Substation Secondary System Series Power Test Device and Method

Abstract

The present invention discloses a series power test device and method for a substation secondary system, relating to the technical field of secondary systems in power plants or substations; the device includes a processor unit, a power supply unit, a DC voltage acquisition unit, a switch button, a display unit, signal acquisition test leads, a grounding test lead, and a confirmation button. The power supply unit is electrically connected to the switch button, the processor unit, and the display unit respectively. The DC voltage acquisition unit is electrically connected to each test lead, the processor unit, and the confirmation button respectively; the method is based on the above device and adopts the power cut-off method in cooperation with the test potential method. When a power supply is cut off, if there is no power at the common terminal of the power supply, it is known that there is no series power defect. If there is power at the common terminal of the power supply, it is known that there is a series power defect; through the processor unit, the power supply unit, the DC voltage acquisition unit, the switch button, the display unit, the signal acquisition test leads, the grounding test lead, the confirmation button, etc., it realizes detecting and knowing the series power between DC power systems.

Description

Technical Field

[0001] The present invention relates to the technical field of secondary systems in power plants or substations, and particularly to a series power test device and method for a substation secondary system. Background Art

[0002] Faults in DC systems can be classified into DC grounding, AC intrusion into DC, and mutual series connection between several DCs.

[0003] This application mainly studies the series power problem between several DCs.

[0004] The search formula is TACD_ALL: (substation AND secondary AND system AND series power) AND ALL_AN: (electric power), and the relatively close prior art solutions are as follows.

[0005] The authorized announcement number is CN 103323655 B, and the name is a non-contact AC-DC series power on-line detection device and its on-line detection method. The application publication number is CN 105988046 A, and the name is a detection method and system for judging the intrusion of AC signals into a DC system. Both are for the detection of AC intrusion into DC, which is different from the technical problem to be solved by this application.

[0006] The authorized announcement number is CN 101216543 B, and the name is a DC system grounding fault detection and verification method and its special device, which is a detection method for finding DC grounding, and is different from the technical problem to be solved by this application.

[0007] The authorized announcement number is CN 105116352 B, and the name is a series power detection method for a substation dual DC power supply system, which is a method for detecting mutual series connection between several DCs. The method adopted is to inject a small current into the series power combination. Since the injected current will mainly flow into the series power branch, the voltage, current, and impedance values of each branch are measured, and the combination with the smallest impedance value is the series power branch. This document injects current into the substation secondary system, which brings certain risks to the stable operation of the secondary system. In addition, the series power branch is determined through theoretical calculation. The DC system is a common system, and once there is a risk, it will affect many secondary devices. This invention patent does not add AC to the operating DC system, but only collects the potentials of some key points, reducing the risk. Its technical solution is different from that of this application, and the inventive concept is different.

[0008] The method mentioned in this patent is mainly used for the acceptance work before the commissioning of new equipment. During the acceptance process of new equipment, the situation of electrical connection errors in the secondary wiring leading to electrical leakage is very common. This patent can expose all the electrical leakage situations by collecting the potentials at several key points and setting the variable positions of key nodes in each loop, and cooperating with the loop isolation test. The method proposed in this patent focuses more on direct measurement, without injecting current into the secondary system, only detecting the potentials at several key points in the secondary system, which is very intuitive and will not affect the operation of the secondary system. In addition, the device mentioned in this patent can simultaneously detect the situation of each power supply in real time, avoiding the embarrassment that staff hold multimeters one by one to find the key potential points in the conventional method, and also avoiding misoperation.

[0009] Existing technical problems and considerations:

[0010] How to solve the technical problem of detecting electrical leakage between DC power supply systems. Summary of the Invention

[0011] The technical problem to be solved by the present invention is to provide a device and method for testing electrical leakage in a substation secondary system, so as to solve the technical problem of detecting electrical leakage between DC power supply systems.

