TWI592670B - Intelligent high voltage power supply equipment - Google Patents

Description

Insulation characteristic degradation method for intelligent high-voltage power supply equipment

The invention relates to a method for detecting insulation degradation, in particular to a cable line suitable for a power supply grid with existing transformers, which is convenient, time-saving, low-cost, re-powered and safe, and high-efficiency detection. Construction method.

Referring to Figures 1 to 3, the three-phase circuit 1 of the general grid system includes a three-phase transformer 10, wherein U _n represents the rated operating voltage between the opposite phases, U ₀ represents the rated operating voltage between ground and ground. Wherein, the relationship between U ₀ and U _n is as shown in the equation (1).

In general, the overvoltage tolerance range of the phase relative to the phase of the transformer 10 during normal operation is as shown in the high voltage power supply equipment of the high voltage power supply apparatus shown in FIG. 2, and the overvoltage tolerance of the cable lines 11, 12, and 13 is generally higher. Higher than the overvoltage tolerance of transformer 10. Once the cable 11 circuit of one of the phases has a single-phase ground fault due to insulation degradation, as shown in Figure 3, the other two healthy phase cables 12, 13 will withstand The maximum possible abnormal overvoltage of the maximum. Where Z _f represents the ground impedance when a single-phase earth fault occurs, and i _f represents the short-circuit fault current when a single-phase earth fault occurs.

Usually, the new high-voltage cable lines 11, 12, 13 will be tested for AC voltage and partial discharge on the cable lines 11, 12, 13 at the time of delivery. Once the test results meet the specifications, they are sent to the customer. End installation. Partial discharge (also known as partial discharge) electrical measurement method is a method for detecting partial discharge pulse current from the detection circuit. This method is easy to perform quantitative test and has high sensitivity, among which pulse current method The most widely used method is the measurement method recommended in the IEC-60270 partial discharge measurement standard published in December 2000 as shown in Annex 1. It measures the amount of discharge charge of the pulse current generated by partial discharge in units of pC (Pico-Coulomb).

In order to ensure the reliability of the power supply, both the Taipower company and the industrial users generally use the power cable instead of the bare overhead line for the power supply line. Although the power cable can be controlled quite well in today's manufacturing quality, there are many procedures that need to be applied to the site to make the cable actually perform as it should.

The reasons for the deterioration of the insulation properties of the cable include, inter alia, the defects and aging of the on-site construction, such as poor construction environment, uneven personnel training, incorrect work methods and rushing work.遂 瑕疵 瑕疵 瑕疵 瑕疵 遂 遂 遂 遂 遂 遂 遂 遂 遂 遂 遂 遂 遂 遂 遂 遂 瑕疵 瑕疵 瑕疵 瑕疵 瑕疵 瑕疵 瑕疵 瑕疵 瑕疵 瑕疵 瑕疵 瑕疵 瑕疵 瑕疵 瑕疵 瑕疵 瑕疵 瑕疵 瑕疵 瑕疵 瑕疵 瑕疵 瑕疵 瑕疵 瑕疵 瑕疵

For example, the IEEE P400.4/D6 document published in 2013, as shown in Annex II, has also begun to draft an off-line partial discharge detection specification. In recent years, many users in China have begun to introduce this type of off-line detection technology and apply it to the insulation degradation detection of high-voltage cables in the field.

At present, the cable performs on-site partial discharge detection method. The three important measurement parameters are Partial Discharge Inception Voltage (PDIV), Partial Discharge Extinction Voltage (PDEV) and partial discharge. Wherein, the partial discharge start voltage (PDIV) refers to the lowest voltage when the voltage applied to the cable is gradually increased from a lower value that is not measured to a partial discharge to a partial discharge in the cable. The partial discharge voltage (PDEV) refers to the voltage that is applied to the cable from a certain measurement to a higher value of the partial discharge, until the voltage of the repeated partial discharge is stopped in the cable. Under the normal operation of the cable, the normal operation detection curve 30 is as shown in Fig. 4. The voltages of the partial discharge start voltage (PDIV) and the partial discharge extinguishing voltage (PDEV) are higher than the rated operating voltage U between the system and the ground. ₀ . However, when the cable is partially discharged, if the partial discharge detection curve 31 is as shown in Fig. 5, if the voltage of the partial discharge extinguishing voltage (PDEV) is lower than the rated operating voltage U ₀ between the system and the ground, the cable is When the power is resumed again, it will be in an extremely dangerous state, so it is necessary to stop the power recovery immediately and take further repairs.

The off-line detection method shown in Annex II is basically based on the detection architecture of IEC-60270 shown in Annex 1, and uses the Sinusoidal Damped Alternating Current Voltage (DAC) as shown in Figure 6. ) 32 test power supply. The attenuated oscillating AC sine wave voltage generator (DAC) 32 is a part of the cable line 11, 12, 13 which is off-line using the special attenuated oscillating sinusoidal voltage signal 33 as shown in FIG. Discharge insulation degradation detection.

