A method for monitoring electrical variables of a pole-mounted circuit breaker

Abstract

The present invention relates to the field of electric variable monitoring technology, and further to a method for monitoring electric variables of a pole-mounted circuit breaker. The method comprises: step 1: collecting multiple real-time electric variables of the pole-mounted circuit breaker, performing normalization processing on each real-time electric variable, and then nonlinearly fusing them into a single-dimensional electric variable observation sequence; step 2: obtaining historical sampling values ​​of multiple electric variable observation sequences within a fixed time delay interval to avoid the embedding dimension explosion caused by vector operations and to allow the low-dimensional manifold assumption to be explicitly reflected; step 3: combining and mapping the intrinsic state quantity with the insulation leakage current and the arc voltage difference, and predicting the phase voltage of the break in the future. The present invention can achieve high-precision, strong robustness and forward-looking localized fault warning and protection control, significantly improving the intelligent monitoring and safe operation capabilities of the pole-mounted circuit breaker in a complex power distribution environment.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric variable monitoring, and in particular relates to an electric variable monitoring method for a pole-mounted circuit breaker. Background Art

[0002] As an important protective switchgear at the end of the distribution network, pole-mounted circuit breakers are widely deployed in 10~35 kV medium-voltage distribution lines. Their operating status has a direct impact on the reliability of power supply and the efficiency of fault handling. Pole-mounted circuit breakers operate in harsh outdoor environments such as high temperature, rain, dust, and corrosion for a long time. They are prone to various nonlinear hidden faults such as contact degradation, insulation aging, coil demagnetization, dynamic closing mechanism jamming, and arc reignition. The traditional health status judgment method based on telemetry and telesignaling data relies on binary logic and manual experience, which is difficult to reflect the dynamic degradation process inside the circuit breaker. Therefore, there are potential hidden dangers such as "can trip but cannot close" and "seemingly normal but unable to disconnect the load". The existing research on pole-mounted circuit breaker status monitoring can be divided into the following categories: (1) life estimation method based on the number of operations or working years; (2) feature extraction method based on physical quantities such as contact resistance, current waveform, and voltage response; (3) pattern recognition method based on artificial intelligence; (4) remote data fusion method based on the Internet of Things platform. These technical routes each have their own advantages, but they still have limitations to varying degrees in terms of engineering applicability, universality, real-time performance and interpretability.

[0003] The first type of method uses the number of operations or service life of the equipment as core indicators to estimate the remaining life of a circuit breaker. This method is simple and low-cost, but it ignores the impact of factors such as operating environment, current level, and operational shock on the degradation rate of the equipment, making it difficult to reflect the actual operating status. For example, in high-load, high-frequency operating scenarios, a circuit breaker may experience problems such as a sudden increase in contact resistance or demagnetization of the closing mechanism even if it has not reached its rated lifespan. In contrast, in low-load, low-operation environments, the equipment may have been in good condition for a long time but still be replaced prematurely, resulting in a waste of resources. The second type of method installs sensors on the circuit breaker body to collect variables such as current, voltage, temperature rise, contact resistance, and closing time. These sensors extract typical features for rule matching or threshold judgment. This method has a certain degree of physical interpretability and is suitable for specific types of fault detection. However, it relies heavily on feature extraction and often requires manual adjustment of parameter settings, resulting in insufficient robustness. For example, contact resistance often fluctuates due to load current fluctuations, causing instantaneous jitter. If the threshold is too tight, it can easily lead to false positives, while if it is too loose, it can miss early contact degradation. Furthermore, various faults (such as coil demagnetization and mechanism jamming) may present similar current waveforms, making the features non-unique. The third category of methods, centered around algorithms such as artificial neural networks, support vector machines, and decision trees, utilizes existing samples for supervised learning to build fault identification models. These methods offer a certain degree of accuracy and adaptability when sufficient samples and high-quality data are available. However, AI models are highly dependent on the size of the sample library, the accuracy of data annotation, and the quality of model training. They also suffer from a common "black box" problem, making it difficult to explain the relationship between prediction results and the physical mechanisms of the equipment. In power system scenarios, engineers have high requirements for verifiability and physical consistency of the results, resulting in significant obstacles to the implementation of these methods in engineering projects. The fourth category emphasizes system integration across the sensing, transmission, and platform ends. Typical examples include collecting multi-dimensional sensor data through edge computing gateways and uploading it to cloud platforms for centralized analysis and display. These methods enhance the collaborative monitoring capabilities of multiple devices and enable remote centralized management. However, its status determination still relies heavily on platform rule libraries and template matching algorithms, failing to accurately model the device's actual operating status on the device itself, making it difficult to meet the control requirements of "local intelligent judgment + rapid closed-loop response." Furthermore, due to communication latency and bandwidth constraints, the upload cycle for key status data is difficult to reduce to milliseconds, making it impossible to achieve real-time response to transient processes such as sudden arcing and rapid demagnetization. Summary of the Invention

[0004] The main purpose of the present invention is to provide a method for monitoring the electrical variables of a pole-mounted circuit breaker. While improving the accuracy of state determination and reducing the false operation rate, the present invention significantly shortens the operation and maintenance response time, extends the service life of the equipment, reduces the risk of power outages, and provides interpretable and highly reliable online data support for lean asset management of the power grid.

[0005] In order to solve the above problems, the technical solution of the present invention is achieved as follows:

[0006] A method for monitoring electrical variables of a pole-mounted circuit breaker is provided, the method comprising:

[0007] Step 1: Collect multiple real-time electrical variables of the pole-mounted circuit breaker, perform normalization on each real-time electrical variable, and then nonlinearly fuse them into a single-dimensional electrical variable observation sequence;

[0008] Step 2: Within a fixed time delay interval, obtain multiple historical sampling values ​​of the electrical variable observation sequence and perform two nonlinear processing on each historical sampling value to obtain multiple scalar coordinates. Specifically, these include: using a harmonic function proportional to the sampling frequency for phase modulation to introduce time periodicity; using a gating function composed of the temperature of the excitation coil and the rated temperature rise to reduce the noise influence in the high-temperature section; and then compressing all scalar coordinates back to a single manifold intrinsic state quantity using a geometric mean method to avoid the embedding dimensionality explosion caused by vector operations and to explicitly reflect the low-dimensional manifold assumption.

[0009] Step 3: Combine and map the intrinsic state quantity with the difference between the insulation leakage current and the arc voltage to construct a real-time health index. Based on the comparison between the real-time health index and the health threshold, if the real-time health index exceeds the set health threshold, an early warning is issued. The real-time health index is continuously monitored, the instantaneous gradient of the real-time health index with respect to time is calculated, and the phase voltage of the fault in the future is predicted.

[0010] Furthermore, the real-time electrical variables include: the main circuit current of phase A of the pole-mounted circuit breaker, in A; the neutral line current, in A; the main circuit voltage of phase A of the pole-mounted circuit breaker, in V; the contact resistance, in Ω; the arc equivalent resistance, in Ω; the accumulated charge of the excitation coil, in C; the accumulated charge of the excitation coil at the previous historical time, in C; the sampling time delay step, in s, which is an integer multiple of the sampling period.

[0011] Furthermore, step 1 specifically includes: characterizing the total current intensity through the vector synthesis of the main circuit current of phase A of the pole-mounted circuit breaker and the neutral line current, reflecting the instantaneous power level in combination with the main circuit voltage of phase A of the pole-mounted circuit breaker, and using the total series resistance of the contact resistance and the arc equivalent resistance as the loss factor of the power transmission path to form a quantitative index of the instantaneous power transmission efficiency as a power efficiency index; at the same time, introducing a logarithmic sensitivity detection mechanism of the rate of change of the accumulated charge of the excitation coil, and performing a logarithmic transformation on the accumulated charge of the excitation coil and the absolute value of the accumulated charge increment of the excitation coil in the previous historical time to achieve amplified detection of tiny magnetic field disturbances and obtain a magnetic field sensitivity index; finally, the power efficiency index and the magnetic field sensitivity index are linearly superimposed to form a single-dimensional electrical variable observation sequence.

