Telemetering loop, measurement and control device and telemetering method

Abstract

The invention relates to the field of measurement and control, and mainly discloses a telemetering loop, a measurement and control device and a telemetering method.The telemetering loop comprises a PT terminal box, the PT terminal box is connected with the input ends of a Ua mutual inductor, a Ub mutual inductor and a Uc mutual inductor in line measurement and control through a Ua line, a Ub line and a Uc line respectively, and the output ends of the Ua mutual inductor, the Ub mutual inductor and the Uc mutual inductor are connected with the PT terminal box through a Un line. The Ua line, the Ub line and the Uc line are connected to the Un line to form a loop, the Un line serves as a common reference point, it can be ensured that the measurement of each phase voltage has a common reference point, and therefore the accuracy and stability of measurement are improved. By switching different positions of the rotary switch, different voltage signal paths can be flexibly selected, line voltage and phase voltage measurement requirements during normal operation are met, and more comprehensive diagnosis information is provided during fault analysis.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of measurement and control, and in particular to a telemetry loop, a measurement and control device, and a telemetry method. BACKGROUND

[0002] The measurement and control cabinet can measure and monitor the electrical parameters such as current, voltage, power, and frequency of the line in real time, and provide accurate data support for the stable operation of the power system. For example, by monitoring the current size, the load condition of the line can be determined; according to the voltage value, it can ensure that the electrical equipment works in the appropriate voltage range.

[0003] In a three-phase power system, most of the line measurement and control in the measurement and control device directly monitor the three-phase power, without providing a reference voltage, so that the measured phase voltage is not accurate enough, and the existing measurement and control device cannot realize the switching of line voltage measurement and phase voltage measurement, which makes it difficult to provide more comprehensive diagnostic information when analyzing faults. SUMMARY

[0004] Therefore, the technical problem to be solved by the present application is that the measured phase voltage is not accurate enough, and the switching of line voltage measurement and phase voltage measurement cannot be realized.

[0005] The above technical problem is solved by the following technical scheme: the present application provides a telemetry loop, which comprises,

[0006] a PT terminal box, which is connected to the input ends of Ua, Ub, and Uc transformers in the line measurement and control through Ua, Ub, and Uc lines respectively;

[0007] The output ends of the Ua, Ub, and Uc transformers are connected to the PT terminal box through Un lines;

[0008] Among them, the opening and closing of the Ua, Ub, and Uc lines is controlled by a rotary switch.

[0009] In a preferred embodiment of the telemetry loop described in the present application: the rotary switch comprises contact one, contact two, contact three, contact four, contact five, and contact six;

[0010] The contact one and the contact two are connected to the Ua line, the contact three and the contact four are connected to the Ub line, and the contact five and the contact six are connected to the Uc line.

[0011] In a preferred embodiment of the telemetry loop described in the present application: a Uo transformer is arranged in the line measurement and control, the input end of the Uo transformer is connected to the PT terminal box through a Uo line, the output end of the Uo transformer is connected to a Uon line, and the Uon line is connected to the Un line.

[0012] In a preferred embodiment of the telemetry loop described in the application: a CT terminal box is further included, the CT terminal box is connected with the input end of the Ia mutual inductor, Ib mutual inductor and Ic mutual inductor in the line monitoring and control through the Ia line, Ib line and Ic line respectively, the output end of the Ia mutual inductor, Ib mutual inductor and Ic mutual inductor is connected with the Ian line, Ibn line and Icn line respectively, the Ian line is connected with the Ibn line, the Ibn line is connected with the Icn line, and the Ian line, Ibn line or Icn line is connected with the CT terminal box.

[0013] In a preferred embodiment of the telemetry loop described in the application: an Io mutual inductor is arranged in the line monitoring and control, the input end of the Io mutual inductor is connected with the CT terminal box through the Io line, and the output end of the Io mutual inductor is connected with the CT terminal box through the Ion line.

