Plasma jet human body contact electrical safety assessment method and device

Abstract

The invention provides a plasma jet human body contact electrical safety assessment method, which comprises the following steps: step S01, collection of optical characteristics of plasma jet, including collection of discharge voltage and current signals; and S02, collecting current flowing through the human body impedance model. S03, calculating the effective value of the current flowing through the human body and the specific pulse energy, and S04, when the effective value of the current and the specific pulse energy do not exceed the safety threshold value, judging that the human body contact is safe, otherwise, judging that the human body contact is unsafe. The invention also provides a plasma jet human body contact electrical safety evaluation test platform. According to the method, the current effective value is used for evaluating the harm caused by the average effect of the human body contact jet plume and the human body contact dangerous situation caused by the instantaneous effect of the specific pulse energy evaluation, and the current effective value and the specific pulse energy are synthesized to form a human body contact safety evaluation system.

Description

Technical Field

[0001] The present invention belongs to the field of plasma jet human contact electricity, and relates to a method and device for evaluating the electrical safety of plasma jet human contact. Background Art

[0002] At normal temperature and atmospheric pressure, plasma is often generated by high-voltage electric fields breaking down working gases, which are rich in various highly reactive ions, free radicals, and high-energy electrons. Research has found that the interaction of the above active substances with organisms can induce relevant biomedical responses and has been applied in many fields such as sterilization, hemostasis, wound healing, and tumor treatment. Low-temperature plasma jets can be widely used in the biomedical field because the plasma generation region and the treatment region can be effectively separated, enabling flexible adaptation to different treatment surfaces, and have important potential application values. However, during the process of contact treatment with biological tissues, its electrical safety in human contact is an important aspect that needs to be considered.

[0003] During the interaction between the plasma plume formed by the breakdown of the working gas by the high-voltage electric field in the plasma jet and the human body, there is a situation where charged particles flow through the human body to form a loop current, which may put the object to be treated in an electrical safety hazard. Therefore, it is very necessary to evaluate the electrical safety when the plasma jet directly treats the human body. In addition, relevant plasma jet medical devices must also meet the requirements of electrical safety standards before they can enter clinical applications. Evaluating the electrical safety of human contact with plasma jets and related devices is not only to protect the safety of patients and operators, but also to ensure the safety and unity of relevant devices entering clinical applications.

[0004] However, the existing technology generally evaluates by calculating the effective value of the current. Researchers often only focus on the Joule heat generated by the average effect of the current and the safety threshold of the effective value of the current. This method is a commonly used means to evaluate the electrical safety of human contact with plasma jets. Through this method, it is possible to judge to a certain extent whether the human body is safe when contacting the plasma jet. However, calculating the effective value of the current can mainly evaluate the contact hazard caused by the average effect and is no longer applicable to the instantaneous effect caused by discharge pulses with short durations.

[0005] With the increasing entry of pulse-driven discharge plasmas into the field of medical applications, in addition to the average effect, the instantaneous effect generated when the plasma jet contacts the human body is also an important aspect that needs to be considered.

[0006] Patent CN202110923505.5 discloses an adaptive touchable plasma device and its control method. By collecting the human contact current and comparing it with a preset human safe contact current threshold, the output voltage is adjusted to keep the human contact current of the plasma generating device within the safety threshold range. This patent only compares the collected human contact current of the plasma generating device with the built-in safety current threshold. The proposed safety current threshold does not consider the average effect and instantaneous effect, and the safety current threshold is not safe. Summary of the Invention

[0007] 1. Technical problems to be solved:

[0008] Currently, there are few evaluation systems for the electrical safety of human contact with plasma jets. Research methods such as direct human contact with the jet plume have subjective feelings and risks; observing the discharge state of the jet plume to identify the safety of human contact is not advisable without quantitative calculation as a judgment basis; and the results obtained only using the effective current value are relatively one-sided and do not consider the instantaneous effect of human contact. The resulting data cannot be used as a standard for evaluating safety.

[0009] 2. Technical solutions:

[0010] To solve the above problems, the present invention provides an evaluation method for the electrical safety of human contact with plasma jets, including the following steps:

[0011] Step S01: Collection of the electrical characteristics of the plasma jet, and the collection of the electrical characteristics includes the collection of discharge voltage and current signal.

