that the system needs to perform a frequency modulation response and save the recording for a preset time.

[0016] 3) When receiving the reactive voltage regulation monitoring instruction, it starts capturing and recording the waveform according to the monitoring parameters. Otherwise, it does not monitor the reactive voltage regulation.

[0017] 4) Capture voltage changes in real time. If the voltage exceeds the threshold, it is determined that fault ride-through capability is required. At this time, a recording of a preset duration is performed and saved locally.

[0018] The specific analysis process is as follows:

[0019] 1) Analysis of inertia response

[0020] First, analyze whether the system has inertia response. Analyze the change in active power during the recording period to see whether it reaches the threshold. If not, it means that no inertia response has occurred. If so, analyze the inertia response.

[0021] The analysis of inertia response is mainly the calculation of inertia time constant, which is mainly based on the fact that the change of rotor kinetic energy is equal to the cumulative energy of the change of output electromagnetic power.

[0022] The change in rotor kinetic energy is:

[0023]

[0024] Cumulative energy of output electromagnetic power change:

[0025]

[0026] Relationship between moment of inertia J and inertia time constant Tj

[0027]

[0028] Jointly derive the calculation formula

[0029]

[0030] 2) Analysis of primary frequency modulation capability

[0031] First, analyze whether the system has performed a frequency modulation, and analyze the change in active power during the recording period to see whether it has reached the threshold. If not, it means that no frequency modulation has occurred; if so, analyze the inertial response.

[0032] Based on the standard curve, calculate the lag time, adjustment time and response time.

[0033] 3) Analysis of reactive voltage regulation capability

[0034] Determine whether the reactive power change during the recording period reaches the regulation threshold. If so, the reactive power voltage regulation meets the standard, otherwise it does not meet the standard.

[0035] 4) Analysis of fault ride-through capability

[0036] Analyze the voltage change during the recording period to analyze whether the system can continue to operate after crossing the dead zone and whether it has been operating for a period of time. If the set threshold is reached, the fault ride-through capability meets the standard, otherwise it does not meet the standard. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is the primary frequency modulation curve diagram of the present invention;

[0038] Figure 2 is the reactive power control capability diagram of the present invention;

[0039] Figure 3 is a low voltage ride-through capability requirement diagram of the present invention;

[0040] Figure 4 This is the high voltage ride-through capability requirement of the present invention.

Claims

1. An online monitoring method for active support capability, characterized in that: Sample the three-phase voltage signal and three-phase current signal of the grid-connected monitoring point; calculate the electrical parameters of each cycle based on the sampled data to form a continuous single-cycle data stream; and capture the frequency change and voltage change in the continuous single-cycle data stream to determine whether there is a need for active support response; if so, record the waveform for a preset time and store it locally, and notify the background software as an event in a timely manner; if not, do not do anything and continue capturing; The captured recorded data is analyzed to mainly analyze whether the system has actively supported the response and what the response result is.

2. With respect to the method of claim 1, the specific capturing method is as follows: 1) Capture frequency changes. If the frequency diverges continuously and the number of divergence points exceeds the threshold, and the frequency is within the dead zone during this period, it is determined that the system needs to perform an inertia response and record and save it for a preset period of time; otherwise, if the frequency exceeds the dead zone during this period, it is determined that the system needs to perform a frequency modulation response and record and save it for a preset period of time; 2) Otherwise, continue capturing. If the frequency exceeds the dead zone range, it is determined that the system needs to perform a frequency modulation response and save the recording for a preset time. 3) When receiving the reactive voltage regulation monitoring instruction, it starts capturing and recording the waveform according to the monitoring parameters. Otherwise, it does not monitor the reactive voltage regulation. 4) Capture voltage changes in real time. If the voltage exceeds the threshold, it is determined that fault ride-through capability is required. At this time, a recording of a preset duration is performed and saved locally.

3. According to the method described in claim 1, the specific analysis method is as follows: 1) Analysis of inertia response First, analyze whether the system has inertia response. Analyze the change in active power during the recording period to see whether it reaches the threshold. If not, it means that no inertia response has occurred. If so, analyze the inertia response. The analysis of inertia response is mainly the calculation of inertia time constant, which is mainly based on the fact that the change of rotor kinetic energy is equal to the cumulative energy of the change of output electromagnetic power. The change in rotor kinetic energy is: Cumulative energy of output electromagnetic power change: Relationship between moment of inertia J and inertia time constant Tj Jointly derive the calculation formula 2) Analysis of primary frequency modulation capability First, analyze whether the system has performed a frequency modulation, and analyze the change in active power during the recording period to see whether it has reached the threshold. If not, it means that no frequency modulation has occurred; if so, analyze the inertial response. Based on the standard curve, calculate the lag time, adjustment time and response time. 3) Analysis of reactive voltage regulation capability Determine whether the reactive power change during the recording period reaches the regulation threshold. If so, the reactive power voltage regulation meets the standard, otherwise it does not meet the standard. 4) Analysis of fault ride-through capability Analyze the voltage change during the recording period to analyze whether the system can continue to operate after crossing the dead zone and whether it has been operating for a period of time. If the set threshold is reached, the fault ride-through capability meets the standard, otherwise it does not meet the standard.

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