[0014] The application provides a measuring and controlling device, which comprises a cabinet body, the line monitoring and control is arranged in the cabinet body, the line monitoring and control comprises a Ua mutual inductor, Ub mutual inductor, Uc mutual inductor, Uo mutual inductor, Ia mutual inductor, Ib mutual inductor, Ic mutual inductor and Io mutual inductor, and the line monitoring and control is connected with a PT terminal box and a CT terminal box.

[0015] The application provides a telemetry method of a measuring and controlling device, which comprises the following steps:

[0016] S1: the line monitoring and control receives the phase voltage signals and zero sequence voltage signals transmitted by the PT terminal box and the phase current signals and zero sequence current signals transmitted by the CT terminal box;

[0017] S2: the line voltage, phase voltage, current effective value, power, power factor and frequency are calculated according to the collected voltage and current signals;

[0018] S3: the operation state of the power system is monitored in real time, and it is judged whether overload, short circuit or grounding fault occurs.

[0019] In a preferred embodiment of the telemetry method of the measuring and controlling device described in the application: in step S1, the line monitoring and control receives the phase voltage signals from the PT terminal box through the Ua line, Ub line and Uc line, receives the zero sequence voltage signal through the Uo line, receives the phase current signals from the CT terminal box through the Ia line, Ib line and Ic line, and receives the zero sequence current signal through the Io line.

[0020] In a preferred embodiment of the telemetry method of the measuring and controlling device described in the application: in step S2, the line monitoring and control performs preliminary processing on the collected phase voltage signals and zero sequence voltage signals, and performs preliminary processing on the collected phase current signals and zero sequence current signals.

[0021] The line measurement and control device converts the processed phase voltage signals, zero sequence voltage signals, phase current signals and zero sequence current signals into digital signals;

[0022] The line voltage, phase voltage, current effective value, power, power factor and frequency are calculated according to the converted digital signals.

[0023] In a preferred embodiment of the telemetry method of the measurement and control device, in step S3, the line measurement and control device monitors the operation state of the power system in real time through the PT terminal box and the CT terminal box, and when the monitored voltage or current exceeds the preset threshold value, it is determined that the system may have an overload or short circuit fault, and when the monitored zero sequence voltage or zero sequence current exceeds the preset threshold value, it is determined that the system may have a ground fault;

[0024] When a system fault is detected, the measurement and control device sends an alarm signal and takes corresponding protection measures according to the preset protection logic.

[0025] The beneficial effects of the present application are that by connecting the Ua line, Ub line and Uc line to the Un line to form a loop, the Un line serves as a common reference point, which can ensure that the measurement of each phase voltage has a common reference point, thereby improving the accuracy and stability of the measurement;

[0026] When line voltage needs to be measured, the rotary switch is switched to the corresponding position to transmit the two-phase voltage signals of the PT terminal box to the measurement and control device, and the measurement and control device calculates the line voltage according to the received two-phase voltage signals, and when phase voltage needs to be measured, the rotary switch is switched to the corresponding position to transmit a phase voltage signal of the PT terminal box and the neutral point to the measurement and control device through the rotary switch, and the measurement and control device directly measures the voltage value of the phase voltage relative to the neutral point;

[0027] The rotary switch can flexibly select different voltage signal paths by switching different positions, meeting the line voltage and phase voltage measurement requirements during normal operation, and providing more comprehensive diagnostic information during fault analysis. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings of the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below only relate to some embodiments of the present application, but not limit the present application. Among them:

[0029] Figure 1 Fig. 1 shows a connection diagram of the PT terminal box and the line measurement and control device;

[0030] Figure 2 Fig. 2 shows a connection diagram of the CT terminal box and the line measurement and control device;

[0031] Figure 3A layout of the measurement and control device is shown.

[0032] Figure 4 A flow chart of a telemetry method of the measurement and control device is shown. DETAILED DESCRIPTION

[0033] In order for those skilled in the art to better understand the present application, the present application will be described in further detail below with reference to specific embodiments and accompanying drawings.

[0034] The terms used in the present application are those general terms currently widely used in the art in consideration of the functions related to the present application, but the terms can be changed according to the intention of those skilled in the art, precedents, or new technology in the art. Also, specific terms can be selected by the applicant, and in this case, the detailed meanings thereof will be described in the detailed description of the present application. Therefore, the terms used in the specification should not be understood as simple names, but based on the meanings of the terms and the overall description of the present application.