[0012] Step S02: Collection of the current flowing through the human impedance model.

[0013] Step S03: Calculate the effective value of the current flowing through the human body by Equation (1), and calculate the specific impulse energy by Equation (2):

[0014]

[0015] where I Prms is the effective current value, i p is the instantaneous current value, and T is the calculation period. P e is the specific impulse energy, that is, the electrical energy absorbed by the unit resistance; t i is the duration of the single discharge current.

[0016] Step S04: When neither the effective current value I prms nor the specific impulse energy P e exceeds the safety threshold, it is determined that the human contact is safe; otherwise, it is determined that the human contact is unsafe.

[0017] The effective current value IPrms Calculate P within 1 s e Calculate the strongest discharge current pulse.

[0018] The human impedance model is placed at different positions from the outlet of the plasma jet to be evaluated, for testing the presence or absence of the human impedance model and the influence of different positions on I H And the influence on the jet plume.

[0019] Record I of the human load model at different distances H respectively calculate the effective value and specific pulse energy according to the calculation formulas of I Prms and P e When both I Prms and P e are less than the safety threshold, the device to be evaluated realizes safe human contact at this distance.

[0020] According to the distance for realizing safe human contact, a protective sleeve is provided at the front end of the jet plume of the plasma jet generator to ensure that the human contact with the plasma plume is within the safe range.

[0021] According to the discharge equivalent circuit model and the human equivalent circuit model, calculate and determine the plasma plume resistance, and determine the range of the plume resistance value at the safe distance.

[0022] In order to achieve safe contact with the plasma jet, in addition to changing the distance, it is also possible to connect a protective resistor with a resistance value not less than the equivalent plume resistance calculated above in series on the high-voltage side to limit I Prms and P e to achieve safe human contact.

[0023] The present invention also provides a test platform for evaluating the electrical safety of human contact with a plasma jet, including a driving power supply, a digital oscilloscope and a human impedance model. A high-voltage probe and a first current coil are respectively connected to the digital oscilloscope. The plasma jet device to be evaluated is placed in the position area. The high-voltage probe is connected to the high-voltage electrode of the plasma jet device to be evaluated to measure the voltage of the high-voltage electrode; the first current coil is connected to the human impedance model to measure the current I flowing through the plume and the human impedance model H； The human impedance model is in contact with the plasma jet plume through a metal sheet, and also includes a second current coil and a third current coil connected to the digital oscilloscope. The second current coil is connected to the grounding electrode to measure the current I of the grounding electrode lead G ; the third current coil is arranged between the power supply and the high-voltage electrode to measure the total current I passing through the high-voltage electrode W, the human body impedance model is the human body equivalent load model proposed in the report of the international standard IEC - for electrical equipment safety assessment. The plasma jet device includes a plasma jet generator and a main body device. The main body device includes a power supply and a gas cylinder. The working gas in the gas cylinder enters the plasma jet generator after passing through a pressure reducing valve, a valve, and a gas flow meter.

[0024] The plasma jet generator adopts a needle - ring DBD structure and includes a stainless - steel tube. The stainless - steel tube is arranged inside a hollow quartz tube. There is a copper ring below the quartz branch tube. The gap between the upper part of the quartz tube and the stainless - steel tube is filled with a sealant.

[0025] The outer wall of the quartz tube is wrapped with nylon material as an insulating shell.

[0026] 3. Beneficial effects:

[0027] The present invention takes into account both the instantaneous effect in a single cycle of high - voltage discharge and the average effect in multiple cycles. Based on this device platform, through the measurement and analysis of the electrical and optical characteristics of plasma jet discharge, the evaluation quantity 1, the effective current value I Prms is proposed to evaluate the harm brought by the average effect of human contact with the jet fluid plume, and the evaluation quantity 2, the specific pulse energy P e is used to evaluate the dangerous situation of human contact caused by the instantaneous effect. The comprehensive evaluation quantities 1 and 2 form a human - contact safety evaluation system. The present invention considers from two perspectives of the average effect and the instantaneous effect, solves the electrical safety problem when the human body contacts the plasma jet, and takes into account both the instantaneous effect during contact and the average effect during long - term contact. Description of the drawings

[0028] Figure 1 is the flow schematic diagram of the present invention.