In addition, please refer to FIG. 8 , which is a schematic diagram of a pulse reflection method used by the DAC partial discharge detection system and its structure 34 for local discharge point positioning. If the length of the cable is l and it is assumed that a partial discharge occurs at the test end x , the pulse will propagate along the cable in two opposite directions, one of which After the time of equation (2) reaches the test end; and another pulse Propagating to the opposite end of the test end, and then transmitting to the test end after being reflected by the opposite end, and reaching the test end after the time of the equation (3). After two pulses according to a time difference of arrival △ t to calculate the position of the point of partial discharge, as shown in equation (4).

Where v is the pulse speed.

Therefore, the most characteristic feature of the attenuated oscillating AC sine wave voltage signal 33 used in the offline detection mode is that the partial discharge detection can be performed on the cable using a higher transient voltage, which not only has a good quantitative effect, but also can detect early. The position of the potential partial discharge point such as the terminal processing head or the indirect continuation end of the entire cable line is known, and the parameters such as the PDIV, the PDEV, and the partial discharge amount are known.

Finally, we will return to the actual surface of the actual electricity use site to discuss the blind spots and difficulties in the detection of partial discharge detection of the relevant high-voltage cable. The off-line detection method must stop the supply of the external power supply and detect the disconnection of the cable lines 11, 12, and 13 when detecting the cable lines 11, 12, and 13, resulting in the following defects. One: Since off-line inspection operations require disconnection, it is bound to cause the load equipment to be in a long-term shutdown state, which may seriously affect the production profit of the client factory; Second, even if the customer can arrange a power outage, when actually It is difficult to remove the cable that is connected to the side of the transformer and the switchboard, as shown in Annex III. Third, many customers are still conservative, and they may worry about connecting the cable back to the switchboard or When the terminal of the transformer is damaged, it may injure the inside of the cable terminal processing head, causing a second power outage accident when power is restored in the future, thereby expanding the power failure of the load device, and the loss of its customers is greater; The more the number of lines, the more likely it is to have the opportunity to injure the insulation characteristics of the terminal processing heads of the existing cable lines 11, 12, and 13. However, even with the accurate technology of off-line detection of DAC, there are still blind spots and difficulties in the above four points when performing partial discharge detection in actual power places.

In order to solve the lack of the traditional offline detection method in practical application, many customers retreat to conservatively only use the on-line detection method, because the online detection method does not need to remove the cable 11 and 12 13, can detect the partial discharge insulation degradation of the cable lines 11, 12, 13 in the state where the load device is not powered off, which is convenient and time-saving and does not seriously cause the customer investment cost and the loss of profit. The online detection method is detected by the principle of related electrical and physical phenomena generated by partial discharge, for example, when a partial discharge occurs at a certain position in the device, An electromagnetic field is generated to radiate outward from the partial discharge position, and the discharge signal is also transmitted to the exposed conductor outside through the conductor in the device, and is radiated outward by the stray capacitance in the space in the form of an electric field, and the pulse discharge current is also The energy is released through the grounding conductor and is accompanied by audible shockwave sound, light and heat, as shown in Figure 9. Wherein, A in the figure represents a partial discharge in the insulator; B represents an electromagnetic field radiated; C represents a voltage drop generated on the high voltage side; D represents an electric field via a stray capacitance to the earth; and E represents It is the current magnetic field that passes through the grounding wire.

The conventional on-line partial discharge detection structure 36 is shown in FIG. 10, and the detection method recommended by IEEE Std 400.3 published in 2006, which is shown in Annex IV, can be mainly referred to, wherein F and G represent capacitive senses in the figure. The detector, H, I represents an inductive sensor. For example, a Transient Earth Voltage Transducer (TEV) is a type of capacitive sensor, and a High Frequency Current Transformer (HFCT) is a type of inductive sensor. It can even be further used with ultrasonic type sensors or Ultra High Frequency (UHF) sensors to improve the ability to resist external noise, especially for the more serious noise. The environment is measured.

Generally speaking, there are four main factors affecting the insulation degradation of electrical equipment. One is: the deterioration of thermal stress, such as the ambient temperature of the running environment in the field and the current of the load, etc.; Second, the electrical stress caused by the abnormality of overvoltage Deterioration, such as various overvoltage anomalies that may be caused by an actual power system listed in page 17 of the IEC-60071-1 specification document published in March 2011, as shown in Annex 5; third: deterioration of mechanical stress, such as Mechanical stress, vibration or thermal expansion caused by short-circuit fault current; 4: Other deterioration caused by environmental factors such as moisture intrusion and air contact. However, in practical applications, the failure of cable equipment is usually caused by insulation degradation caused by the combination of these main factors.

However, the conventional on-line (also known as online live-electric) partial discharge detection technology uses the actual operating voltage value of the voltage of 0.95 U ₀ to 1.05 U _{0 when} the cable is at the city level. Although the online detection method has the advantages of convenient detection and no need for on-site cable disconnection, since the amount of partial discharge is essentially sensitive to voltage, if only the operating voltage value of 0.95 U ₀ to 1.05 U ₀ is used for detection, It is not easy to detect the lack of potential insulation degradation of the cable early.

As described above, the conventional online detection method has the inability to effectively detect the lack of serious insulation degradation of the cable early, and the conventional offline detection method has difficulty in application, high profit loss of potential factory production, and potential There will be additional damage to its existing insulation properties, so there are still room for improvement in the two known detection methods.