[0035] REFERENCE Figure 1 The present embodiment provides a telemetry loop, including a PT terminal box 100, a line measurement and control 200, and a rotary switch 300.

[0036] The PT terminal box 100 is connected to the input terminals of the Ua, Ub, and Uc transformers 201, 202, and 203 in the line measurement and control 200 through the Ua, Ub, and Uc lines 101, 102, and 103, respectively. The output terminals of the Ua, Ub, and Uc transformers 201, 202, and 203 are connected to the PT terminal box 100 through the Un line 104. The opening and closing of the Ua, Ub, and Uc lines 101, 102, and 103 are controlled by the rotary switch 300.

[0037] The PT terminal box 100 is a terminal box of a voltage transformer, which is used to convert the line voltage into a signal suitable for measurement by the measurement and control device, and connects the voltage transformer to the measurement and control device through the terminal box. The voltage transformer is installed on a high-voltage transmission line, and its primary side is directly connected to the high-voltage line for sensing the voltage on the high-voltage line. The secondary side of the voltage transformer converts the sensed high-voltage into a low-voltage signal, which is suitable for measurement by the measurement and control device. The output of the secondary side is connected to the PT terminal box 100 through a cable. The PT terminal box 100 is a centralized connection point for the output of the secondary side of the voltage transformer. In the present application, the PT terminal box 100 is connected to the input terminals of the Ua, Ub, and Uc transformers 201, 202, and 203 in the measurement and control device through the Ua, Ub, and Uc lines 101, 102, and 103, respectively.

[0038] The cable extends from the PT terminal box 100 to the measuring and control device, transmitting voltage signals to the input terminals of the measuring and control device. Inside the measuring and control device, these voltage signals are input to the corresponding Ua transformer 201, Ub transformer 202, and Uc transformer 203 through the Ua line 101, Ub line 102, and Uc line 103, respectively. The Ua transformer 201, Ub transformer 202, and Uc transformer 203 inside the measuring and control device further process these signals, converting them into signals suitable for measurement by the measuring and control device. The processed signals can be received by the measuring and control device and used for voltage measurement and display. After receiving the voltage signals, the measuring and control device performs amplification, filtering, and analog-to-digital conversion, converting the analog signals into digital signals. The measuring and control device calculates the voltage value and displays it on the panel.

[0039] Through the above steps, the voltage signals are transmitted from the PT terminal box 100 to the measuring and control device and ultimately measured and processed by the measuring and control device. This ensures that the voltage measurement of the power system is both safe and accurate.

[0040] By connecting the Ua line 101, Ub line 102, and Uc line 103 to the Un line 104 to form a loop, the influence of external electromagnetic interference can be reduced. Moreover, the Un line 104 as a common reference point can ensure that the measurement of each phase voltage has a common reference point, thereby improving the accuracy and stability of the measurement. If the Ua line 101 is not connected to the Un line 104 to form a loop, but is directly connected to the output of the Ua transformer 201 and the PT terminal box 100 to form a loop, it may cause the measurement loop to be unstable and susceptible to interference.

[0041] In a three-phase system, the Un line 104 as a neutral point has a stable potential close to zero. Referring to this neutral point for the measurement of each phase voltage can ensure that the measurement signal has a uniform reference voltage. Without a common reference point, the measurement of each phase voltage may be affected by other factors in the system, such as load changes, system faults, etc., resulting in unstable measurement potential. The stability of the neutral point helps to reduce such fluctuations and provide more reliable measurement results.

[0042] The rotary switch 300 includes contact one 301, contact two 302, contact three 303, contact four 304, contact five 305, and contact six 306.

[0043] Among them, the contact one 301 and the contact two 302 are connected to the Ua line 101, the contact three 303 and the contact four 304 are connected to the Ub line 102, and the contact five 305 and the contact six 306 are connected to the Uc line 103.