[0029] Figure 2 is the electrical safety evaluation test platform for plasma jet human contact.

[0030] Figure 3 is the schematic diagram of the main body device.

[0031] Figure 4 is the schematic diagram of the plasma jet generator.

[0032] Figure 5 is the electrical safety evaluation quantity for plasma human contact, where Figure 5 (a) is the electrical safety evaluation quantity for human contact under MCP, Figure 5 (b) is the electrical safety evaluation quantity for human contact under HCP.

[0033] Figure 6are the voltage and current waveforms at 7.1 kV, 2.2 kHz, and 0.8 slm, where Figure 6 (a) Without a human body load model; Figure 6 (b) With a human body load model at D = 3.45 cm; Figure 6 (c) With a human body load model at D = 3.35 cm, streamer discharge image; Figure 6 (d) With a human body load model at D = 3.35 cm, spark discharge image; Figure 6 (e) With a human body load model at D = 3.05 cm.

[0034] Figure 7 are I Prms and P e under different applied voltages and working distances at f = 2.2 kHz, V = 0.7 L / min, where Figure 7 (a) is the waveform diagram of I Prms ; Figure 7 (b) is the waveform diagram of P e .

[0035] Figure 8 are I Prms and P e under different applied voltages and working distances at f = 2.1815 kHz, U = 7.1 kV, where Figure 8 (a) is the waveform diagram of I Prms ; Figure 8 (b) is the waveform diagram of P e .

[0036] Figure 9 are I Prms and P e under different power frequencies and working distances at V = 0.8 L / min, U = 7.1 kV, where Figure 8 (a) is the waveform diagram of I Prms ; Figure 8 (b) is the waveform diagram of P e .

[0037] Figure 10 is a schematic diagram of the area of electrical safety for human contact in jet discharge.

[0038] Explanation of reference numerals: 101. Power supply; 2. Plasma jet generator; 201. Sealant filling; 202. Stainless steel tube; 203. Copper ring; 204. Protective sleeve; 205. Insulating housing; 206. Quartz tube; 207. Jet fluid plume; 3. High-voltage probe; 301. Gas cylinder; 302. Pressure reducing valve; 304. Valve; 305. Gas flowmeter; 4. First current coil; 5. Digital oscilloscope; 6. Human body impedance model; 601. Metal sheet; 8. Second current coil; 9. Third current coil. Detailed implementation mode

[0039] The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0040] As Figure 1 shown, the present invention provides a method for evaluating the electrical safety of plasma jet human contact, including the following steps:

[0041] Step S01: Acquisition of the electrical characteristics of the plasma jet, and the electrical characteristic acquisition includes the acquisition of discharge voltage and current signal.

[0042] Step S02: Acquisition of the current flowing through the human impedance model.

[0043] Step S03: Calculate the effective value of the current flowing through the human body by formula (1), and calculate the specific pulse energy by formula (2):

[0044]

[0045] Where I Prms is the effective value of the current, i p is the instantaneous value of the current, and T is the calculation period. P e is the specific pulse energy, that is, the electric energy absorbed by the unit resistance; t i is the duration of the single discharge current.

[0046] Step S04: When neither the effective value of the current I prms nor the specific pulse energy P e exceeds the safety threshold, it is determined that the human contact is safe, otherwise it is determined that the human contact is unsafe.

[0047] Evaluate the safety of the device when in human contact from the electrical perspective. Since it is considered that as long as there is a strong pulse during actual contact, there will be adverse reactions when in human contact, so the effective value I H of the branch current I Prms (mA) passing through the human impedance model and the specific pulse energy P e (A 2 ·s) are calculated respectively by combining formula (1) and (2).

[0048] Human contact electrical safety evaluation quantity 1 (effective value I H of the branch current I Prms passing through the human impedance model): As shown in 5(a), even if the plume currents of the jet fluid all show micro-current pulses with relatively small peaks and durations in the ns level, but under the cumulative effect of time, from the evaluation quantity 1 (formula 1), when calculating the effective value I H of the branch current I Prms passing through the human impedance branch, the human contact may still be in a dangerous state.