The object of the present invention is to provide a power supply network which is especially suitable for the cable line connecting the existing transformers, and the test power supply is connected to the low voltage side of the transformer, and the voltage is boosted by the transformer, thereby improving the test voltage of the cable. The inspection method can achieve a number of advantages such as convenient, time-saving, low-cost, re-powered and safe, and high-efficiency detection.

According to the foregoing objective, the present invention provides a method for detecting deterioration of insulation characteristics of a smart high-voltage power supply device, and is particularly suitable for detecting insulation degradation of a cable-connected power supply network with existing transformers, which includes the following steps: Step 1: Electricity Optionally connecting at least one cable to at least one side of the transformer; step 2: electrically connecting an external power source at the end of the cable away from the transformer; and step 3: electrically connecting at least one switch to the external power source and the transformer Step 4: electrically connecting a test power supply on the low voltage side of the transformer, the relative ground voltage of the test power supply is greater than the rated operating voltage of the system relative to the ground; Step 5: electrically connecting to the cable by using a first detecting device and checking whether the cable has insulation degradation of partial discharge.

Further, the waveform of the test power source is a voltage signal of a steady-state sine wave or a steady-state cosine wave, and the relative ground voltage of the test power source is greater than or equal to 1.1 times the relative rated operating voltage of the system.

Further, the frequency of the test power source is greater than or equal to the rated operating frequency of the system.

Further, the transformer is set as an oil transformer, or a dry transformer, or a die cast transformer, or a sulfur hexafluoride transformer.

Further, the first detecting device includes a first detecting device electrically connected to the cable, a first signal processor electrically connected to the first detecting device, and a first electrically connected to the first signal processor. The first computer data storage. Wherein, the first computer data storage has a first analysis software for analyzing whether the cable has partial discharge insulation degradation. The first detecting instrument is set as an ultrasonic type sensor, or an ultra high frequency sensor, or a capacitive sensor, or an inductive sensor.

Further, the inductive sensor is set as a high frequency current comparator.

Further, the capacitive sensor is configured as a transient ground voltage sensor.

Further, the ultrasonic type sensor is set as a sounding sensor.

The invention is characterized by:

1. The present invention improves the test voltage of the cable by connecting the test power supply on the low voltage side of the transformer, and then detects the first detection device which is popular in the online type, and the method can detect the power more efficiently and early. If the cable is seriously deteriorated, it can be repaired before the cable is seriously damaged, so as to avoid the fire caused by overvoltage or overcurrent in the damaged area, which may cause the explosion of the load device or even damage. Innocent, resulting in greater safety accidents and the risk of power outages in the factory, thereby achieving high efficiency detection and re-powering and safety.

2. When detecting by the first detecting device, once the cable is subjected to insulation degradation of a severe partial discharge, a high-performance and off-line Sinusoidal Damped Alternating Current Voltage (DAC) is used. The detection can be detected by using an off-line method that uses expensive instruments and has difficulty in disconnecting the wires without using each test, thereby reducing the cost and the difficulty of the application.

3. Since the low voltage side of the transformer is connected to a bare copper conductor, the side is easier to disconnect, and it is easy to connect the test power to the low voltage side of the transformer in the case of limited power outage time, and then online detection can be utilized. The first detecting device checks whether the cable has insulation degradation of partial discharge, thereby achieving convenience, time saving, and reducing the profit loss of the customer's production.

4. The new cable of this cable can be tested for insulation degradation by an off-line, attenuated AC sine wave voltage generator (DAC) before the transformer is connected, and the partial discharge insulation is degraded in the entire cable. The position and discharge situation can be found as the reference point for the next continuous tracking inspection. The reference method can be used to detect these potential reference points that have been abnormally discharged before the detection, thereby saving on-site maintenance. Manpower and time.

5. For the old cable, you can use this method to detect whether there is abnormal partial discharge in the cable, such as the terminal processing head or the intermediate indirect end. If the detection shows the change of the discharge trend amount in these places. When there is a serious change, the external power supply can be stopped, and then the offline detection method can be used for detection. The off-line detection equipment of the expensive instrument can be used without each test, thereby reducing the overall investment cost. Even in the detection, the position and discharge of other newly generated discharge points of the cable can be found as a reference point for the next continuous tracking inspection, thereby reducing the detection time.

6. The method for detecting deterioration of insulation characteristics of the intelligent high-voltage power supply device of the present invention can not only detect the cable of the new product in the power supply grid, but also can detect the cable of the existing old cable used in the power supply network. The invention is widely applicable.