[0044] The contact one 301, the contact three 303 and the contact five 305 can be opened or closed to control the connection of the Ua line 101, the Ub line 102 and the Uc line 103, the Ua line 101 is used to transmit the A-phase voltage signal, the Ub line 102 is used to transmit the B-phase voltage signal, and the Uc line 103 is used to transmit the C-phase voltage signal.

[0045] When it is needed to measure the line voltage, the contact one 301 and the contact three 303 of the rotary switch 300 are closed. The A-phase voltage signal of the PT terminal box 100 is transmitted to the input end of the Ua transformer 201 through the contact one 301 and the contact two 302, the B-phase voltage signal of the PT terminal box 100 is transmitted to the input end of the Ub transformer 202 through the contact three 303 and the contact four 304, and the line voltage is calculated by the measuring and control device according to the received two-phase voltage signals.

[0046] The contact one 301 and the contact five 305 of the rotary switch 300 are closed. The A-phase voltage signal of the PT terminal box 100 is transmitted to the input end of the Ua transformer 201 through the contact one 301 and the contact two 302, the C-phase voltage signal of the PT terminal box 100 is transmitted to the input end of the Uc transformer 203 through the contact five 305 and the contact six 306, and the line voltage is calculated by the measuring and control device according to the received two-phase voltage signals.

[0047] The contact three 303 and the contact five 305 of the rotary switch 300 are closed. The B-phase voltage signal of the PT terminal box 100 is transmitted to the input end of the Ub transformer 202 through the contact three 303 and the contact four 304, the C-phase voltage signal of the PT terminal box 100 is transmitted to the input end of the Uc transformer 203 through the contact five 305 and the contact six 306, and the line voltage is calculated by the measuring and control device according to the received two-phase voltage signals.

[0048] When it is needed to measure the phase voltage, the contact one 301 of the rotary switch 300 is closed, the A-phase voltage signal of the PT terminal box 100 is transmitted to the input end of the Ua transformer 201 through the contact one 301 and the contact two 302, the A-phase voltage signal of the PT terminal box 100 and the neutral point are transmitted to the measuring and control device through the Ua line 101 and the Un line 104, and the voltage value of the phase voltage relative to the neutral point is directly measured by the measuring and control device.

[0049] The contact three 303 of the rotary switch 300 is closed, the B-phase voltage signal of the PT terminal box 100 is transmitted to the input end of the Ub transformer 202 through the contact three 303 and the contact four 304, the B-phase voltage signal of the PT terminal box 100 and the neutral point are transmitted to the measuring and control device through the Ub line 102 and the Un line 104, and the voltage value of the phase voltage relative to the neutral point is directly measured by the measuring and control device.

[0050] When the line voltage and the phase voltage are measured simultaneously, the contact one 301, the contact three 303 and the contact five 305 are closed.

[0051] When the line voltage and the phase voltage are measured simultaneously, the contact one 301, the contact three 303 and the contact five 305 are closed.

[0052] The A-phase voltage signal of the PT terminal box 100 is transmitted to the input end of the Ua transformer 201 through the contact one 301 and the contact two 302, and the B-phase voltage signal is transmitted to the input end of the Ub transformer 202 through the contact three 303 and the contact four 304. The line voltage Uab is calculated by the control device according to the received A-phase and B-phase voltage signals.

[0053] The B-phase voltage signal of the PT terminal box 100 is transmitted to the input end of the Ub transformer 202 through the contact three 303 and the contact four 304, and the C-phase voltage signal is transmitted to the input end of the Uc transformer 203 through the contact five 305 and the contact six 306. The line voltage Ubc is calculated by the control device according to the received B-phase and C-phase voltage signals.

[0054] The C-phase voltage signal of the PT terminal box 100 is transmitted to the input end of the Uc transformer 203 through the contact five 305 and the contact six 306, and the A-phase voltage signal is transmitted to the input end of the Ua transformer 201 through the contact one 301 and the contact two 302. The line voltage Uca is calculated by the control device according to the received C-phase and A-phase voltage signals.

[0055] The A-phase voltage signal of the PT terminal box 100 is transmitted to the input end of the Ua transformer 201 through the contact one 301 and the contact two 302, and the neutral point is connected to the output end of the Ua transformer 201 through the Un line 104. The phase voltage Ua is calculated by the control device according to the received A-phase voltage signal and the neutral point voltage.