[0012] Furthermore, the scalar coordinates are obtained through the following process: a time periodicity detection mechanism based on the harmonic sequence of the sampling frequency is established, and the frequency domain separation of historical data is achieved through the embedding frequencies corresponding to different delayed embedding dimensions to ensure the independence of information at each historical moment in the frequency domain; in parallel, an adaptive noise suppression system based on the temperature of the excitation coil is constructed, and a dynamic gating function is established using the ratio of the excitation coil temperature to the rated temperature rise of the excitation coil. Under high temperature conditions, the signal weight is automatically reduced to suppress thermal noise interference, and the conversion of the historical electrical variable observation sequence information to the current scalar coordinates is realized through the ratio operation of the frequency domain modulation signal and the temperature gating function, where the intrinsic dimension of the manifold determines the number of historical time sample points required to construct the low-dimensional state.

[0013] Furthermore, the intrinsic state of the manifold is obtained through the following process: the scalar coordinates of all delayed embedding dimensions are processed using an equally weighted geometric averaging algorithm, each scalar coordinate is subjected to a unitary bias and then a fractional power operation is performed, and the power exponent is set to the inverse of the intrinsic dimension of the manifold to ensure the balanced contribution of information in each dimension, and finally a dimensionality reduction mapping of multidimensional discrete information to a single continuous manifold intrinsic state is achieved through a continuous multiplication operation. This state can achieve dimensional compression while maintaining the integrity of the original information.

[0014] Furthermore, the rated temperature rise of the excitation coil is obtained through the following process: based on the heat dissipation capability of the excitation coil to the environment through the thermal resistance path of the excitation coil under steady-state conditions, a linear thermal resistance relationship between power loss and temperature rise is established, and a safety factor is introduced to make a conservative correction to the theoretically calculated temperature rise. The numerical range of the safety factor ensures that the system has sufficient thermal safety margin under rated conditions, providing a benchmark reference value for the subsequent setting of the temperature gating function.

[0015] Furthermore, a quantitative evaluation of the real-time health index of the equipment health status adopts a multivariate coupling analysis method of the manifold intrinsic state quantity, insulation leakage current and arc voltage characteristics, specifically including: using the manifold intrinsic state quantity as the basic evaluation indicator of the equipment operating status, realizing the reverse correlation evaluation of the insulation performance by weighting the inverse square root of the insulation leakage current as the insulation weight, and introducing the normalized exponential function of the arc voltage time series change rate relative to the rated working voltage of the circuit breaker as the arc amplification factor to realize the exponential amplification of the arc characteristics on the real-time health index, and constructing a unified real-time health index that can comprehensively reflect the electrical health level of the equipment through the ternary product operation of the basic evaluation index, the insulation weight and the arc amplification factor.

[0016] Furthermore, the health threshold setting of the equipment health warning is based on the principle of determining the safety boundary under extreme working conditions, specifically including: establishing an insulation safety boundary according to the maximum allowable leakage current level that the equipment insulation system can withstand, and realizing the inverse constraint relationship of the maximum allowable leakage current on the health threshold through the inverse square root transformation to obtain the insulation constraint; at the same time, establishing an arc safety boundary based on the maximum allowable arc voltage transient amplitude that the arc system can withstand, and realizing the exponential constraint relationship of the arc transient on the health threshold through the normalized exponential transformation relative to the rated working voltage of the circuit breaker to obtain the arc constraint; finally, the comprehensive health threshold is determined by the product of the insulation constraint and the arc constraint.

[0017] Furthermore, the future evolution prediction of the phase voltage at the break is based on the superposition estimation method of the voltage benchmark of the phase A main circuit of the pole-mounted circuit breaker and the multi-physical field coupling correction: the phase A main circuit voltage of the pole-mounted circuit breaker is used as the initial benchmark value for the prediction, and the dynamic change trend of the equipment status is reflected by the time evolution gradient of the real-time health index. The time-varying correction factor is constructed by combining the prediction time step, vacuum magnetic permeability, copper conductivity, and the DC resistance of the excitation coil and the contact resistance characteristics. The ratio of the circuit breaker's thermal capacity to the equivalent capacitive energy storage is introduced as a correction index for the energy conversion characteristics. The correction amount of the voltage evolution is calculated through the synergistic effect of electromagnetic coupling, impedance evolution, and multi-physical fields of energy conversion. Finally, the quantitative prediction of the phase voltage at the break at future moments is achieved by superposition of the initial benchmark value and the correction amount.

[0018] The method for monitoring electrical variables of a pole-mounted circuit breaker in the example of the present invention has the following beneficial effects: by mapping the multi-source real-time electrical quantity of the pole-mounted circuit breaker into a single-dimensional observation sequence, and then using low-dimensional manifold reconstruction and geometric mean compression, a unified intrinsic state that can dynamically reflect the conduction power, insulation degradation, thermal degradation and arc disturbance is constructed, and then a health index is generated at the millisecond level and combined with the time gradient to complete the forward prediction of the break voltage, thus realizing a full-link local closed loop from sampling, evaluation to decision-making. This method completely abandons artificial experience coefficients, and all constants are derived from the circuit breaker nameplate or international physical constants. Therefore, it can be directly transplanted across models and manufacturers, and maintains numerical stability through standardization and logarithmic compression, avoiding false alarms and missed alarms caused by traditional threshold parameter adjustment. The core of the algorithm only involves multiplication, division, logarithm, cosine and exponential operations. It can run in real time on resource-constrained embedded controllers, does not rely on external cloud or complex neural networks, and has extremely high deployment feasibility. By automatically suppressing high-temperature noise through a temperature gating function, enhancing power frequency characteristics through cosine modulation, and exponentially amplifying early anomalies through a health index, this invention can issue early warnings at the incipient stages of faults such as insulation leakage, arc reignition, and contact erosion. It also triggers bypass voltage limiting or tripping in advance based on trend predictions, upgrading the protection strategy from passive over-limit to proactive proactive protection. Compared to traditional methods that rely solely on the number of operations or static characteristics, this invention significantly shortens operation and maintenance response time, extends equipment life, reduces the risk of power outages, and provides interpretable, highly reliable online data support for lean grid asset management while improving state determination accuracy and reducing false operation rates. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic flow chart of a method for monitoring electrical variables of a pole-mounted circuit breaker provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0021] refer to Figure 1 : A method for monitoring electrical variables of a pole-mounted circuit breaker, the method comprising:

[0022] Step 1: Collect multiple real-time electrical variables of the pole-mounted circuit breaker, perform normalization on each real-time electrical variable, and then nonlinearly fuse them into a single-dimensional electrical variable observation sequence;

[0023] First, the acquisition module is required to simultaneously read the line current, neutral current, phase voltage, contact resistance, arc equivalent resistance, and accumulated charge of the excitation coil under millisecond-level clock synchronization. This data is then uniformly and strictly timestamped to ensure that each subsequent fusion operation references the physical state at the logically identical instant. Next, the system non-dimensionalizes the six raw quantities based on the reference values ​​of rated current, rated voltage, rated on-resistance, and rated excitation charge given on the circuit breaker nameplate. This is done by dividing their respective instantaneous measurements by the corresponding rated values ​​and applying exponential smoothing filtering to suppress sampling noise. This step not only addresses the dominant bias caused by unit differences but also compensates for thermal drift caused by diurnal and seasonal temperature fluctuations in the equipment through sliding window tracking, ensuring that the normalized results maintain amplitude stability even in extreme climate scenarios. After normalization, the system enters the nonlinear fusion stage. The system regards the line current and phase voltage as energy input channels, converts them into instantaneous energy flow indicators through a power-based multiplication relationship, and then introduces contact resistance and arc resistance as dynamic blocking factors of energy flow. The real-time impact of conduction path degradation on energy flow is characterized by a fractional structure. At the same time, the neutral line current is often most sensitive to early insulation leakage when the three phases are unbalanced. Therefore, the absolute value is extracted separately and then amplified by square to enter the same fusion framework, so that it can still amplify the diagnostic weight of slight leakage under low load conditions.