[0012] To solve the above technical problem, the technical solution adopted by the present invention is: A device for testing electrical leakage in a substation secondary system includes a housing, a processor unit, a power supply unit, and a DC voltage acquisition unit arranged in the housing, and a switch button, a display unit, signal acquisition test leads, a grounding test lead, and a confirmation button arranged on the housing. The switch button is electrically connected to the power supply unit, the power supply unit is electrically connected to the processor unit, the power supply unit is electrically connected to the display unit, the signal acquisition test leads are electrically connected to the DC voltage acquisition unit, the DC voltage acquisition unit is electrically connected to the processor unit, the DC voltage acquisition unit is electrically connected to the grounding test lead, and the confirmation button is electrically connected to the processor unit.

[0013] A further technical solution lies in that: the signal acquisition test leads include the first to sixth test leads with the same structure, the DC voltage acquisition units include the first to sixth DC voltage acquisition units with the same structure, the confirmation buttons include the first to sixth confirmation buttons with the same structure. One end of the first test lead passes through the housing and is electrically connected to the first DC voltage acquisition unit; one end of the second test lead passes through the housing and is electrically connected to the second DC voltage acquisition unit; one end of the third test lead passes through the housing and is electrically connected to the third DC voltage acquisition unit; one end of the fourth test lead passes through the housing and is electrically connected to the fourth DC voltage acquisition unit; one end of the fifth test lead passes through the housing and is electrically connected to the fifth DC voltage acquisition unit; one end of the sixth test lead passes through the housing and is electrically connected to the sixth DC voltage acquisition unit; one end of the grounding test lead passes through the housing and is electrically connected to each DC voltage acquisition unit; the first confirmation button is electrically connected to the processor unit; the second confirmation button is electrically connected to the processor unit; the third confirmation button is electrically connected to the processor unit; the fourth confirmation button is electrically connected to the processor unit; the fifth confirmation button is electrically connected to the processor unit; the sixth confirmation button is electrically connected to the processor unit.

[0014] A further technical solution lies in that: it further includes a charging interface arranged on the housing, and the charging interface is electrically connected to the power supply unit.

[0015] A further technical solution lies in that: the display unit is a liquid crystal display.

[0016] A further technical solution lies in that: the display unit is an LED display.

[0017] A method for testing series power connection in the secondary system of a substation, based on the above device, adopts the power-off method in cooperation with the test potential method. When one power supply is cut off, if there is no electricity at the common terminal of this power supply, it is known that there is no series power connection defect; if there is electricity at the common terminal of this power supply, it is known that there is a series power connection defect.

[0018] A further technical solution lies in that: specifically, it includes the following steps. Before the test is carried out, the grounding test lead is grounded, each test lead is connected to the corresponding power supply common terminal, and the potential magnitude is monitored in real time.

[0019] A further technical solution lies in that: it further includes the following steps. For the situation where normally open contacts and normally closed contacts are respectively taken for two DC power supplies, before the series power connection test at intervals, the authenticity of the signal sent by the monitoring machine is judged, and whether there are abnormal signs in the DC system is judged.

[0020] A further technical solution lies in that: it further includes the following steps. For the situation where normally open contacts or normally closed contacts are taken for both power supplies or the telemetry power supplies are used crosswise, the contacts of the components are counted, and the test work is carried out one by one to make the nodes of the relay closed, and then the series power connection combinations are found one by one through the power-off method in cooperation with the potential test method.

[0021] A further technical solution lies in the following steps: for the cases of wrong wiring of adjacent terminals and the DC positive and negative poles of two circuits coming from different device power supplies, the loop disconnection method is adopted and combined with potential testing to find out whether there is a defect of electrical connection in series in the loop.

[0022] The beneficial effects produced by adopting the above technical solution are as follows:

[0023] A series electrical connection testing device for a substation secondary system includes a housing, a processor unit, a power supply unit, and a DC voltage acquisition unit arranged in the housing, as well as a switch button, a display unit, a signal acquisition test lead, a grounding test lead, and a confirmation button arranged on the housing. The switch button is electrically connected to the power supply unit, the power supply unit is electrically connected to the processor unit, the power supply unit is electrically connected to the display unit, the signal acquisition test lead is electrically connected to the DC voltage acquisition unit, the DC voltage acquisition unit is electrically connected to the processor unit, the DC voltage acquisition unit is electrically connected to the grounding test lead, and the confirmation button is electrically connected to the processor unit. With this technical solution, it can detect and know the electrical connection in series between DC power systems through the processor unit, the power supply unit, the DC voltage acquisition unit, the switch button, the display unit, the signal acquisition test lead, the grounding test lead, the confirmation button, etc.