[0056] The B-phase voltage signal of the PT terminal box 100 is transmitted to the input end of the Ub transformer 202 through the contact three 303 and the contact four 304, and the neutral point is connected to the output end of the Ub transformer 202 through the Un line 104. The phase voltage Ub is calculated by the control device according to the received B-phase voltage signal and the neutral point voltage.

[0057] The C-phase voltage signal of the PT terminal box 100 is transmitted to the input end of the Uc mutual inductor 203 through the contact five 305 and the contact six 306, and the neutral point is connected to the output end of the Uc mutual inductor 203 through the Un line 104. The control device calculates the phase voltage Uc according to the received C-phase voltage signal and the neutral point voltage.

[0058] When the contact one 301, the contact three 303 and the contact five 305 are all closed, the control device can simultaneously measure the line voltage and the phase voltage of the three phases, and realize comprehensive monitoring of the voltage state of the power system.

[0059] Through the setting of the rotating switch 300, the control device can flexibly adapt to different measurement requirements, and provide strong support for the stable operation and fault analysis of the power system.

[0060] The line control device 200 is provided with a Uo mutual inductor 204, the input end of the Uo mutual inductor 204 is connected to the PT terminal box 100 through the Uo line 105, and the output end of the Uo mutual inductor 204 is connected with the Uon line 106, and the Uon line 106 is connected with the Un line 104.

[0061] The input end of the Uo mutual inductor 204 is connected to the output end of the open delta winding of the PT terminal box 100 through the Uo line 105, for receiving the zero sequence voltage signal. The output end is connected with the Un line 104 through the Uon line 106, forming a complete measurement loop, ensuring that the signal can be accurately measured by the control device.

[0062] The Uo mutual inductor 204 is connected to the output end of the open delta winding of the PT terminal box 100. The function of the open delta winding is to provide the zero sequence voltage signal. When the three-phase voltage is balanced, the output voltage of the open delta winding is close to zero, and when the ground fault occurs, the output voltage of the open delta winding will rise, which is the zero sequence voltage.

[0063] The Uon line 106 is connected with the Un line 104, ensuring the consistency of the measurement reference. The Uo line 105 serves as the neutral line, providing a stable reference potential, so that the control device can measure the zero sequence voltage based on a unified reference point, improving the accuracy and stability of the measurement.

[0064] The Uo mutual inductor 204 is used to detect the zero sequence voltage, which will rise when the system has a ground fault. Through such a connection mode, the control device can monitor the change of the zero sequence voltage in real time, detect the ground fault in time and take corresponding protection measures.

[0065] Referring to Figure 2 A kind of telemetry loop further includes CT terminal box 400.

[0066] The CT terminal box 400 is connected to the input terminals of the Ia, Ib and Ic current transformers 205, 206 and 207 in the line monitoring and control device 200 through the Ia, Ib and Ic lines 401, 402 and 403 respectively. The output terminals of the Ia, Ib and Ic current transformers 205, 206 and 207 are connected to the Ian, Ibn and Icn lines 404, 405 and 406 respectively. The Ian line 404 is connected to the Ibn line 405, and the Ibn line 405 is connected to the Icn line 406. The Ian, Ibn or Icn line is connected to the CT terminal box 400.

[0067] Next, how the line monitoring and control device 200 monitors the current in the circuit is explained.

[0068] The current transformer is installed in the main circuit with a large current. Its primary side is connected in series in the measured circuit. When there is current flowing in the main circuit, the primary side of the current transformer will generate a current proportional to it. The secondary side of the current transformer converts the large current of the primary side into a small current, which is suitable for the measurement of the monitoring and control device. The output of the secondary side is connected to the CT terminal box 400 through the cable. The CT terminal box 400 is the centralized connection point of the output of the secondary side of the current transformer, which is connected to the input terminals of the Ia, Ib and Ic current transformers 205, 206 and 207 in the line monitoring and control device 200 through the Ia, Ib and Ic lines 401, 402 and 403 respectively.