[study]

1‧‧‧Three-phase circuit

10‧‧‧Transformers

11, 12, 13‧‧‧ cable

2‧‧‧ Typical overvoltage tolerance curve for high voltage power supply equipment

30‧‧‧Normal operation test curve

31‧‧‧Partial discharge detection curve

32‧‧‧Attenuated oscillating AC sine wave voltage generator

33‧‧‧Attenuated oscillating AC sine wave voltage signal

34‧‧‧Pulse reflection method and its structure

35‧‧‧Discharge phenomenon

36‧‧‧Online partial discharge detection structure

〔this invention〕

4‧‧‧Method for detecting deterioration of insulation characteristics of intelligent high-voltage power supply equipment

4a‧‧‧First detection block

4b‧‧‧Second test block

4c‧‧‧ third detection block

4d‧‧‧ fourth detection block

40, 41, 42, 43, 44, 45, 46, 47, 48, 49‧‧‧ cable

400, 410, 430, 431, 450, 451, 461, 462, 470, 471 ‧ ‧ connection

Indirect continuation in 401, 460‧‧

50, 51, 52, 53‧‧‧ transformers

60, 61‧‧‧ external power supply

70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 700, 701‧‧ ‧ switches

80, 81, 82, 83, 84‧‧‧ test power supply

800‧‧‧Voltage signal waveform

90‧‧‧First testing equipment

91‧‧‧First testing instrument

92‧‧‧First signal processor

93‧‧‧First computer data storage

94‧‧‧load

95‧‧‧Customer's own generator

Figure 1: Circuit diagram of a conventional three-phase circuit.

Figure 2: Schematic diagram of a typical overvoltage tolerance curve for a conventional high voltage power supply unit.

Fig. 3 is a circuit diagram showing a ground fault of a cable in a conventional three-phase circuit.

Figure 4: Schematic diagram of the normal operation detection curve of the conventional cable.

Figure 5: Schematic diagram of a partial discharge detection curve for a conventional cable.

Figure 6 is a circuit diagram of a conventionally oscillating AC sine wave voltage generator.

Figure 7: Schematic diagram of a conventionally oscillating AC sine wave voltage signal.

Figure 8 is a schematic diagram of a conventional pulse reflection method and its structure.

Figure 9: Schematic diagram of the phenomenon of conventional cable line discharge.

Figure 10: Circuit diagram of a conventional on-line partial discharge detection structure.

Figure 11 is a flow chart showing the steps of the present invention.

Fig. 12 is a circuit diagram showing a first embodiment of the present invention.

Figure 13 is a circuit diagram showing a second embodiment of the present invention.

Figure 14 is a schematic diagram of the steady state voltage signal waveform of the present invention.

Figure 15 is a circuit diagram showing a third embodiment of the present invention.

Figure 16-1 is a schematic diagram of the first block test of the third embodiment of the present invention.

Figure 16-2 is a schematic diagram of the second block test of the third embodiment of the present invention.

Figure 16-3 is a schematic diagram of the third block test of the third embodiment of the present invention.

Figure 16-4 is a schematic view showing the fourth block test of the third embodiment of the present invention.

The purpose, technical contents, features and effects achieved by the present invention will be more readily understood by the following description in conjunction with the accompanying drawings.

Please refer to the 11th to 14th drawings. The method for detecting the deterioration of the insulation characteristics of the intelligent high-voltage power supply equipment proposed in the present invention is particularly suitable for detecting the insulation degradation of the cable-connected power supply network with the existing transformers. The method for detecting the deterioration of the insulation characteristic of the intelligent high-voltage power supply device includes the following steps: Step 1: electrically connecting at least one cable 40 to at least one side of the transformer 50; and step 2: electrically connecting an external power source 60 The cable 40 is remote from the end of the transformer 50; Step 3: electrically connecting at least one switch 70 between the external power source 60 and the transformer 50; Step 4: electrically connecting a test power source 80 to the low voltage side of the transformer 50 The relative ground voltage of the test power source 80 is greater than the rated operating voltage of the system. As shown in the equation (5), U _text > U ₀ (5), where U _text represents the voltage relative to the test power source 80, U ₀ represents the rated operating voltage of the system relative to each other; and step 5: electrically connecting to the cable 40 by a first detecting device 90 and checking whether the cable 40 has partial discharge. Insulation is degraded.

According to the embodiment shown in FIG. 12, a switch 70 is electrically connected between the external power source 60 and the transformer 50, and the electrical connection between the switch 70 and the transformer 50 is sequentially connected. A cable line 42 is electrically connected between the external power source 60 and the switch 70. A switch 71 is electrically connected between the transformer 50 and a load 94. The switch 71 and the change A cable line 43 is electrically connected between the voltage switch 50 and a cable 44 is electrically connected between the switch 71 and the load 94.

In the embodiment shown in FIG. 13 , the external power source 60 and the transformer 50 are electrically connected to two switches 70 and 72. The switches 70 and 72 are electrically connected to each other. A cable line 42 is electrically connected between the switch 70 and the external power source 60, and a cable 45 is electrically connected between the switch 72 and the transformer 50. A switch 71 is electrically connected between the transformer 50 and the load 94. A cable 43 is electrically connected between the switch 71 and the transformer 50. A cable 44 is electrically connected between the switch 71 and the load 94.