[0024] To prevent the large pulses caused by arc interruption or reignition from causing spikes in the fusion sequence, the system also superimposes a logarithmic self-suppression channel between the power and resistance components. This maps the charge differences between adjacent sampling points in the excitation coil into magnetic potential perturbation energy, which is then injected into the fusion equation using logarithmic compression. This ensures that actual operational actions produce recognizable steps in the observation sequence while preventing numerical overflow caused by short-term impulses. All normalized and nonlinearly processed quantities are then written to the on-chip pipeline in a fixed order. The compound operation is completed by a hardware multiply-accumulator. The resulting single-dimensional observation sequence is a stream of equally spaced, pure scalar data containing high-order coupling relationships and filtered of significant noise. At the exit of the sequence generation, the firmware implements a sliding gate algorithm based on accumulated thermal energy to monitor the calculated temperature rise of the contacts and coil in real time. If overheating is detected beyond the design margin, the smoothing coefficient of the adjacent sampling steps is automatically adjusted to reduce the chronic increase in the sequence baseline caused by long-term thermal drift and ensure numerical centralization. The entire process, from bottom-level drivers to top-level value output, is encapsulated in the high-priority interrupt service of the real-time operating system, ensuring that all single-cycle operations are completed within the sampling interval without omission. The key intermediate data is written into the ring buffer through redundant check caching for subsequent manifold embedding algorithm calls.

[0025] Step 2: Within a fixed time delay interval, obtain multiple historical sampling values ​​of the electrical variable observation sequence and perform two nonlinear processing on each historical sampling value to obtain multiple scalar coordinates. Specifically, these include: using a harmonic function proportional to the sampling frequency for phase modulation to introduce time periodicity; using a gating function composed of the temperature of the excitation coil and the rated temperature rise to reduce the noise influence in the high-temperature section; and then compressing all scalar coordinates back to a single manifold intrinsic state quantity using a geometric mean method to avoid the embedding dimensionality explosion caused by vector operations and to explicitly reflect the low-dimensional manifold assumption.

[0026] Step 2 utilizes the delayed embedding concept from nonlinear dynamical systems theory to re-characterize the multidimensional internal degrees of freedom hidden behind the time series in an explicit and extremely low-dimensional manner, thereby providing physically interpretable state quantities for subsequent health assessment and trend prediction. Specifically, during the firmware initialization phase, the implementation process first sets a fixed delay step size and an embedding dimension sufficient to cover the control degrees of freedom based on the manufacturer's circuit breaker operating cycle, rated power frequency, and sampling rate, combined with the embedded storage capacity, to determine the depth of the historical snapshot buffer. After each new frame of observation sequence sampling is completed, the system pushes the current value into the circular buffer in chronological order and simultaneously pops out the oldest value to ensure that the buffer always stores several historical points with the same interval. Subsequently, the device enters the dual nonlinear transformation stage: first, a harmonic function modulation proportional to the sampling rate is applied to each historical value in the buffer, which is equivalent to attaching a phase label that changes synchronously with the power frequency to each historical point on the time axis. With the help of this phase information, the delayed embedded coordinates can maintain a sensitive response to periodic oscillations and harmonic disturbances, thereby being able to fully reveal the system's internal dynamic structure under working conditions such as power fluctuations, excitation circuit oscillations or low-frequency shaking.

[0027] Next, the system invokes a gating function based on the insulation grade temperature rise limit based on the excitation coil temperature reading at the same historical moment. This function is nearly transparent when the temperature is below the limit, but compresses the coordinate amplitudes when the temperature approaches or exceeds the limit. This suppresses bias in the state estimate caused by sensor noise or insulation dielectric electrical parameter drift in high-temperature environments, thereby ensuring that thermally induced drift does not misidentify healthy devices as abnormal. After completing harmonic modulation and temperature gating, the system obtains scalar coordinates equal to the embedding dimension. To avoid the computational burden of vector space parallel processing within the resource-constrained field controller, these coordinates are no longer retained in vector form. Instead, a geometric mean strategy is used to compress all coordinates into a single intrinsic state scalar. The geometric mean was chosen over the arithmetic mean or minimum-maximum reduction because it numerically balances the relative gains and losses of the coordinate amplitudes while naturally maintaining the linear separability of the multiplicative coupling relationship. This allows any subsequent health formula based on logarithmic or exponential mappings to be directly decomposed into the original coordinates for physical interpretation.

[0028] When calculating the geometric mean, to avoid overflow in floating-point multiplication when the embedding dimension is large, the system uses a piecewise logarithmic summation followed by exponential reduction. This algorithm significantly reduces the clock usage of the multiply-accumulator hardware while maintaining accuracy. After the intrinsic state scalar is generated, it is immediately written to a single-bit-deep output register. This register is exposed to the upper-level health assessment task via memory mapping, allowing the real-time health index to access the latest manifold data with extremely low latency. It is important to emphasize that to ensure that the delayed embedding fully captures dynamics at both high-frequency shocks and low-frequency trends, the firmware also maintains an adaptive tuning mechanism in the background. If the variance of the observation sequence is detected to increase sharply or the autocorrelation coefficient decreases significantly within a short period of time, the system automatically shortens the delay step size to capture high-frequency anomalies with more dense historical points. Conversely, if the observation sequence exhibits long-term slow drift, the delay step size is increased to improve the resolution of slowly varying degradations. This tuning process is implemented internally in the microcontroller using finite state machine logic, independent of external parameter input. This ensures that the manifold reconstruction is adaptively scaled to the actual system degrees of freedom across different operating seasons, load levels, and operating frequencies.

[0029] Step 3: Combine and map the intrinsic state quantity with the difference between the insulation leakage current and the arc voltage to construct a real-time health index. Based on the comparison between the real-time health index and the health threshold, if the real-time health index exceeds the set health threshold, an early warning is issued. The real-time health index is continuously monitored, the instantaneous gradient of the real-time health index with respect to time is calculated, and the phase voltage of the fault in the future is predicted.

[0030] The single manifold intrinsic state obtained in the previous step is integrated with key electrical variables that directly reflect insulation and interruption transients to generate a real-time health index that can instantly determine the equipment's safety margin. This allows for millisecond-level alarm triggering and future trend extrapolation. The implementation principle first considers the low-dimensional state after temperature gating as a concentrated expression of the device's global energy and structural coupling based on the operating mechanism of the pole-mounted circuit breaker. The leakage current amplitude, which is most sensitive to early insulation degradation, and the arc voltage difference, which is most intuitive for contact wear and arc restrike, are then selected to construct a ternary coupling relationship. At the firmware level, the system maintains a robust three-channel data path: the intrinsic state is written to a shared register by the manifold module during each sampling cycle; the leakage current is synchronously acquired via a high-resistance shunt connected to an isolated analog-to-digital converter; and the arc voltage difference is updated in real time by calculating adjacent differences in a high-speed sampling cache. The update timestamps of the three channels must be aligned to avoid false positives caused by cross-delays. In the health index calculation logic, the engineering implementation selected a mapping mode that combines multiplication and division and then logarithmically amplifies, so that when any of the three indicators deviates from the normal range, the index can present a monotonically rising response curve. When multiple indicators deteriorate at the same time, the index increase will present an exponential superposition effect, so that minor abnormalities and serious faults can be quickly distinguished in the numerical dimension.

[0031] To accommodate the natural drift of insulation current and arc voltage in environments with varying altitudes, humidity, and temperatures, the algorithm continuously collects two weeks of sliding average statistics as a dynamic baseline. The health threshold is set as the dynamic baseline multiplied by a fixed safety factor. This factor, derived from the manufacturer's factory inspection data for the same model of circuit breaker, typically remains constant. This ensures consistency across environments without introducing artifacts. If the calculated real-time health index exceeds the threshold, the firmware immediately generates a high-priority alarm within a local interrupt, signaling the upper-layer protection device and dispatch platform simultaneously via relay contacts, IEC-61850 messages, or wireless LoRa frames. Furthermore, because the index is a continuous output rather than a binary flag, the host computer can formulate tiered response strategies based on its specific value. For example, if the threshold exceeds 20%, a voice warning is issued; if it exceeds 50%, a bypass switch is activated; and if it exceeds 80%, a direct trip is initiated to shut down the circuit breaker. This enables tiered response to wear and loss of control.