[0069] The cable extends from the CT terminal box 400 to the monitoring and control device, transmitting the current signal to the input terminals of the monitoring and control device. In the monitoring and control device, these current signals are input to the corresponding Ia, Ib and Ic current transformers 205, 206 and 207 through the Ia, Ib and Ic lines 401, 402 and 403 respectively. The Ia, Ib and Ic current transformers 205, 206 and 207 in the line monitoring and control device 200 further process these current signals, converting them into signals suitable for measurement by the monitoring and control device. The processed signals can be received by the monitoring and control device and used to measure and display the current value. The monitoring and control device amplifies and filters the collected current signals to improve the quality and accuracy of the signals. The processed analog current signals are converted into digital signals for subsequent digital signal processing and calculation. Various electrical parameters such as the effective value of the current and power are calculated based on the converted digital signals.

[0070] The line monitoring and control device 200 is provided with an Io current transformer 208. The input terminal of the Io current transformer 208 is connected to the CT terminal box 400 through the Io line 407, and the output terminal of the Io current transformer 208 is connected to the CT terminal box 400 through the Ion line 408.

[0071] The non-same name terminals of the secondary sides of the three current transformers in the CT terminal box 400 are connected together to form the output end of the open delta winding. Then, the input end of the Io transformer 208 is connected to this output end. The output end of the Io transformer 208 is connected back to the connection point of the same name terminals of the secondary sides of the three current transformers in the CT terminal box 400, i.e. the neutral point, through the Ion line 408. In this way, the zero sequence current signal can form a complete loop, ensuring that the Io transformer 208 can accurately detect the zero sequence current and transmit it to the control device for further processing and analysis.

[0072] In a three-phase system, the zero sequence current is the vector sum of the three-phase currents. In normal operation, the vector sum of the three-phase currents is zero, so the zero sequence current should also be zero. When a ground fault occurs, the zero sequence current will increase significantly. The Io transformer 208 is used to detect this zero sequence current, which will increase when a ground fault occurs in the system. Through the connection of the open delta winding and the Io transformer 208, the control device can monitor the changes in the zero sequence current in real time and detect ground faults in a timely manner.

[0073] Reference Figure 3 A control device, the control device comprising a cabinet 200A, the front layout of the cabinet 200A is as shown in FIG. 2A, and the back layout of the cabinet 200A is as shown in FIG. 2B. Figure 3 Figure 3

[0074] Among them, the line control 200 is arranged in the cabinet 200A, and the line control 200 comprises a Ua transformer 201, a Ub transformer 202, a Uc transformer 203, a Uo transformer 204, an Ia transformer 205, an Ib transformer 206, an Ic transformer 207, and an Io transformer 208. The line control 200 is connected to the PT terminal box 100 and the CT terminal box 400.

[0075] The line control 200 can be arranged in multiple, and each line control 200 has multiple current transformers and voltage transformers. Through the connection ports of the line control 200, i.e. the input ports and output ports of the voltage transformers and current transformers in the line control 200, the line control 200 is connected to the line to be monitored, so as to monitor the voltage and current of the line.

[0076] Reference Figure 4 A control device telemetry method, comprising the following steps:

[0077] S1: The line control 200 receives the phase voltage signals and zero sequence voltage signals transmitted by the PT terminal box 100, and the phase current signals and zero sequence current signals transmitted by the CT terminal box 400.

[0078] ​​S2: Calculate line voltage, phase voltage, current effective value, and power, power factor and frequency according to the collected voltage and current signals.

[0079] S3: Real-time monitor the operation state of power system, judge whether overload, short circuit or ground fault occurs.

[0080] In steps S1-S3, signal collection, signal processing, signal conversion, parameter calculation, system monitoring and protection action are included.

[0081] Signal collection: The line measurement and control 200 receives the phase voltage signals from the PT terminal box 100 through the Ua line 101, Ub line 102, Uc line 103, and receives the zero sequence voltage signal through the Uo line 105. The line measurement and control 200 receives the phase current signals from the CT terminal box 400 through the Ia line 401, Ib line 402, Ic line 403, and receives the zero sequence current signal through the Io line 407.