The voltage signal waveform 800 of the test power supply 80 of the present invention can be applied to a steady state signal of a steady state sine wave or a steady state cosine wave in practical implementation, and in the embodiment of the present invention, a steady state sine wave is taken as an example, and The relative ground voltage of the test power source 80 used in this case is greater than the rated operating voltage of the system. For example, if the relative phase rated operating voltage U _n of a three-phase power supply system is 161 kV, the relative ground voltage U _{text of} the test power supply 80 in the present case is greater than or equal to the equation (6); if a three-phase power supply system is relatively The phase rated operating voltage U _n is 33 kV volts. In this case, the relative ground voltage U _{text of} the test power source 80 is greater than or equal to that shown in equation (7), and so on. In a preferred embodiment, the relative ground voltage of the test power supply 80 is greater than or equal to 1.1 times the relative rated operating voltage of the system. When the test power supply 80 is higher than the ground voltage U _text , the next time The time of re-detection can be pulled longer, so in a more preferred embodiment, the relative ground voltage of the test power supply 80 is between 1.3 and 1.5 times the relative nominal operating voltage of the system, but is not intended to limit the case.

The present invention improves the test voltage of the cable lines 40, 41, 42, 43, 44, 45 by connecting the test power source 80 to the low voltage side of the transformer 50, and then detecting the first detection device 90 in an online manner. The method can detect the serious insulation degradation of the cable more efficiently and early, and the actual operating voltage of the cable 40, 41, 42, _43, 44, 45 is 0.95 U ₀ to 1.05 U ₀ is very serious. Before the damage, it can be arranged for maintenance to avoid fires caused by over-voltage or over-current in the damaged area, which may cause unpredictable explosion of the electric load equipment, and even damage the innocent, resulting in greater safety accidents and factory power outages. Risk, thereby achieving high efficiency detection and re-energizing and safety, overcoming the conventional online detection method can not effectively detect the lack of serious insulation degradation early. The first detecting device 90 includes a first detecting device 91 electrically connected to the cable lines 40, 41, 42, 43, 44, 45, and a first signal processor electrically connected to the first detecting device 91. 92. A first computer data storage 93 electrically connected to the first signal processor 92. The first computer data storage 93 has a first analysis software (not shown) for analyzing whether the cable lines 40, 41, 42, 43, 44, 45 have partial discharge insulation degradation, and the first signal processor 92 With an oscilloscope as an application, the first analysis software can be in matlab, or C language, or C++ language, or Visual C++ language, but not limited thereto. Wherein, the first detecting instrument 91 can be applied by a technical means such as a capacitive sensor or an inductive sensor taught in IEEE Std 400.3 published in Annex IV in Annex IV, for example, a transient ground voltage sensor. (Transient Earth Voltage Transducer, TEV) is one type of capacitive sensor. High Frequency Current Transformer (HFCT) is one type of inductive sensor. It can even be further used with ultrasonic type sensors or Ultra High Frequency (UHF) sensors to improve the ability to resist external noise, especially for the more serious noise. Do the measurement under the environment. Among them, the ultrasonic type sensor can be set as an Acoustic Emission (AE), and the Acoustic Sensor (AE) belongs to a contact type detection.

More specifically, please refer to FIGS. 12 and 13 for illustration. The embodiment of the present invention is exemplified by a portion which is more susceptible to insulation degradation, but is not intended to limit the present invention, wherein each of the cable lines 40, 41 , 42, 43, 44, 45 are more prone to partial discharge insulation degradation in the place The connection end 400/410, 430, 431, 450, 451 of the piece to the line, or the intermediate indirect end 401 of the line. The first detecting device 91 of the first detecting device 90 is electrically connected to each of the connecting ends 400, 410, 430, 431, 450, after the low voltage side of the transformer 50 is electrically connected to the test power source 80. 451 or the intermediate indirect 401, after which the voltage change of each of the connecting ends 400, 410, 430, 431, 450, 451 or the intermediate indirect 401 is collected by the first signal processor 92, and thereafter passed through the first computer The first analysis software of the data storage 93 analyzes whether the voltage change of each of the connection terminals 400, 410, 430, 431, 450, 451 or the intermediate indirect terminal 401 has insulation degradation in which partial discharge occurs.

Further, when detecting by the first detecting device 90, once each of the connecting ends 400, 410, 430, 431, 450, 451 or the intermediate indirect end 401 is subjected to insulation degradation of a severe partial discharge, that is, some places When there is a serious change in the change in the amount of discharge trend, the external power supply can be stopped, and then the cable lines 40, 41, 42, 43 can be reused by a second high-performance off-line detection device (not shown). 44, 45, and more complete detection, no need to use more expensive instruments and offline detection methods that are difficult to remove each time, which can reduce the cost and difficulty of application, to improve the conventional offline Difficulties in implementation, high loss of production profitability, and damage to insulation properties at the end of the cable terminal treatment head. During the detection, each of the cable lines 40, 41, 42, 43, 44, 45 is removed, and each of the cable lines 40, 41, 42, 43, 44, 45 is electrically connected by the second detecting device and Each of the cable lines 40, 41, 42, 43, 44, 45 performs off-line partial discharge detection. After the disconnection is detected, the cable lines 40, 41, 42, 43, 44, 45 are reconnected, and thereafter, the cable lines 40, 41, and 42 can be detected by performing the pressure test through the steps of the method of the present invention. 43, 44, 45, effectively verify and ensure that the re-powering of each switch 70, 71, 72 on site is safe.