[0032] In addition to a one-time threshold comparison, the algorithm also performs a time-difference calculation of the health index each cycle to obtain gradient information. This gradient is embedded in a small first-order extrapolator and used, along with nameplate constants such as the device's contact resistance, coil resistance, and equivalent thermal capacity, to estimate the likely value of the phase voltage at the break several sampling cycles into the future. This predicted value is displayed in a background visualization curve, allowing operations engineers to analyze the progress of contact degradation and serving as a trigger for premature action in the protection logic. To prevent false alarms caused by transient or harmonic grid interference, the system employs a dual-window judgment criterion: a short window with a length of five sampling points specifically captures sudden outages; a long window with a length of hundreds of sampling points primarily tracks slow-changing degradation. The alarm is only validated when both windows show an upward trend, thus avoiding false trips caused by short-term spikes. The entire process runs entirely within the edge controller of the circuit breaker itself, independent of the cloud, ensuring local condition assessment and protection tripping even in the event of communication interruptions. In addition, the algorithm implementation fully considers the needs of device aging and firmware upgrades. All thresholds and constants are encapsulated in independent read-only storage blocks. During upgrades, new parameters can be written in batches through an external handheld terminal without modifying the code, which greatly facilitates batch operation and maintenance.

[0033] Furthermore, the real-time electrical variables include: the main circuit current of phase A of the pole-mounted circuit breaker , unit is A; neutral current , unit is A; the main circuit voltage of phase A of the column circuit breaker , unit is V; contact resistance , in Ω; arc equivalent resistance , unit is Ω; the accumulated charge of the excitation coil , unit is C; the accumulated charge of the excitation coil in the previous historical time , unit is C; sampling time delay step , the unit is s, which is an integer multiple of the sampling period; For time.

[0034] In the method for monitoring the electrical variables of a pole-mounted circuit breaker proposed in the present invention, all the real-time collected data are based on a set of basic quantities with clear physical meanings, in which the phase A main circuit current of the pole-mounted circuit breaker is represented by the symbol The unit is ampere, which directly reflects the instantaneous current intensity when the load is transmitted through the contacts and busbar; the corresponding neutral line current is in amperes. It is also expressed in amperes and is used to capture the zero-sequence component changes caused by three-phase imbalance or insulation leakage. On the voltage side, the instantaneous phase voltage of the A-phase main circuit is recorded as , whose unit is volt, is a direct benchmark for constructing instantaneous power and judging the energy flow state of the system; in order to explicitly reflect the conduction quality in the energy flow link, the contact resistance is introduced and arc equivalent resistance The units of both are ohms. The former reflects the static closed conductive metal contact state, while the latter describes the dynamic blocking characteristics of the arc channel to the current during the breaking or restrike period. The accumulated charge of the excitation coil on the drive mechanism side is expressed in coulombs. and Description, they record the amount of magnetic potential energy stored in the coil at the current sampling moment and the previous historical delay moment. The difference between the two can quantify the impact of a tripping action on the system magnetic field distribution; delay step The unit is seconds and must be an integer multiple of the sampling period. This design ensures that the intervals between historical points in the buffer are uniform when subsequent delays are embedded, and the time variable Exists only as a unified index.

[0035] Through the clearly defined physical quantities mentioned above, the system can first normalize and map the current, voltage, resistance and charge of different dimensions to the same dimensionless scale in step 1, and then use the multiplication, division, logarithm and difference relationships between them to construct a single-dimensional observation sequence; in the delayed embedding process of step 2, each historical sampling point carries this set of quantized physical quantity characteristics, which are combined into scalar coordinates after harmonic modulation and temperature gating, and then compressed into intrinsic state quantities by geometric mean; and in step 3, the intrinsic state quantities are entered into the health index mapping model together with the leakage current and arc voltage difference, so that any or Any abnormal fluctuations will be immediately amplified and reflected in the index, while the change in coil charge provides the driving force for the time gradient of the index, thereby supporting the forward prediction of the future phase voltage of the fault. Furthermore, step 1 specifically includes: characterizing the total current intensity through the vector synthesis of the phase A main circuit current and the neutral line current of the pole-mounted circuit breaker, combining the phase A main circuit voltage of the pole-mounted circuit breaker to reflect the instantaneous power level, and using the total series resistance of the contact resistance and the arc equivalent resistance as the loss factor of the power transmission path to form a quantitative indicator of instantaneous power transmission efficiency; at the same time, a logarithmic sensitivity detection mechanism for the rate of change of the accumulated charge of the excitation coil is introduced. By performing a logarithmic transformation on the absolute value of the accumulated charge of the excitation coil and the accumulated charge increment of the excitation coil at the previous historical time, amplification detection of small magnetic field disturbances is achieved. Finally, the power efficiency index and the magnetic field sensitivity index are linearly superimposed to form a single-dimensional electrical variable observation sequence. Time series of electrical variable observations for:

[0036] .

[0037] In the whole structure, the molecular part It is an estimate of the instantaneous power flow intensity of the actual system. Neutral current Taking the square root of the sum of squares is equivalent to calculating the modulus of the instantaneous current vector in the A-phase main circuit and the neutral line, thus taking into account both the normal conduction current and the neutral line feedback caused by the three-phase imbalance. Multiplying them together gives an approximate expression for instantaneous power. Although this power does not take the power factor into account, in distribution-side analysis, the phase deviation is small, and this simplification can approximate the power transmission state at a low computational cost.

[0038] The energy flow product is placed in a The purpose of the fractional structure with denominator is to map the coupling ratio of instantaneous energy flow intensity to the equivalent impedance of the conduction path. It usually increases with contact surface wear, ablation or oxidation, so it is an important indicator to characterize long-term contact degradation; while the arc equivalent resistance The sum of these two resistances forms the instantaneous total impedance of the entire current path, accurately reflecting whether current can be effectively transferred to the load. When contact conditions are excellent and arcing is absent, the impedance is low, resulting in a high fractional value. However, when arcing occurs or contact deterioration is severe, the impedance increases, causing this term to drop significantly. The resulting fractional term collectively expresses the power transfer efficiency per unit impedance—that is, the electrical energy output per unit conduction resistance.

[0039] In addition to the power conduction path, the operating behavior of the circuit breaker is also clearly reflected in the formula, that is, by changing the charge of the excitation coil A logarithmic mapping introduces the second term, which forms the right half of the formula. The excitation coil is the driving source for the circuit breaker's closing or opening operations. Its internal magnetic potential is formed by charge accumulation. If there is a significant change in the coil charge between two sampling points, it indicates that the circuit breaker has just completed an operation event. This charge change is wrapped in a logarithmic function, which reduces its contribution when the change is small and significantly amplifies it when abrupt changes occur. The compression property of the logarithmic function also suppresses spikes in the overall sequence caused by charge jitter. The addition of a constant ensures that even zero charge difference does not result in an invalid logarithmic calculation. This design has two key implications: first, it provides a detectable path for circuit breaker operation, allowing operational events to be represented in the manifold; second, it prevents errors caused by drive disturbances from interfering with overall state judgment, ensuring robustness under high-frequency operating conditions.

[0040] entire The sequence structure achieves multiple goals: it unifies the units of different physical quantities within the same expression; establishes a nonlinear mapping relationship through the combination of fractions and logarithms; and introduces explicit nonlinear coupling through operations such as modulus, multiplication, and differentiation. More importantly, the expression contains no artificial adjustment factors or empirical parameters; all variables are derived from the real-time physical quantities collected by the device itself. This ensures that subsequent modeling will not reduce model adaptability due to individual differences, manufacturing deviations, or operating environment variations. At the engineering implementation level, the formula requires only basic addition, multiplication, square root, and logarithm operations, making it suitable for online real-time operation on low-resource embedded chips.