[0049] Human body contact electrical safety evaluation quantity 2 (specific pulse energy P e ): Figure 5 As shown in (b), during a complete discharge cycle, I H exhibits a large number of microcurrent pulses and a very small number of large current pulses with larger peaks and a duration of μs level. Because as long as there is a large current pulse during the process of human body contacting the jet fluid plume, there will be adverse reactions when the human body makes contact. By calculating the specific pulse energy P e , it is possible to determine whether human body contact is dangerous.

[0050] The current coil measures the current I of the jet grounding electrode lead under the cycle G , and the current coil 4 measures the current I of the plasma plume under the cycle P (I H ), the high-voltage probe 3 measures the voltage waveform. In one embodiment, the influence of adding a human body equivalent load model before and after and placing the human body equivalent load model at different positions on the jet electrical characteristics of the device is explored at a high-voltage pulse amplitude of 7.1 kV, a frequency of 2.2 kHz, and 0.8 slm. As shown in 6 Figure 6 (a) is the current-voltage waveform diagram without a human body load model Figure 6 (b) is the current-voltage waveform diagram with a human body load model at D = 3.45 cm Figure 6 (c) shows the streamer discharge state Figure 6 (d) shows the spark discharge state

[0051] Figures 7 - 9 The influences of changing parameters such as the applied voltage magnitude, gas flow rate, applied voltage frequency, and the contact distance between the human body load model and the plume on I Prms , P e are discussed

[0052] 1) The area where the dots are located in the figure is the streamer discharge, the area where the squares are located is the streamer-spark critical discharge, and the area where the triangles are located is the spark discharge state

[0053] 2) In the figure, different regions are correspondingly divided according to the measured effective values of the pulse current from small to large of the data points, and they correspond to the schematic diagram of the regions shown in Figure 10

[0054] 3) In 7, both I Prms and P e show an increasing trend with the increase of the applied voltage or the decrease of the working distance

[0055] 4) Most of the I Prms1 in 7(a) is below 0.6 mA, but when the voltage increases to 10.6 kV, I Prms1 even reaches about 0.65 mA​

[0056] 5) I Prms2 is basically above 1 mA. However, when the voltage is low, I Prms2 also shows values below 1 mA, even around 0.64 mA (6.1 kV); I Prms3 all exceed 1 mA.

[0057] 6) 7(b) calculates P under the same experimental conditions as 7(a) e . P e1 are all less than 10 -9 A 2 ·s;

[0058] 7) P e2 is in the range of 10 -7 ~10 -5 A 2 ·s, and the lowest value appears when the applied voltage is low;

[0059] 8) P e3 changes little and is similar to P e2 . The above results are because in the streamer discharge state, the working distance is relatively far and large current pulses cannot be generated. However, when the applied voltage is high, a large number of microcurrent pulses exist, and the accumulated I Prms1 is large, but the peak value of the microcurrent pulse is small and the duration is at the ns level. Therefore, the value of P e1 is small;

[0060] 9) In the streamer-spark critical discharge state with a low applied voltage, the peak value of the generated large current pulse is not large enough and there are also few microcurrent pulses. Therefore, I Prms2 , P e2 will show smaller values;

[0061] 10) In the spark discharge state, the number of large current pulses is large and the current peak increases with the increase of the voltage. I Prms3 is generally large, but the change in the working distance has little effect on P e3 when the applied voltage is low.

[0062] 11) The critical distance corresponding to the streamer-spark critical discharge state first increases rapidly and then tends to level off with the increase of the applied voltage.

[0063] Figure 8 The changes of I Prms and P e with the changes of Q and D are discussed separately. The corresponding detailed explanations are as follows:

[0064] 1) I Prms and P e both show an increasing trend with the decrease of the working distance.