The second detecting device includes a second detecting device (not shown) electrically connected to the cable lines 40, 41, 42, 43, 44, 45, and a second detecting device electrically connected to the second detecting device. a signal processor (not shown), and a second computer data storage electrically connected to the second signal processor (not shown). The second detecting instrument is set as a continuous sinusoidal sinusoidal sinusoidal voltage generator (DAC), and the measuring structure of the continuous oscillating sinusoidal sinusoidal voltage generator (DAC) can be referred to Annex 1 or Annex II. The second signal processor is applied to an oscilloscope. The second computer data storage device has a second analysis software (not shown) for analyzing whether the cable wires 40, 41, 42, 43, 44, 45 have partial discharge insulation degradation, and the second analysis software can be matlab, Or C language, or C++ language, or Visual C++ language, but not limited to this. The second detecting device, the second signal processor, the second computer data storage device, and the second analysis software detecting action are respectively the first detecting device 91, the first signal processor 92, and the first computer data. The storage unit 93 and the first analysis software.

Further, in the embodiment of the present invention, the test power source 80 is electrically connected to the low voltage side of the transformer 50. Since the low voltage side of the transformer 50 is connected to a bare copper conductor, the side portion is easier to disconnect, and the test power source 80 is easily connected from the low voltage side of the transformer 50 when the power failure time is limited, and then the online power can be utilized. The first detecting device 90 of the type detected to check whether the connecting ends 400, 410, 430, 431, 450, 451 of the cable lines 40, 41, 42, 43, 44, 45 or the intermediate indirect end 401 have a partial portion The insulation of the discharge is deteriorated, thereby achieving the convenience, time saving, and reducing the profit loss of the customer's production, and improving the difficulty of re-disassembling the cable to be tested, and failing to perform effective detection in the case of limited power outage time.

In general, the transformer is designed such that its rated magnetic flux and the applied voltage and frequency are closely related to each other, as shown in equation (8) or equation (9). among them, Represented as the magnetic flux of the transformer, f _n represents the frequency of the transformer.

among them, Represented as the magnetic flux of the transformer, V ₁ represents the applied voltage on the low voltage side of the transformer, N ₁ represents the number of turns of the low side winding, and f represents the frequency of the applied voltage.

In order to not damage the core of the transformer at the time of the test, assume or The value is fixed. Under the condition that the voltage U _n or V _{1 is} increased, the frequency f _n or f must be increased at the same time to avoid the magnetic flux of the transformer. or The original rated design value. In order to achieve this safety purpose, the frequency of the test power supply 80 is further set to be greater than or equal to the rated operating frequency of the system. For example, if the rated operating frequency of the system is 50 Hz, the frequency of the test power supply 80 Greater than or equal to 50 Hertz (Hz), if the rated operating frequency of the system is 60 Hertz (Hz), then the frequency of the test power supply 80 is greater than or equal to 60 Hertz (Hz), and so on. Thereby, it is possible to detect not only the insulation degradation of the partial discharge of the cable wires 40, 41, 42, 43, 44, 45 by the present method, but also the damage of the transformer 50 itself. Wherein, in the embodiment of the present invention, the transformer 50 is set as an oil type transformer, or a dry type transformer, or a die-cast type transformer, or a sulfur hexafluoride transformer, but is not limited thereto.

The present invention is particularly suitable for insulation degradation detection of the cable wires 40, 41, 42, 43, 44, 45 in a 345 kV cable, or a 161 kV cable, or a 69 kV cable or a 33 kV cable or a 22.8 kV cable. Since the cables of the high-voltage power supply system loops such as 345kV cable, 161kV cable, and 69kV cable are installed and tested in the new construction section, it is difficult to remove the cables after they are connected to the switchboard or transformer. As shown in Annex III, it is difficult to conduct effective maintenance inspections in the future. In addition, some 33kV cables and 22.8kV cables are powered by plug-in cable heads that use gas-insulated switchgear (GIS). These places can be used to disassemble and install cable terminations on both sides. The insulation property is detected, but it is very time-consuming and professional, which leads to inconvenience in construction. If the construction is inadvertent, it will cause an electrical insulation fault to be accelerated in the future. Here, 345kV cable, or 161kV cable, or 69kV cable or The cable of the high-voltage power supply system loop of 33kV cable or 22.8kV cable has the difficulty of requiring additional disconnection and re-powering, so a new inspection method is proposed in this case to solve the conventional missing.

Further, the new cable 40, 41, 42, 43, 44, 45 can be connected to the cable through a conventional off-line attenuated AC sine wave voltage generator (DAC) before the transformer 50 is connected. 40, 41, 42, 43, 44, 45 for partial discharge insulation degradation detection, and through the calculation of equations (2) ~ (4) to find the discharge point position and discharge situation of the entire cable with partial discharge insulation degradation Come out as the reference point for the next continuous tracking check, such as the connecting ends 400, 410, 430, 431, 450, 451 or the indirect continuation 401, and then use the method to detect when the maintenance is performed regularly. These potential reference points have been abnormally discharged, thereby saving on-site maintenance manpower and time.