[0041] Furthermore, the scalar coordinates are obtained through the following process: establishing a time periodicity detection mechanism based on the harmonic sequence of the sampling frequency, realizing the frequency domain separation of historical data through the embedding frequencies corresponding to different delay embedding dimensions, and ensuring the independence of information at each historical moment in the frequency domain; in parallel, constructing an adaptive noise suppression system based on the temperature of the excitation coil, and using the ratio relationship between the temperature of the excitation coil and the rated temperature rise of the excitation coil to establish a dynamic gating function, automatically reducing the signal weight under high temperature conditions to suppress thermal noise interference, and realizing the conversion of the historical electrical variable observation sequence information to the current scalar coordinates through the ratio operation of the frequency domain modulation signal and the temperature gating function, where the intrinsic dimension of the manifold determines the number of historical time sample points required to construct the low-dimensional state. The scalar coordinates are:

[0042] ;

[0043] in, Indicates the The scalar coordinates corresponding to the delayed embedding dimensions; is the intrinsic dimension of the manifold, indicating how many sample points in historical time are used to construct the low-dimensional state; For the A sequence of observations of electrical variables with a delayed embedding dimension; Indicates the The excitation coil temperature of the delayed embedding dimension, in K; is the rated temperature rise of the excitation coil, in K; For the Embedding frequency of delayed embedding dimension, , is the sampling frequency.

[0044] By a given integer multiple of the sampling period The observation sequence Extract fragments on the historical axis to form arrive common Each sample represents the overall electrical state of the circuit breaker at a different instant in the past, thereby constructing a history vector sufficient to expand the system's degrees of freedom; however, in order to avoid the storage and computational overhead caused by vector operations, this formula does not directly retain the vector, but immediately applies cosine modulation to each historical segment. The embedded frequency of this modulation term is Proportional to the sampling frequency, making the difference The corresponding coordinates are distributed equidistantly in the frequency domain, so that the power frequency and its harmonic components are explicitly superimposed into the coordinate expression, ensuring that when the main circuit current or voltage has periodic oscillations caused by load fluctuations, the manifold coordinates can maintain a sensitive response with consistent phase. The denominator corresponding to the modulation term introduces the temperature gating function When the excitation coil temperature is much lower than the rated temperature rise, this function is approximately a constant of one, and has almost no effect on the coordinate amplitude. When the temperature approaches or exceeds the rated temperature rise, the exponential term increases significantly, causing the denominator to amplify rapidly, thereby suppressing the high-amplitude jitter caused by thermal noise.

[0045] In this way, the periodic modulation ensures the capture of harmonics and power frequency characteristics, and the temperature control gate suppresses the risk of noise amplification of the measured value in a high temperature environment. The two together ensure that each All contain the largest information entropy in the smallest scalar space. It is worth noting that Taken from Temperature sensor readings with the same historical index ensure consistent time base for thermal control and power observation; The insulation rating is directly given by the nameplate, and does not vary with the environment or operator experience, making this formula free of any adjustment factors. Overall, this structure achieves four levels of coupling: first, time coupling, which weaves different historical fragments into the coordinates using a uniform lag step; second, frequency coupling, which incorporates the power frequency and its harmonics into the state variables under cosine modulation; third, thermal coupling, which dynamically suppresses thermal degradation through a temperature gating function; and fourth, amplitude coupling, which leverages the nonlinear structure of the observation sequence itself to convey the relationship between current, voltage, and resistance.

[0046] When all Corresponding When the geometric mean is subsequently compressed into a single intrinsic state, these coupling relationships are not eliminated, but are retained in the combined weights of the exponent and the logarithm through the commutativity of multiplication and exponentiation. Therefore, the final low-dimensional flow morphology inherits the harmonic structure of the system and retains the suppression characteristics of thermal degradation. It also maintains stable and differentiable smoothness in numerical terms, providing a reliable prerequisite for the continuous evolution and gradient calculation of the real-time health index. During the implementation process, each calculation Only one read buffer, one multiplication, one cosine table lookup and one exponential table lookup plus division are required, which allows the generation of scalar coordinates to be completed within one clock cycle of the embedded microcontroller without the need for vector storage, greatly reducing the demand for on-chip memory and computing power; at the same time, the frequency index and intrinsic dimension The proportional relationship allows developers to dynamically adjust the dimension size according to the actual degree of freedom of the circuit breaker, and the embedding frequency varies with The linearly growing structure ensures that the increase in dimension will not cause frequency aliasing. Through this design, even in high altitude, strong sunlight or severe cold environment, the drastic change of the excitation coil temperature can be effectively limited by the gating function, and the harmonic injection caused by mechanical shock and electromagnetic interference common in industrial sites can be significantly revealed through cosine modulation, so that manifold analysis can not only accurately capture latent faults, but also distinguish whether it is electrical anomalies caused by structural thermal degradation or short-term harmonic interference. This method of completing multi-dimensional feature fusion at the scalar level eliminates the need for dimensionality reduction or feature selection in subsequent steps, and can directly perform health assessment and future trend prediction on a single intrinsic state, reflecting the comprehensive advantages of the present invention in algorithm compactness, physical interpretability and embedded deployability.

[0047] The intrinsic state of the manifold is obtained through the following process: the scalar coordinates of all delayed embedding dimensions are processed using the equally weighted geometric averaging algorithm, each scalar coordinate is subjected to a unitary bias and then a fractional power operation is performed. The power exponent is set to the inverse of the intrinsic dimension of the manifold to ensure the balanced contribution of information in each dimension, and finally a dimensionality reduction mapping of multidimensional discrete information to a single continuous manifold intrinsic state is achieved through a continuous multiplication operation. This state can achieve dimensional compression while maintaining the integrity of the original information.

[0048] Furthermore, the rated temperature rise of the excitation coil is obtained through the following process: based on the heat dissipation capability of the excitation coil to the environment through the thermal resistance path of the excitation coil under steady-state conditions, a linear thermal resistance relationship between power loss and temperature rise is established, and a safety factor is introduced to make a conservative correction to the theoretically calculated temperature rise. The numerical range of the safety factor ensures that the system has sufficient thermal safety margin under rated conditions, providing a benchmark reference value for the subsequent setting of the temperature gating function. Intrinsic state quantity of the manifold of time for:

[0049] The purpose of the plus-one operation is to ensure that any coordinate remains positive even when it reaches the theoretical lower limit (i.e., an extreme negative swing occurs instead of just zero), so as to avoid the overall result losing its physical meaning due to the appearance of negative values ​​or zero in the multiplication chain; The coordinates of the whole participate in the product, which means that if there is a significant abnormality in the state of a certain historical delay dimension, such as a sharp increase in instantaneous impedance due to arc reignition or compression of amplitude in the high temperature section due to thermal suppression mechanism, it will be directly reflected in the product as an overall increase or decrease, thus affecting Generate an amplified global response. Compared with the traditional arithmetic average, this global amplification can more accurately capture the degree of danger when the multi-dimensional state is synchronously unbalanced. At the same time, the product result is opened again. The geometric mean operation of the power also plays the role of normalizing the dimension and stabilizing the amplitude, so that no matter how the embedding dimension is adjusted, The magnitude of is stable within an interval of the same order as a single coordinate, which not only avoids the numerical explosion caused by dimensional expansion, but also ensures that no additional normalization is required when constructing the real-time health index using exponential mapping. Physically, this structure can be regarded as a manifold volume measure of the "balanced contribution of each historical state": when all It's almost zero time, is approximately equal to one, indicating that the system is in nominal working condition; when any one-dimensional coordinate shows positive or negative deviation, the geometric mean will deviate from one, indicating that the trajectory of the system on this time scale has deviated from the normal manifold. More importantly, due to The overall includes cosine harmonic modulation terms and temperature control suppression terms. The continuous changes on the time axis actually reflect the combined results of three forces: power frequency power perturbation, harmonic sideband energy, and thermal degradation rate. This makes It becomes a single indicator that is highly information-intensive and physically interpretable. During engineering implementation, in order to launch it on an embedded controller with extremely low latency , the firmware will usually The pre-calculated table is directly written into the lookup table, and then the algorithm of logarithmic summation and exponential reduction is used to convert the multiplication chain into a summation operation and eliminate the risk of floating-point multiplication overflow; combined with the loop expansion method, the whole The geometric mean index can be completed within one sampling period and will not cause a bottleneck in the refresh rate of real-time health indicators. It is worth emphasizing that when the system dynamically adjusts the embedding dimension to adapt to different loads or seasonal conditions, the geometric mean index Automatic renormalization of the scale eliminates the need to modify downstream thresholds, allowing the method to maintain the same false alarm and false negative rates under field conditions of different circuit breaker models, different sampling rates, and even different communication rates.