[0065] 2) Similar to 7(a), most of the I in 8(a) Prms1 is below 0.6 mA. When the flow rate exceeds 1 L / min, I Prms1 starts to increase and even reaches about 0.71 mA. This is because the jet is in the laminar-turbulent transition period at this time, and the body plume gradually becomes unstable, the discharge tends to be uneven, and the contact area between the body plume and the human impedance model increases, and the number of discharge channels increases, resulting in an increase in the number of microcurrent pulses, so the value of I Prms1 is relatively large;

[0066] 3) I Prms2 is basically above 1 mA. Some smaller values appear at lower flow rates (below 1 L / min), and the minimum value is about 0.65 mA. This may be because the body plume converges at the end due to the small flow rate at this time. Although the human equivalent load model has a drainage effect, the contact area between the body plume and the human load model is small, the discharge channel is narrow, and the applied voltage is small, resulting in a small peak value of HCP and a small number of microcurrent pulses;

[0067] 4) I Prms3 is similar to 7(a) and both exceed 1 mA. Under the same experimental conditions, P in 8(b) e1 is all less than 10 -9 A 2 ·s, and both P e2 and P e3 are in the range of 10-7 to 10-5 A 2 ·s.

[0068] 5) The critical distance corresponding to the streamer-spark critical discharge state shows a trend of being small at both ends and large in the middle with the increase of the flow rate, and its maximum value appears at 1 L / min.

[0069] Figure 9 The influences of f and D on I Prms and P e are also discussed. It can be seen that within the power supply frequency range of 0.5 - 3 kHz, the influence on P e and the critical distance is not significant. The value ranges of I Prms and P e are basically the same as those described above. The maximum value of I Prms1 is about 0.604 mA, and the minimum value of I Prms2 is about 0.586 mA.

[0070] According to the above results, formula (3) gives the ranges of the effective current value I Prms and the specific pulse energy P e corresponding to different discharge states within the given parameter range in this paper.

[0071] 1) The RMS value (I Prms ) and the specific energy of a single pulse (P e ) are both important factors that must be considered when evaluating the safety of the device in the case of human contact.

[0072] 2) In the streamer-spark critical discharge state, the RMS value may be low. Considering only the safety standard of the RMS value of the discharge current, human contact is safe at this time.

[0073] 3) Once a spark channel is formed, it poses a potential danger to the human body.

[0074] 4) Even in the fully streamer discharge state (P e is small) without spark generation, if the RMS value exceeds a certain specific value, human contact is considered unsafe.

[0075]

[0076] Furthermore, according to the different working distances corresponding to formula (3), combined with the safety of human contact with the jet fluid plume, the present invention preliminarily proposes a Figure 10 schematic diagram of the region of electrical safety of jet discharge human contact as shown. The corresponding detailed explanations are as follows:

[0077] 1) In the figure, the critical distance corresponding to the streamer-spark critical discharge is used as the division. Above the critical region corresponds to the spark discharge state, and below the critical region is the streamer discharge state.

[0078] 2) Within the dangerous working distance, if a human body contacts the fluid plume, there will be a strong electric shock tingling sensation, and there is a risk of ventricular fibrillation and even possible life endangerment.

[0079] 3) Within the risk working distance, on the one hand, the average effect of the continuous pulse current poses a potential hazard to the human body. On the other hand, the parameter values of the human body equivalent circuit model will change due to factors such as individual differences, skin surface conditions, and discharge contact area, resulting in risks such as pain or startle reactions when the human body contacts the jet fluid plume at this distance.

[0080] 4) Within the safe distance, since I Prms , P e are both less than the safety threshold, it is relatively safe for the human body to contact the jet fluid plume.

[0081] The present invention creatively starts from the instantaneous effect in a single cycle and the average effect in multiple cycles of human contact with the jet fluid plume, and proposes two evaluation quantities for the electrical safety of human contact with the jet fluid plume. Only when both evaluation quantities are satisfied can the human body safely contact.

[0082] The present invention also provides a test platform for evaluating the electrical safety of plasma jet human contact, as Figure 2 shown, which includes a power supply 101, a digital oscilloscope 5 and a human impedance model 6. A high-voltage probe 3 and three current coils are respectively connected to the digital oscilloscope 5, and the plasma jet device is placed in the position area 10.