[0082] Among them, the Ua transformer 201, Ub transformer 202, Uc transformer 203, Uo transformer 204 in the measurement and control device respectively receive the phase voltage signals from the PT terminal box 100 through the Ua line 101, Ub line 102, Uc line 103, Uo line 105, the loop formed by the Ua line 101 and the Un line 104 makes the Ua transformer 201 receive the A-phase voltage signal, the loop formed by the Ub line 102 and the Un line 104 makes the Ub transformer 202 receive the B-phase voltage signal, the loop formed by the Uc line 103 and the Un line 104 makes the Uc transformer 203 receive the C-phase voltage signal, and the loop formed by the Uo line 105 and the Uon line 106 makes the Uo transformer 204 receive the zero sequence voltage signal.

[0083] Among them, the Ia transformer 205, Ib transformer 206, Ic transformer 207, Io transformer 208 in the measurement and control device respectively receive the phase current signals from the CT terminal box 400 through the Ia line 401, Ib line 402, Ic line 403, Io line 407, the loop formed by the Ia line 401 and the Ian line 404 makes the Ia transformer 205 receive the A-phase current signal, the loop formed by the Ib line 402 and the Ibn line 405 makes the Ib transformer 206 receive the B-phase current signal, the loop formed by the Ic line 403 and the Icn line 406 makes the Ic transformer 207 receive the C-phase current signal, and the loop formed by the Io line 407 and the Ion line 408 makes the Io transformer 208 receive the zero sequence current signal.

[0084] Signal processing: The line measurement and control 200 preliminarily processes the collected phase voltage signals and zero sequence voltage signals, and preliminarily processes the collected phase current signals and zero sequence current signals, including signal amplification and filtering, to improve the quality and accuracy of the signals.

[0085] Signal conversion: The line monitoring and control device 200 converts the processed phase voltage signals, zero-sequence voltage signals, phase current signals, and zero-sequence current signals into digital signals. The continuous analog signals are converted into discrete digital signals through the built-in analog-to-digital conversion module, so as to facilitate subsequent digital signal processing and calculation.

[0086] Parameter calculation: The line voltage, phase voltage, effective value of current, power, power factor, and frequency are calculated based on the converted digital signals.

[0087] The line voltage can be calculated by the difference between the two-phase phase voltages. The effective value of the current can be calculated by the root mean square of the current signal. The power can be calculated by the integral of the product of the voltage and current signals. The power factor can be calculated by the phase difference between the voltage and current. The frequency can be calculated by the period measurement of the voltage or current signal.

[0088] System monitoring: The line monitoring and control device 200 monitors the operating state of the power system in real time through the PT terminal box 100 and the CT terminal box 400. When the monitored voltage or current exceeds the preset threshold, it is determined that the system may have an overload or short-circuit fault. When the monitored zero-sequence voltage or zero-sequence current exceeds the preset threshold, it is determined that the system may have a ground fault.

[0089] Protection action: When a system fault is detected, the monitoring and control device sends an alarm signal and takes appropriate protective measures according to the preset protection logic.

[0090] Finally, it should be pointed out that the above detailed description of the methods and devices is only an embodiment, and those skilled in the art can modify the embodiment in different ways without departing from the scope of the present application.

Claims

1. A telemetry loop, characterized by: Comprising, The PT terminal box (100) is connected with the input end of the Ua mutual inductor (201), the Ub mutual inductor (202) and the Uc mutual inductor (203) in the line monitoring and control (200) through the Ua line (101), the Ub line (102) and the Uc line (103) respectively. The output end of the Ua mutual inductor (201), the Ub mutual inductor (202) and the Uc mutual inductor (203) are connected with the PT terminal box (100) through the Un line (104). The opening and closing of the Ua line (101), the Ub line (102) and the Uc line (103) are controlled by the rotary switch (300).

2. The telemetry loop of claim 1, wherein: The rotary switch (300) comprises contact one (301), contact two (302), contact three (303), contact four (304), contact five (305) and contact six (306). The contact one (301) and the contact two (302) are connected on the Ua line (101), the contact three (303) and the contact four (304) are connected on the Ub line (102), and the contact five (305) and the contact six (306) are connected on the Uc line (103).