[0050] The rated temperature rise of the excitation coil is obtained through the following process: Based on the heat dissipation capacity of the excitation coil to the environment through the thermal resistance path of the excitation coil under steady-state conditions, a linear thermal resistance relationship between power loss and temperature rise is established, and a safety factor is introduced to make a conservative correction to the theoretically calculated temperature rise. The numerical range of the safety factor ensures that the system has sufficient thermal safety margin under rated conditions, providing a benchmark reference value for the subsequent setting of the temperature gating function. for:

[0051] ;

[0052] in is the power loss of the excitation coil, in W; is the thermal resistance of the excitation coil, in K / W; is the safety factor, ranging from 1.2 to 1.5.

[0053] In the overall thermal-electrical coupled modeling framework of the present invention, the rated temperature rise of the excitation coil is It is considered as the only constant used in the temperature gating function. It directly determines whether the gate denominator implements amplitude suppression on each historical coordinate in the delay embedding process of step 2, and therefore plays a decisive role in the morphology of the low-dimensional manifold and the sensitivity of the health index. The derivation of this formula follows the thermal balance principle of electrical products: under steady-state rated conditions, the copper loss inside the excitation coil is expressed as thermal power. The thermal resistance is transferred to the outer surface of the winding and then The heat source dissipates to the environment. When a stable temperature difference is formed between the heat source and the environment, the system enters thermal equilibrium. At this time, the increase in the winding temperature relative to the ambient temperature is the rated temperature rise. In order to ensure that the maximum temperature under long-term operation conditions is still lower than the limit allowed by the insulation level, a safety factor is introduced into the formula. , which is equivalent to setting a margin based on the product of thermal resistance and loss, so that the measured temperature rise under daily working conditions is far lower than the insulation aging threshold, where The value is determined based on the IEC motor insulation standard and the aging test results of the circuit breaker manufacturer, and is generally selected between 1.2 and 1.5. The DC resistance is given by the product of the rated excitation current and the coil DC resistance. The DC resistance can be obtained through four-wire measurement at 20°C and then converted to the actual operating temperature based on the temperature coefficient of copper. When the circuit breaker needs to work for a long time at high altitude or high ambient temperature areas, engineers will introduce the actual maximum ambient temperature and air density on site into the heat dissipation model for recalculation. , thus obtaining a more conservative temperature rise value that meets local climate conditions. It is determined by the thermal conductivity between the winding and the shell, ventilation conditions, insulation varnish thickness and installation position. It can be obtained through heat flow meter testing or finite element thermal field simulation in the prototype stage, while the statistical average value of type test is often used in the mass production stage. After these parameters are put into the formula, the , and write it into the constant table of the embedded firmware; Under normal circumstances, the excitation coil of Class B insulation is obtained at a room temperature of 40℃ The F grade is between 90K and 115K. Throughout the entire life cycle of the temperature gating function, it affects the degree of compression of the coordinate amplitude during high temperatures in summer and also determines the sensitivity of the gating function to amplification of slight anomalies during low temperatures in winter. Therefore, it is necessary to correctly evaluate and and for Leaving a reasonable margin is crucial to ensure that the model neither over-suppresses anomalies nor gives premature alarms. When the coil temperature rises due to changes in copper loss under extreme load conditions, the temperature control gate denominator increases and automatically decreases. The amplitude of the gating function is reduced to avoid the accumulation of high-temperature noise into false fault signals in the embedding dimension; and when the ambient temperature returns to normal, the gating function quickly returns to the linear region of approximation to unity, so that the manifold coordinates can maintain high resolution for the real electrical anomaly.

[0054] The quantitative assessment of the real-time health index of the equipment health status adopts a multivariate coupling analysis method of the manifold intrinsic state quantity, insulation leakage current and arc voltage characteristics. Specifically, the method includes: using the manifold intrinsic state quantity as the basic evaluation indicator of the equipment operating status, realizing the reverse correlation evaluation of the insulation performance by weighting the inverse square root of the insulation leakage current, and introducing a normalized exponential function of the arc voltage time series change rate relative to the rated working voltage of the circuit breaker to realize the exponential amplification of the arc characteristics on the real-time health index. Through the ternary product operation of the basic state, insulation weight and arc amplification factor, a unified real-time health index that can comprehensively reflect the electrical health level of the equipment is constructed. Real-time health index of time for:

[0055] ;

[0056] in, for Insulation leakage current over time, in mA; for Arc voltage at time, in V; for Arc voltage at time, in V; Rated working voltage of the circuit breaker, in V.

[0057] As the internal state quantity of the manifold obtained by delayed embedding geometric mean, it has already integrated multi-dimensional factors such as main circuit power transmission efficiency, contact impedance degradation amplitude, excitation coil thermal state and harmonic injection into a single scale; numerically Corresponding to the nominal operating trajectory, a value significantly higher or lower than 1 means that the system dynamics has deviated from the healthy manifold. The milliampere level is sampled into the denominator and first added to the constant 1 and then squared. Its design purpose is to soften the impact of small micro-leakage through the square root relationship, while ensuring that the denominator is not zero when there is no leakage current; when the insulation ages or is damp, causing the leakage current to increase significantly, the denominator increases, causing the overall exponent to decrease, thereby forming an immediate amplification of the insulation condition deterioration in terms of value. The third channel is the arc voltage differential. The exponential term of the drive, the numerator difference directly describes the instantaneous rise or fall of the arc channel voltage from the previous sampling period to the current sampling period, and this difference is then divided by the rated working voltage The cross-model normalization is then amplified by the exponential function to an exponential gain; the introduction of the exponential form can immediately reduce the arc voltage when a high-energy event such as contact erosion or short circuit breaking causes a sharp change. Even if there is a jump of orders of magnitude, it maintains an approximately linear response to slight jitter and does not cause false alarms.

[0058] The three physical channels are multiplicatively coupled and exhibit nonlinear mutual checks and balances: if the flow shape is slightly offset due to load fluctuations, If the insulation leakage current is slightly increased, but the arc voltage fluctuation is still low and the arc voltage fluctuates smoothly, the denominator and exponential term will suppress the slight deviation and ensure Stay in the safety belt; on the contrary, if contact degradation and insulation aging occur at the same time, that is, High and Increases, the denominator increases but cannot completely offset the multiplication amplification. The exponential term will be even worse when the arc disturbance is enhanced, thus driving Rapidly crossing the threshold triggers an alarm. This structure also has inherent time consistency because Differential period and manifold embedding delay The health index is completely consistent, so that the health index uses the same time window to jointly evaluate the dynamics and transient behavior in each sampling step; at the same time, because all variables are directly measured by physical quantities or calibrated by nameplate parameters, The calculation does not require any on-site parameter adjustment. In engineering, to ensure that extreme scenarios such as high temperature, strong harmonics or lightning strikes do not cause exponential explosion, the firmware uses the logarithmic domain accumulation method to perform exponential calculations, and then clips the results that are greater than the preset saturation value. This not only maintains the continuity of the values ​​within the boundary, but also prevents extreme values ​​from impacting the downstream protection logic. Combined with the above derivation of the threshold value of the present invention, it can be seen that on a typical 12 kV pole-mounted circuit breaker, when When it exceeds about 0.70, it enters the alarm zone. During real-time operation, the monitoring unit calculates the fixed sampling period in a cycle. If the index exceeds the threshold, a high priority interrupt is generated on the local MCU to trigger the hard relay to trip or remote signal upload; at the same time, the system also A five-point sliding gradient calculation is performed. If the gradient remains consistently positive and exceeds a 20% threshold, the fault is considered to be accelerating. At this point, the protection logic will trip with a shorter delay, thus suppressing the fault in its early stages. In this way, the health index not only provides a "good or bad" judgment based on static values ​​but also provides information on the fault's development rate through a continuous time evolution curve, laying the data foundation for predictive maintenance, lifespan assessment, and graded response.