For the old cable 40, 41, 42, 43, 44, 45, the cable 40, 41, 42, 43, 44, 45 can be detected by the method to detect abnormal partial discharge. If it is found that the change of the discharge trend amount of the terminal processing head or the intermediate indirect end of the cable 40, 41, 42, 43, 44, 45 is severely changed, the external power supply can be stopped, and then the offline detection method is used to detect The off-line inspection equipment of the more expensive DAC instruments is not required for each inspection, thereby reducing the overall investment cost. Similarly, the positions of the entire cable having the discharge point can be found through the calculation of equations (2) to (4), such as the connection terminals 400, 410, 430, 431, 450, 451 or the indirect End 401 is used as a reference point for the next continuous tracking check, thereby reducing the detection time.

The method for detecting deterioration of insulation characteristics of the intelligent high-voltage power supply device of the present invention can not only detect the cable of the new product in the power supply grid, but also can use the invention to detect the existing cable in the power supply network. The invention is widely applicable.

Please refer to Figure 15 for an example of the power supply process from Taipower to the customer and the current two-loop power supply system. An external power supply 61 provided by Taipower is used. The 161kV high-voltage cable 46 is electrically connected to the high-voltage side of the two transformers 51, and the low-voltage side of each of the transformers 51 is electrically connected to a transformer 52 via a 33kV high-voltage cable 47, respectively. Transformer 52 is in turn electrically coupled to complex load 94 via a plurality of lower volt cable lines 48, respectively. Three switches 73 are disposed in each of the cable lines 46 between the external power source 61 and each of the transformers 51, and each of the cables 51 between the transformers 51 and each of the transformers 52 is provided with two Switches 74, 75 are provided with a plurality of switches 76, 77 in each of the cable lines 48 between each of the transformers 52 and each of the loads 94. Optionally, a power generator 56 electrically connected to each of the cable wires 46 and each of the transformers 51 of the transformer 51 may be provided as a backup power source, and the customer's internal generator 95 and each of the cables may be provided. A transformer 53 is electrically connected between the transformer 53 and the generator 95 provided by the customer. A switch 78 is disposed between the transformer 53 and each of the cables 46. The transformer is provided. A cable 49 is electrically connected to the switch 79. Between each loop, two switches 700, 701 are provided for mutual switching, so that a single loop abnormality is avoided and the load 94 cannot be normally powered.

Referring to Figure 16-1, when the cable ray of the right side of the 161kV high voltage is to be tested for partial discharge insulation degradation, the test power source 81 is electrically connected to the low voltage side of the transformer 51 through the method of the present invention. A detecting block 4a is thereafter detected by the first detecting device 90 whether each of the connecting ends 461, 462 or the intermediate indirect end 460 has insulation degradation in which partial discharge occurs. For the connection, as shown in Figure 16-2, when the cable ray of the left side of the 161kV high voltage is to be tested for partial discharge insulation degradation, the test power source 82 is electrically connected to the low voltage side of the transformer 51 through the method of the present invention, such as The second detecting block 4b is thereafter detected by the first detecting device 90 whether each of the connecting ends 461, 462 or the intermediate indirect end 460 has insulation degradation in which partial discharge occurs.

For the connection, please refer to Figure 16-3. When the cable line 47 with a high voltage of 33kV on the right side is to be tested for partial discharge insulation degradation, the test power supply 83 is electrically connected to the low voltage side of the transformer 52 through the method of the present invention, such as a third detection block 4c, after which each of the detection devices 90 detects each Whether the connection end 470, 471 or the intermediate indirect end has insulation degradation in which partial discharge occurs. Referring to Figure 16-4, when the cable line 47 with a high voltage of 33kV on the left side is to be tested for partial discharge insulation degradation, the test power source 84 is electrically connected to the low voltage side of the transformer 52 through the method of the present invention, such as The fourth detecting block 4d is thereafter detected by the first detecting device 90 whether or not each of the connecting ends 470, 471 or the intermediate indirect end has insulation degradation in which partial discharge occurs. This is also the case if it is to be detected whether or not the cable 49 electrically connected to the internal generator 95 of the customer has insulation degradation of partial discharge.

In summary, the present invention can achieve the following characteristics:

1. The present invention improves the test voltage of the cable lines 40, 41, 42, 43, 44, 45 by connecting the test power source 80 to the low voltage side of the transformer 50, and then utilizing the first detection device 90 of the conventional online type. Convenience to detect, this method can detect the more serious insulation degradation of the cable more efficiently, and then arrange the maintenance before the cable 40, 41, 42, 43, 44, 45 is very seriously damaged. To avoid fires caused by over-voltage or over-current in the damaged area, which may cause the explosion of the load 94, and even damage the flaws, resulting in a greater safety accident and the risk of power outages in the factory, thereby achieving high efficiency detection and re-powering Safe effect.

2. When detecting by the first detecting device 90, once the cable lines 40, 41, 42, 43, 44, 45 are deteriorated by the insulation of the severe partial discharge, the high-efficiency energy such as the damped AC sine wave voltage generator is reused ( The second detecting device of the DAC detects the off-line detection method which uses a more expensive DAC instrument and has difficulty in disconnecting the line without detecting each time, thereby reducing the cost and the difficulty of the application.

