10 results about "Current transformer saturation" patented technology

The present application provides a method for determining a distance to a fault in a power systems network. The method may involve determining, based on a set of measured voltage samples, a set of processed voltage samples; determining, based on a set of measured current samples, a set of processed reactive current samples, a set of processed resistive current samples, a set of processed negative sequence current samples, and a set of processed zero sequence current samples; selecting, based on an indication from a faulty phase indicator, a selected processed voltage sample, a selected processed reactive current sample, a selected processed resistive current sample, and a selected processed negative or zero sequence current sample; determining, based on the selected processed reactive current sample, that no distortion has occurred due to current transformer (CT) saturation; and calculating, based on the determination that no distortion has occurred, the distance to the fault.

The invention discloses a current transformer adaptive compensation and protection strategy dynamic adjustment method and system, which can accurately identify the saturation state of a current transformer, adaptively calculate a compensation current capable of suppressing the current saturation of the current transformer according to the real-time saturation state of the current transformer, and meanwhile, automatically adjust the protection strategy of the current transformer. A reliable current data source is provided for an external protection device according to the saturation state of the current transformer, and a corresponding protection strategy adjustment instruction sent to the external protection device is dynamically adjusted; therefore, it is ensured that the CT can still keep high measurement precision under the large fault current, the reliability, selectivity and adaptive capacity of an external protection device are comprehensively improved, and the development requirements for safe, flexible and efficient operation of a power grid in the future are met.

The present disclosure relates to a method for controlling a differential protection system for an electrical power system, the method comprising: sensing at least one first current through a first end of a transmission line of the electrical power system and at least one second current through a second end of the transmission line; determining, based on the sensed at least one first current and the sensed at least one second current, a first computed current and a second computed current; determining, based on the first computed current and the second computed current, at least one parameter; determining, based on the determined at least one parameter and / or the first computed current and the second computed current, a fault in the electrical power transmission line; and controlling, based on the fault, the differential protection system. The present disclosure also relates to a respective device and system.

This application provides a method for determining the distance to a fault in a power system network. The method may involve determining a set of processed voltage samples based on a set of measured voltage samples; determining a set of processed reactive current samples, a set of processed resistive current samples, a set of processed negative sequence current samples, and a set of processed zero sequence current samples based on a set of measured current samples; selecting selected processed voltage samples, selected processed reactive current samples, selected processed resistive current samples, and selected processed negative or zero sequence current samples based on an indication from a fault phase indicator; determining, based on the selected processed reactive current samples, that no distortion has occurred due to current transformer (CT) saturation; and calculating the distance to a fault based on the determination that no distortion has occurred.

Due to the fact that topological structures and control modes of a battery energy storage power station and a synchronous generator are obviously different, after the battery energy storage power station is connected, original fault current characteristics of a power transmission line of an electric power system are changed, traditional current differential protection has the risk of performance deterioration and even operation refusal, and safe and stable operation of the electric power system is seriously challenged. The invention discloses a battery energy storage power station AC tie line differential protection method based on a Ghost optimization multi-scale attention convolutional neural network, and the method comprises the steps: constructing a current track wrapping area image through collecting the current information of two sides of a line; and identifying a current track wrapping area image based on a multi-scale convolutional neural network improved by adopting a lightweight convolutional Ghost and a channel prior convolutional attention mechanism. The method is not influenced by access of a battery energy storage power station, internal and external faults can be accurately distinguished, and the method still has ideal effects under non-ideal conditions of current transformer saturation, current transformer measurement errors, noise and the like.

The invention discloses a current transformer saturation detection method and system based on machine learning. The method comprises the following steps: generating CT saturation waveforms under different working conditions based on an electromagnetic transient simulation program of a power system; performing category labeling to obtain a labeled CT saturation waveform sample set; processing each sample waveform in the CT saturation waveform sample set, respectively extracting time domain features, frequency domain features and transient features, and constructing a multi-domain feature set; carrying out supervised learning training on the multi-domain feature set by adopting an improved gradient boosting tree model, and constructing a CT saturation detection classifier; obtaining to-be-detected current waveform data, and executing feature extraction operation to obtain to-be-detected multi-domain feature vectors; and inputting the to-be-detected multi-domain feature vector into the trained CT saturation detection classifier, and outputting a classification result and prediction confidence of the CT saturation degree. According to the method, automatic grading of the CT saturation state is realized, and the problems of low saturation efficiency and poor accuracy of a traditional identification method are effectively solved.

The invention discloses a zero-sequence inrush current protection method based on a digital primary and secondary fusion pole-mounted circuit breaker, and relates to the technical field of power system power distribution network protection. According to the method, in each task polling cycle, whether a subsequent process is started or not is judged according to zero-sequence voltage and zero-sequence current; analyzing the secondary harmonic content of the zero-sequence current in a plurality of continuous periods to obtain the dynamic change characteristics of the zero-sequence current, and adjusting an internal counter according to the dynamic change characteristics; and finally, whether zero-sequence overcurrent protection is locked or not is judged according to the numerical value of the counter, and the zero-sequence overcurrent protection is opened when a reset condition is met. According to the method, the zero-sequence inrush current and the grounding fault current generated by no-load closing of the transformer can be reliably distinguished, the problem of zero-sequence overcurrent protection maloperation or operation refusal caused by saturation of the current transformer is effectively solved, and the power supply reliability of the power distribution network is improved.

A method for determining a distance to a fault in a power system network is provided. The method may involve: determining a set of processed voltage samples based on a set of measured voltage samples; determining a set of processed reactive current samples, a set of processed resistive current samples, a set of processed negative sequence current samples, and a set of processed zero sequence current samples based on the set of measured current samples; selecting a selected processed voltage sample, a selected processed reactive current sample, a selected processed resistive current sample, and a selected processed negative or zero sequence current sample based on an indication from the faulty phase indicator; determining, based on the selected processed reactive current sample, that no distortion occurs due to current transformer (CT) saturation; and calculating a distance to the fault based on a determination that no distortion occurs.

A method for identifying inrush current and short-circuit current in transformer differential protection, the method comprising: taking the phase difference of differential current when the transformer simultaneously occurs short-circuit fault during inrush current as the phase difference ladder criterion of differential current under different conditions, and identifying inrush current and short-circuit current in the transformer according to the phase difference ladder criterion. The scheme can construct the phase difference ladder criterion of differential current under different conditions according to the characteristics of inrush current and short-circuit current, and realize accurate identification and distinction of inrush current and short-circuit current, ensuring the correctness of the operation of transformer differential protection.

This invention discloses a current transformer saturation identification method utilizing the alternating characteristics of differential current across different zones. The method includes: acquiring current data; calculating the differential current to determine whether differential protection should be activated; calculating the accumulated differential charge to determine whether the accumulated differential charge meets the linear zone criterion; detecting whether the differential current meets the saturation zone criterion, and opening or closing the differential protection. This current transformer saturation identification method utilizing the alternating characteristics of differential current across different zones has several advantages: first, it uses integral quantization instead of traditional amplitude thresholds in differential charge analysis, which better reflects the saturation recovery characteristics of current transformers; second, sliding window integration can suppress high-frequency noise, and its integration process is equivalent to low-pass filtering; and third, it introduces an alternating characteristic verification mechanism of linear zone triggering and saturation zone tracking, which can solve the problem of false blocking. This ensures timely blocking of protection when saturation occurs outside the zone because the linear zone is followed by a saturation zone, and avoids false blocking when there is no saturation zone after a fault within the zone due to low current.