[0059] The health threshold setting for equipment health warning is based on the principle of determining the safety boundary under extreme working conditions, including: establishing an insulation safety boundary based on the maximum allowable leakage current level that the equipment insulation system can withstand, and realizing the inverse constraint relationship between the maximum allowable leakage current and the health threshold through the inverse square root transformation; at the same time, establishing an arc safety boundary based on the maximum allowable arc voltage transient amplitude that the arc system can withstand, and realizing the exponential constraint relationship between the arc transient and the health threshold through the normalized exponential transformation relative to the rated working voltage of the circuit breaker, and finally determining the comprehensive health threshold through the product of the insulation constraint and the arc constraint. Health Threshold for:

[0060] ;

[0061] in, is the maximum allowable leakage current; is the maximum allowable arc voltage transient.

[0062] The threshold formula is completely determined by the maximum permissible leakage current available on the nameplate. and the maximum allowable arc voltage transient Its structure uses the same numerator-denominator and index coupling method as the real-time health index: It reflects the amount of leakage that the insulation system can tolerate under extreme working conditions. The square root operation ensures that a small leakage will not reduce the threshold unnecessarily. When the leakage current reaches the nameplate limit, the denominator value just lowers the threshold value, so that the measured leakage slightly above the limit can drive the index to break the warning level. The arc voltage rise limit specified by the manufacturer is normalized and compared with the rated voltage of the equipment, and amplified in an exponential form. When the actual arc differential approaches the limit, the exponential term increases to the upper limit required by the threshold. In this way, as long as any component of the real-time health index approaches the limit specification, will inevitably approach or exceed , thus triggering an early warning. The derivation logic follows the strictest thermal-electrical-insulation coordinated safety principle: if the insulation leakage has reached , even if the arc voltage is stable, the system is still judged to be critical; on the contrary, if the arc voltage transient reaches Even if the leakage current is still low, the threshold is still crossed, ensuring that the loss of control of a single link is sufficient to trigger an alarm. In terms of numerical values, taking a typical 12kV pole-mounted circuit breaker as an example, when and , input rated voltage to get This value is written to a read-only register during system initialization; no changes are required when replacing a circuit breaker of the same specification on-site. If upgrading to a higher rating, such as 24kV or 35kV, simply updating the nameplate parameters automatically calculates the new threshold, while the downstream protection logic and interface remain completely unchanged. On the other hand, because the denominator and exponent terms have opposing regulatory effects on different physical phenomena, in actual operation, the health index often requires simultaneous triggering of two channels to cross the threshold, providing a natural protection barrier against false alarms on-site. When one of the two channels deteriorates rapidly, the ultra-linear response of the exponential or denominator term ensures that the fault is amplified within milliseconds, preventing hidden dangers from being concealed. The simple form of the threshold formula also offers advantages in firmware implementation: the MCU only needs to perform a single logarithm and square root operation based on the three nameplate parameters stored in EEPROM at startup to cache the threshold in the register. Subsequent comparisons involve only floating-point subtraction, making it ideal for resource-constrained edge controllers operating unattended for extended periods of time.

[0063] The future evolution prediction of the phase voltage at the break is based on a superposition estimation method of the voltage reference of the phase A main circuit of the pole-mounted circuit breaker and the multi-physics coupling correction. The phase A main circuit voltage of the pole-mounted circuit breaker is used as the initial reference value for the prediction. The dynamic change trend of the equipment status is reflected by the time evolution gradient of the real-time health index. The time-varying correction factor is constructed by combining the prediction time step, vacuum magnetic permeability, copper conductivity, and the DC resistance of the excitation coil and the contact resistance characteristics. The ratio of the circuit breaker's thermal capacity to the equivalent capacitive energy storage is introduced as a correction index for the energy conversion characteristics. The correction value of the voltage evolution is calculated through the synergistic effect of electromagnetic coupling, impedance evolution, and multi-physics fields of energy conversion. Finally, the quantitative prediction of the phase voltage at the break at future moments is achieved by superimposing the reference voltage and the correction value. The prediction result is as follows:

[0064] ;

[0065] in, is the prediction time step, ; is the vacuum permeability; is the electrical conductivity of copper; for The DC resistance of the excitation coil at time, in Ω; is the thermal capacity of the circuit breaker, in J·K⁻¹; is the equivalent capacitive energy storage, in J·V⁻²; For the future time The possible values ​​of the phase voltage at the break.

[0066] The formula gives the future The phase voltage that the circuit breaker may withstand within the time window provides a decision basis for the automatic protection logic. Directly referencing the current A-phase line voltage as the reference potential means that the prediction is to evaluate the incremental additional risk at the existing bus voltage level; the second term is based on the proportional factor The introduction of time advance and material magnetic and electrical conductivity properties physically reflects the joint constraints of magnetic field energy accumulation rate and metal conductor heat dissipation capacity on future arc reignition voltage, among which vacuum permeability is the electromagnetic constant, and the electrical conductivity of copper represents the dissipation capacity of the conductor in the excitation circuit for transient current; the time gradient Capturing the rate at which the health index rises or falls over time, if the gradient is positive and large, it indicates that the system state is rapidly deteriorating in the direction of instability, and the predicted voltage gain will also increase accordingly; the proportional term before the gradient therefore maps the "deterioration rate" into the "future voltage rise", making the prediction result not only dependent on the current health level, but also pays more attention to its changing trend. The remaining power exponential factors Then the sum of the equivalent DC resistance of the driving winding and the contact is ratioed to the internal state of the manifold, and the heat capacity is used to calculate the Energy storage with equivalent capacitance The ratio of is used as an exponential index. This structure comes from the logarithmic linear derivation of the distribution rate of electromagnetic transient energy between the thermal and electric energy storage media: when the contact or coil resistance increases, the numerator becomes larger, resulting in an overall increase in the exponential term, which will further increase the predicted voltage, reflecting the amplification effect of conduction degradation on the open-distance potential; if the system heat capacity is large and the energy storage capacitance is small, the power exponent is larger, indicating that in equipment with weak thermal inertia and limited capacitance energy storage, once the resistance increases, it will be more likely to cause high voltage at the fracture, so protective measures must be taken earlier. On the contrary, when When it deviates from 1 and tends to decrease (mostly reflecting the continued existence of the arc channel or the decrease in conduction efficiency), the increase in the denominator will suppress the exponential term, indicating that the system has entered a low-power transmission state. At this time, even a slight increase in resistance will not significantly increase the fracture voltage. Therefore, the algorithm automatically reduces the predicted value to avoid false alarms. Through this composite exponential form, the prediction model couples the electromagnetic energy storage rate, heat dissipation capacity, contact resistance degradation rate and overall dynamic health trend, providing a future-oriented prediction without the need for any external empirical factors. At the implementation level, the embedded firmware first uses the differential method to calculate the , and then call the exponentiation table to complete the exponential operation, the floating point overhead is limited to the single cycle allowed range; if If the safety limit set by IEC62271-100 or user-defined is exceeded, the system will immediately enter the early protection state. Combined with communication and execution delays, this allows ample time for bypass switching, voltage limiter activation, or rapid tripping. Overall, the prediction formula maps the system's current "state snapshot" and "rate of change" to quantifiable future voltage threats, upgrading traditional passive protection based on static threshold tripping to proactive, trend-based prevention.

[0067] The present invention was implemented on a 12kV, 630A pole-mounted circuit breaker. The sampling frequency was 1kHz, and the delay step was sampling points, the intrinsic dimension of the manifold .

[0068] Current moment :

[0069] ,

[0070] ,

[0071] ,

[0072] ,

[0073] ,

[0074] , .

[0075] ;

[0076] One step before :Use the same method to get . Two steps ago :have to .

[0077] Excitation coil temperature 345K, rated temperature rise , Modulation Selection .then:

[0078] ;

[0079] .

[0080] Insulation leakage current (0.0012 per unit), arc voltage .

[0081] then .

[0082] The nameplate allows a maximum leakage of 2mA and a maximum arc transient of 40V.

[0083] .

[0084] current It is only 0.057 higher, which is in the "Level 1 Warning" zone. The system will issue an alarm instead of tripping immediately.

[0085] ;

[0086] ;

[0087] Gradient Approximation

[0088] ;

[0089] (here Using the same method, we obtain 0.744.)