[0083] The high-voltage probe 3 is arranged between the power supply 101 and the digital oscilloscope 5 to measure the voltage obtained by the high-voltage electrode.

[0084] The first current coil 4 is connected to the human impedance model 6 to measure the current I flowing through the human impedance model by the body plume. H；。

[0085] The second current coil 8 is connected to the grounding electrode to measure the grounding electrode lead current I. G .

[0086] The third current coil 9 is arranged between the power supply 101 and the high-voltage electrode to measure the total current I passing through the high-voltage electrode. W .

[0087] The human impedance model 6 is in contact with the plasma jet plume 207 through a metal sheet 601.

[0088] The human impedance model 6 is the human equivalent load model mentioned in the report of the international standard IEC 60601-1 for electrical equipment safety assessment.

[0089] The periodic jet grounding electrode lead current I is measured by the second current coil 8. G , the periodic plasma plume current I is measured by the first current coil 4. P I H , the voltage waveform is measured by the high-voltage probe 3. It is possible to explore the influence of adding the human equivalent load model 6 before and after and placing the human equivalent load model at different positions on the jet electrical characteristics of the device under different high-voltage pulse amplitudes, frequencies, and gas flows, as well as the influence of changing the applied voltage U, gas flow Q, power supply frequency f, working distance D between the ground electrode and the human impedance model, and contact distance between the human load model and the plume on I Prms , P e .

[0090] In one embodiment, the human impedance model 6 is the human equivalent load model mentioned in the report of the international standard IEC 60601-1 for electrical equipment safety assessment.

[0091] In one embodiment, the plasma jet device includes a plasma jet generator 2 and a main body device, as Figure 3As shown, the main device includes a power supply 101 and a gas cylinder 301. The working gas in the gas cylinder 301 enters the plasma jet generator 2 after passing through a pressure reducing valve 302, a valve 304, and a gas flow meter 305.

[0092] In the present invention, the plasma jet device does not require an external large gas cylinder, achieving the portability of the inert gas plasma generation device.

[0093] The plasma jet generator 2 can adopt any plasma jet generator capable of generating a jet fluid plume 207. The position area part 10 is for placing the experimental equipment to be tested, not limited to the plasma jet generator in the embodiment, and other equipment to be tested can be placed in the area.

[0094] In one embodiment, as Figure 4 shown, the plasma jet generator 2 adopts a needle - ring DBD structure, including a stainless steel tube 202. The stainless steel tube 202 is arranged inside a hollow quartz tube 206. A copper ring 203 is provided below the quartz branch tube 206. A sealant 201 is filled in the gap between the upper part of the quartz tube 206 and the stainless steel tube 202. In one embodiment, a protective sleeve 204 is provided at the front end of the jet fluid plume 207 of the jet generator 2. The outer wall of the quartz tube 206 is wrapped with a nylon material as an insulating shell 205, improving the safety during testing. Among them, the stainless steel tube 202 with an outer diameter of 1.5 mm serves as the anode, and the copper ring 203 with a width of 5 mm and a thickness of 1 mm serves as the cathode grounded.

[0095] In one embodiment, the overall size of the plasma jet device is 347×300×145 mm, and the total weight is approximately 6 kg.

[0096] In one embodiment, the plasma jet generator 2 is about 180 mm long, and the diameter of the insulated part that can be held by hand is 12 mm.

[0097] The present invention takes into account both the instantaneous effect and the average effect during human contact; considering the instantaneous effect, an evaluation quantity for the safety of human contact with the jet fluid plume - specific pulse energy is proposed to measure whether human contact is safe during a single discharge pulse cycle; considering the average effect, an evaluation quantity for the safety of human contact with the jet fluid plume - root - mean - square current is proposed to measure whether a human is safe during the entire process of contacting the jet fluid plume.