3. Since the low voltage side of the transformer 50 is connected to a bare copper conductor, the side portion is easier to disconnect, and the test power source 80 is easily connected to the low voltage side of the transformer 50 in the case of limited power outage time, and can be utilized thereafter. The first detecting device 90 of the conventional online detection detects the cable Whether the wires 40, 41, 42, 43, 44, 45 have partial discharge insulation degradation, thereby achieving convenience, time saving, and reduction in profitability of customer production.

4. The new cable 40, 41, 42, 43, 44, 45 can be passed through the second detecting device of the offline DAC to the cable 40, 41, 42, 43, 44 before the transformer 50 is connected. 45 to do accurate insulation degradation detection, and find all the positions and discharges of the partial cable insulation degradation in the entire cable, as the reference point for the next continuous tracking inspection, the first method can be used to detect There are reference points for these abnormal discharges, thereby saving the working time of regular maintenance.

5. For the old cable wires 40, 41, 42, 43, 44, 45, it is also possible to first detect whether the cable wires 40, 41, 42, 43, 44, 45 have abnormal partial discharge by using the method. Once the detection shows that there is a serious change in the change of the discharge trend amount in these places, the external power supply can be stopped, and then the offline detection method is used for detection, and the off-line detection of the expensive DAC instrument is not required for each detection. Equipment, which can reduce the overall investment cost. Even when detecting, the entire cable can be re-discovered for use as a reference point for the next continuous tracking check, thereby reducing the detection time. Moreover, when the cable is reconnected, the cable test can be performed through the steps of the method of the present invention to effectively verify and ensure the smooth operation of the site.

6. The method for detecting the deterioration of the insulation characteristic of the intelligent high-voltage power supply device of the present invention can not only detect the cable of the new product in the power supply grid, but also can use the present invention in the power supply network to the existing cable. The detection makes the invention widely applicable, effectively reduces the dead angle of the insulation degradation inspection work of the existing high-voltage cable, and improves the reliability of the power consumption of the factory.

The foregoing is only a preferred embodiment of the present invention, which is intended to be understood by those skilled in the art and is not intended to limit the scope of the present invention. Equivalent variations or modifications of the shapes, configurations and features are intended to be included within the scope of the present invention.

40, 41, 42, 43, 44‧‧‧ cable

400, 410, 430, 431‧‧‧ connectors

Indirect continuation in 401‧‧

50‧‧‧Transformers

60‧‧‧External power supply

70, 71‧‧ ‧ switch

80‧‧‧Test power supply

90‧‧‧First testing equipment

91‧‧‧First testing instrument

92‧‧‧First signal processor

93‧‧‧First computer data storage

94‧‧‧load

Claims (8)

The invention relates to a method for detecting insulation characteristic degradation of a smart high-voltage power supply device, which is particularly suitable for detecting insulation degradation of a cable power supply network with existing transformers, which comprises the following steps: Step 1: Electrically connecting at least one cable line At least one side of a transformer; step 2: electrically connecting an external power source at an end of the cable away from the transformer; step 3: electrically connecting at least one switch between the external power source and the transformer; step 4: electrical Connecting a test power source on a low voltage side of the transformer, the relative ground voltage of the test power source is greater than a rated operating voltage of the system; and step 5: electrically connecting to the cable line by using a first detecting device and checking whether the cable line is Insulation degradation with partial discharge. The method for detecting deterioration of insulation characteristics of a smart high-voltage power supply device according to claim 1, wherein the waveform of the test power source is a steady-state sine wave or a steady-state cosine wave voltage signal, and a relative ground voltage of the test power source Greater than or equal to 1.1 times the relative rated operating voltage of the system. The method for detecting deterioration of insulation characteristics of a smart high-voltage power supply device according to claim 1 or 2, wherein the frequency of the test power source is greater than or equal to a rated operating frequency of the system. For example, the method for detecting deterioration of insulation characteristics of a smart high-voltage power supply device as described in claim 1 or 2, wherein the transformer is an oil-type transformer, or a dry-type transformer, or a die-cast transformer, or hexafluoride Sulfur transformer. The method for detecting deterioration of insulation characteristics of a smart high-voltage power supply device according to claim 1 or 2, wherein the first detecting device comprises a first detecting device electrically connected to the cable, and an electrical property. a first signal processor connected to the first detecting device and a first computer data storage device electrically connected to the first signal processor; wherein the first computer data storage device has an analysis of whether the cable has a partial discharge The first analysis software for insulation degradation; the first detection instrument is set as an ultrasonic type sensor, or an ultra high frequency sensor, or a capacitive sensor, or an inductive sensor. The method for detecting deterioration of insulation characteristics of a smart high-voltage power supply device according to claim 5, wherein the inductive sensor is a high-frequency current comparator. The method for detecting deterioration of insulation characteristics of a smart high-voltage power supply device according to claim 5, wherein the capacitive sensor is configured as a transient ground-to-ground voltage sensor. The method for detecting deterioration of insulation characteristics of the intelligent high-voltage power supply device according to claim 5, wherein the ultrasonic type sensor is set as a sounding sensor.