[0090] Contact resistance Substitute

[0091] .

[0092] The voltage rise was only 2V, far below the upper limit of 1.5 times the rated value. The automation device maintained operation based on this but continued high-frequency monitoring.

[0093] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features thereof can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for monitoring electrical variables of a pole-mounted circuit breaker, characterized in that: The method comprises: Step 1: Collect multiple real-time electrical variables of the pole-mounted circuit breaker, perform normalization on each real-time electrical variable, and then nonlinearly fuse them into a single-dimensional electrical variable observation sequence; Step 2: Within a fixed time delay interval, obtain multiple historical sampling values ​​of the electrical variable observation sequence and perform two nonlinear processing on each historical sampling value to obtain multiple scalar coordinates. Specifically, these include: using a harmonic function proportional to the sampling frequency for phase modulation to introduce time periodicity; using a gating function composed of the temperature of the excitation coil and the rated temperature rise to reduce the noise influence in the high-temperature section; and then compressing all scalar coordinates back to a single manifold intrinsic state quantity using a geometric mean method to avoid the embedding dimensionality explosion caused by vector operations and to explicitly reflect the low-dimensional manifold assumption. Step 3: Combine and map the intrinsic state quantity with the difference between the insulation leakage current and the arc voltage to construct a real-time health index. Compare the real-time health index with the health threshold. If the real-time health index exceeds the set health threshold, an early warning is issued. The real-time health index is continuously monitored, its instantaneous gradient with respect to time is calculated, and the future phase voltage at the fault is predicted. Real-time health index of time for: ； in, for Insulation leakage current over time; for Arc voltage over time; for Arc voltage over time; is the rated working voltage of the circuit breaker; is the sampling time delay step, for The intrinsic state quantity of the manifold of time.

2. The method for monitoring the electrical variables of a pole-mounted circuit breaker according to claim 1, wherein: Real-time electrical variables include: phase A main circuit current of the pole-mounted circuit breaker, unit: A; neutral line current, unit: A; phase A main circuit voltage of the pole-mounted circuit breaker, unit: V; contact resistance, unit: Ω; arc equivalent resistance, unit: Ω; accumulated charge of the excitation coil, unit: C; accumulated charge of the excitation coil at the previous historical time, unit: C; sampling time delay step, unit: s, which is an integer multiple of the sampling period.

3. The method for monitoring the electrical variables of a pole-mounted circuit breaker according to claim 2, wherein: Step 1 specifically includes: characterizing the total current intensity through the vector synthesis of the main circuit current of phase A of the pole-mounted circuit breaker and the neutral line current, reflecting the instantaneous power level in combination with the main circuit voltage of phase A of the pole-mounted circuit breaker, and using the total series resistance of the contact resistance and the arc equivalent resistance as the loss factor of the power transmission path to form a quantitative index of the instantaneous power transmission efficiency as a power efficiency index; at the same time, introducing a logarithmic sensitivity detection mechanism of the rate of change of the accumulated charge of the excitation coil, and performing a logarithmic transformation on the absolute value of the accumulated charge of the excitation coil and the accumulated charge increment of the excitation coil in the previous historical time to realize the amplified detection of small magnetic field disturbances and obtain the magnetic field sensitivity index; finally, the power efficiency index and the magnetic field sensitivity index are linearly superimposed to form a single-dimensional electrical variable observation sequence.

4. The method for monitoring the electrical variables of a pole-mounted circuit breaker according to claim 3, wherein: The scalar coordinates are obtained through the following process: establishing a time periodicity detection mechanism based on the harmonic sequence of the sampling frequency, realizing the frequency domain separation of historical data through the embedding frequencies corresponding to different delayed embedding dimensions, and ensuring the independence of information at each historical moment in the frequency domain; in parallel, constructing an adaptive noise suppression system based on the temperature of the excitation coil, and establishing a dynamic gating function using the ratio of the excitation coil temperature to the rated temperature rise of the excitation coil, automatically reducing the signal weight under high temperature conditions to suppress thermal noise interference, and realizing the conversion of the historical electrical variable observation sequence information to the current scalar coordinates through the ratio operation of the frequency domain modulated signal and the temperature gating function, where the intrinsic dimension of the manifold determines the number of historical time sample points required to construct the low-dimensional state.

5. The method for monitoring the electrical variables of a pole-mounted circuit breaker according to claim 4, wherein: The intrinsic state of the manifold is obtained through the following process: the scalar coordinates of all delayed embedding dimensions are processed using the equally weighted geometric averaging algorithm, each scalar coordinate is subjected to a unitary bias and then a fractional power operation is performed. The power exponent is set to the inverse of the intrinsic dimension of the manifold to ensure the balanced contribution of information in each dimension, and finally a dimensionality reduction mapping of multidimensional discrete information to a single continuous manifold intrinsic state is achieved through a continuous multiplication operation. This state can achieve dimensional compression while maintaining the integrity of the original information.

6. The method for monitoring the electrical variables of a pole-mounted circuit breaker according to claim 5, wherein: The rated temperature rise of the excitation coil is obtained through the following process: based on the heat dissipation capability of the excitation coil to the environment through the thermal resistance path of the excitation coil under steady-state conditions, a linear thermal resistance relationship between power loss and temperature rise is established, and a safety factor is introduced to make a conservative correction to the theoretically calculated temperature rise. The numerical range of the safety factor ensures that the system has sufficient thermal safety margin under rated conditions, providing a benchmark reference value for the subsequent setting of the temperature gating function.

7. The method for monitoring the electrical variables of a pole-mounted circuit breaker according to claim 6, wherein: The quantitative assessment of the real-time health index of the equipment health status adopts a multivariate coupling analysis method of manifold intrinsic state quantity, insulation leakage current and arc voltage characteristics. Specifically, the method includes: using the manifold intrinsic state quantity as the basic evaluation indicator of the equipment operating status, weighting the insulation performance by the inverse square root of the insulation leakage current as the insulation weight, and introducing the normalized exponential function of the arc voltage time series change rate relative to the rated working voltage of the circuit breaker as the arc amplification factor to achieve the exponential amplification of the arc characteristics on the real-time health index. Through the ternary product operation of the basic evaluation indicator, the insulation weight and the arc amplification factor, a unified real-time health index that can comprehensively reflect the electrical health level of the equipment is constructed.

8. The method for monitoring the electrical variables of a pole-mounted circuit breaker according to claim 7, wherein: The health threshold setting for equipment health warning is based on the principle of determining the safety boundary under extreme working conditions, specifically including: establishing an insulation safety boundary based on the maximum allowable leakage current level that the equipment insulation system can withstand, and realizing the inverse constraint relationship of the maximum allowable leakage current on the health threshold through the inverse square root transformation to obtain the insulation constraint; at the same time, establishing an arc safety boundary based on the maximum allowable arc voltage transient amplitude that the arc system can withstand, and realizing the exponential constraint relationship of the arc transient on the health threshold through the normalized exponential transformation relative to the rated working voltage of the circuit breaker to obtain the arc constraint; finally, the comprehensive health threshold is determined by the product of the insulation constraint and the arc constraint.

9. The method for monitoring the electrical variables of a pole-mounted circuit breaker according to claim 8, wherein: The future evolution prediction of the phase voltage at the break is based on a superposition estimation method of the voltage benchmark of the phase A main circuit of the pole-mounted circuit breaker and the multi-physical field coupling correction. The phase A main circuit voltage of the pole-mounted circuit breaker is used as the initial benchmark value for the prediction. The dynamic change trend of the equipment status is reflected by the time evolution gradient of the real-time health index. The time-varying correction factor is constructed by combining the prediction time step, vacuum magnetic permeability, copper conductivity, and the DC resistance of the excitation coil and the contact resistance characteristics. The ratio of the circuit breaker's thermal capacity to the equivalent capacitive energy storage is introduced as a correction index for the energy conversion characteristics. The correction amount of voltage evolution is calculated through the synergistic effect of electromagnetic coupling, impedance evolution, and multi-physical fields of energy conversion. Finally, the quantitative prediction of the phase voltage at the break at future moments is achieved by superimposing the initial benchmark value and the correction amount.

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