3. The telemetry loop of claim 2, wherein: The line monitoring and control (200) is provided with the Uo mutual inductor (204), the input end of the Uo mutual inductor (204) is connected with the PT terminal box (100) through the Uo line (105), and the output end of the Uo mutual inductor (204) is connected with the Uon line (106), and the Uon line (106) is connected with the Un line (104).

4. The telemetry loop of claim 3, wherein: The CT terminal box (400) is connected with the input end of the Ia mutual inductor (205), the Ib mutual inductor (206) and the Ic mutual inductor (207) in the line monitoring and control (200) through the Ia line (401), the Ib line (402) and the Ic line (403) respectively, the output end of the Ia mutual inductor (205), the Ib mutual inductor (206) and the Ic mutual inductor (207) is connected with the Ian line (404), the Ibn line (405) and the Icn line (406) respectively, the Ian line (404) is connected with the Ibn line (405), the Ibn line (405) is connected with the Icn line (406), and the Ian line (404), the Ibn line (405) or the Icn line (406) is connected with the CT terminal box (400).

5. The telemetry loop of claim 4, wherein: The line monitoring and control (200) is provided with the Io mutual inductor (208), the input end of the Io mutual inductor (208) is connected with the CT terminal box (400) through the Io line (407), and the output end of the Io mutual inductor (208) is connected with the CT terminal box (400) through the Ion line (408).

6. A measurement and control device, characterized by: The telemetry loop as claimed in any one of claims 1-5, wherein the measurement and control device comprises a cabinet (200A), and the line measurement and control (200) is arranged in the cabinet (200A), and the line measurement and control (200) comprises a Ua mutual inductor (201), a Ub mutual inductor (202), a Uc mutual inductor (203), a Uo mutual inductor (204), an Ia mutual inductor (205), an Ib mutual inductor (206), an Ic mutual inductor (207), and an Io mutual inductor (208), and the line measurement and control (200) is connected to the PT terminal box (100) and the CT terminal box (400) respectively.

7. A telemetry method for the TT&C device of claim 6, characterized in that: The method comprises the following steps: S1: The line measurement and control (200) receives the phase voltage signals and the zero sequence voltage signal transmitted by the PT terminal box (100), and receives the phase current signals and the zero sequence current signal transmitted by the CT terminal box (400); S2: The line voltage, the phase voltage, the current effective value, and the power, the power factor, and the frequency are calculated according to the collected voltage and current signals; S3: The operation state of the power system is monitored in real time, and it is determined whether an overload, a short circuit, or a ground fault occurs.

8. The telemetry method of claim 7, wherein: In step S1, the line measurement and control (200) receives the phase voltage signals from the PT terminal box (100) through the Ua line (101), the Ub line (102), and the Uc line (103), and receives the zero sequence voltage signal through the Uo line (105), and the line measurement and control (200) receives the phase current signals from the CT terminal box (400) through the Ia line (401), the Ib line (402), and the Ic line (403), and receives the zero sequence current signal through the Io line (407).

9. The telemetry method of claim 8, wherein: In step S2, the line measurement and control (200) performs preliminary processing on the collected phase voltage signals and zero sequence voltage signal, and performs preliminary processing on the collected phase current signals and zero sequence current signal; The line measurement and control (200) converts the processed phase voltage signals, zero sequence voltage signal, phase current signals, and zero sequence current signal into digital signals; The line voltage, the phase voltage, the current effective value, and the power, the power factor, and the frequency are calculated according to the converted digital signals.

10. The telemetry method of claim 9, wherein: In step S3, the line measurement and control (200) monitors the operation state of the power system in real time through the PT terminal box (100) and the CT terminal box (400), and when the monitored voltage or current exceeds a preset threshold value, it is determined that the system may have an overload or short circuit fault, and when the monitored zero sequence voltage or zero sequence current exceeds a preset threshold value, it is determined that the system may have a ground fault; When a system fault is detected, the measurement and control device sends an alarm signal, and takes corresponding protection measures according to a preset protection logic.

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