Claims

1. A method for evaluating the electrical safety of human contact with a plasma jet, comprising the following steps: Step S01: Acquisition of the electrical characteristics of the plasma jet, and the acquisition of the electrical characteristics includes the acquisition of the discharge voltage and the current signal; Step S02: Acquisition of the current flowing through the human impedance model; Step S03: Calculating the effective value of the current flowing through the human body by Equation (1), and calculating the specific pulse energy by Equation (2): where I Prms is the effective current value, and i p is the instantaneous current value, T is the calculation period, and P e is the specific pulse energy, that is, the electrical energy absorbed by the unit resistance; t i is the single discharge current duration; Step S04: When the effective current value I prms and the specific pulse energy P e do not exceed the safety threshold, it is determined that the human contact is safe; otherwise, it is determined that the human contact is unsafe.

2. The method for evaluating the electrical safety of plasma jet in contact with human body according to claim 1, characterized in that: The effective current value is calculated for 1 s, P e Calculate the strongest discharge current pulse.

3. The method for evaluating the electrical safety of plasma jet human contact according to claim 1, wherein: The human body impedance model (6) is placed at different positions from the outlet of the plasma jet to be evaluated, for testing the presence or absence of the human body impedance model and the influence of different positions on I H and the jet fluid plume (207).

4. The method for evaluating the electrical safety of plasma jet human contact according to claim 3, wherein: Record the I of the human body load model at different distances H , and respectively calculate the effective value and specific impulse energy according to the calculation formulas of I Prms and P e . When both I Prms and P e are less than the safety threshold, the device to be evaluated achieves safe human contact at this distance.

5. The method for evaluating the electrical safety of plasma jet in contact with human body according to claim 4, wherein: According to the distance for achieving safe human contact, a protective sleeve (204) is provided at the front end of the plasma jet plume (207) of the plasma jet generator (2) to ensure that the human contact with the plasma plume is within a safe range.

6. The method for evaluating the electrical safety of plasma jet in contact with human body according to claim 3, wherein: According to the discharge equivalent circuit model and the human equivalent circuit model, calculate and determine the plasma plume resistance, and determine the range of the plume resistance values at the safe distance.

7. The method for evaluating the electrical safety of plasma jet in contact with human body according to claim 4, wherein: To achieve safe contact with the plasma jet, in addition to changing the distance, it is also possible to limit I by connecting a protection resistor with a resistance value not less than the equivalent body plume resistance calculated above in series on the high-voltage side. Prms and P e to achieve safe contact with the human body.

8. A plasma jet human contact electrical safety evaluation test platform, characterized in that: It includes a driving power supply (101), a digital oscilloscope (5), and a human body impedance model (6). A high-voltage probe (3) and a first current coil (4) are respectively connected to the digital oscilloscope (5). The plasma jet device to be evaluated is placed at the position area (10). The high-voltage probe (3) is connected to the high-voltage electrode of the plasma jet device to be evaluated to measure the high-voltage electrode voltage. The first current coil (4) is connected to the human body impedance model (6) to measure the current I flowing through the body plume and the human body impedance model. H； The human body impedance model (6) contacts the plasma jet body plume (207) through a metal sheet (601). It also includes a second current coil (8) and a third current coil (9) connected to the digital oscilloscope (5). The second current coil (8) is connected to the grounding electrode to measure the grounding electrode lead current I. G The third current coil (9) is arranged between the power supply (101) and the high-voltage electrode to measure the total current I passing through the high-voltage electrode. W The human body impedance model (6) is the human body equivalent load model mentioned in the report of the international standard IEC 60601-1 for electrical equipment safety assessment. The plasma jet device includes a plasma jet generator (2) and a main body device. The main body device includes a power supply (101) and a gas cylinder (301). The working gas in the gas cylinder (301) enters the plasma jet generator (2) after passing through a pressure reducing valve (302), a valve (304), and a gas flow meter (305).

9. The plasma jet human contact electrical safety evaluation test platform according to claim 8, characterized in that: The plasma jet generator (2) adopts a needle-ring DBD structure, including a stainless steel tube (202), the stainless steel tube (202) is arranged inside a hollow quartz tube (206), a copper ring (203) is provided below the quartz branch tube (206), and a sealant filling (201) is provided in the gap between the upper part of the quartz tube (206) and the stainless steel tube (202).

10. The plasma jet human contact electrical appliance safety evaluation test disk platform according to claim 9, characterized in that: The outer wall of the quartz tube (206) is wrapped with nylon material as an insulating shell (205).

Images