[0024] A series electrical connection testing method for a substation secondary system, based on the above device, adopts the loop disconnection method in combination with the potential testing method. When one power supply is disconnected, if there is no electricity at the common terminal of this power supply, it is known that there is no defect of electrical connection in series. If there is electricity at the common terminal of this power supply, it is known that there is a defect of electrical connection in series. With this technical solution, it can detect and know the electrical connection in series between DC power systems through the above device and the loop disconnection method in combination with the potential testing method, etc.

[0025] See the description in the specific implementation part for details. Description of the Drawings

[0026] Figure 1 is the principle block diagram of Embodiment 1 of the present invention;

[0027] Figure 2 is the device distribution diagram of Embodiment 1 of the present invention;

[0028] Figure 3 is the on-site wiring diagram of Embodiment 1 of the present invention;

[0029] Figure 4 is the flow chart of Embodiment 2 of the present invention;

[0030] Figure 5a is the circuit diagram of the closing loop in the breaker control loop;

[0031] Figure 5b is the circuit diagram of the first group of tripping loops in the breaker control loop;

[0032] Figure 5c It is the circuit diagram of the second set of trip circuits in the breaker control circuit;

[0033] Figure 6 It is the circuit diagram of the telemetry signal and recording wave circuits of the non-full phase relay;

[0034] Figure 7a It is the circuit diagram of the telemetry signal circuit of the oil pressure state;

[0035] Figure 7b It is the circuit diagram of the telemetry signal circuit of the gas pressure state;

[0036] Figure 8 It is the circuit diagram of the secondary circuit with correct wiring of CK1;

[0037] Figure 9 It is the circuit diagram of the cross-connection of the negative poles of two sets of contacts of CK1;

[0038] Figure 10 It is the circuit diagram of the cross-connection of the positive poles on two sets of contacts of CK1;

[0039] Figure 11 It is the circuit diagram of the correct wiring of the 47TX1 relay;

[0040] Figure 12 It is the circuit diagram of the cross-connection of the negative poles of two sets of contacts of the 47TX1 relay;

[0041] Figure 13 It is the circuit diagram of the cross-connection of the positive poles of two sets of contacts of the 47TX1 relay;

[0042] Figure 14 It is the circuit diagram of the adjacent terminal block schematic diagram;

[0043] Figure 15 It is the circuit diagram of the telemetry signal circuit with correct wiring;

[0044] Figure 16 It is the circuit diagram of the series connection of two telemetry signal power supplies. Specific implementation manners

[0045] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way constitutes a limitation on the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present application.

[0046] In the following description, numerous specific details are set forth to provide a thorough understanding of the present application. However, the present application may also be implemented in other ways different from those described herein. Persons skilled in the art can make similar generalizations without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0047] Embodiment 1:

[0048] As Figure 1 and Figure 2 shown, the present invention discloses a series power test device for a secondary system of a substation, which includes a housing, a processor unit fixed in the housing, a power supply unit, a DC voltage acquisition unit, and a switch button, a charging interface, a display unit, a signal acquisition test lead, a grounding test lead, and a confirmation button fixed on the housing. The switch button is electrically connected to the power supply unit, the charging interface is electrically connected to the power supply unit, the power supply unit is electrically connected to the processor unit, the power supply unit is electrically connected to the display unit, the signal acquisition test lead is electrically connected to the DC voltage acquisition unit, the DC voltage acquisition unit is electrically connected to the processor unit, the DC voltage acquisition unit is electrically connected to the grounding test lead, and the confirmation button is electrically connected to the processor unit.

[0049] As Figure 2 shown, the signal acquisition test lead includes first to sixth test leads with the same structure, the DC voltage acquisition unit includes first to sixth DC voltage acquisition units with the same structure, the confirmation button includes first to sixth confirmation buttons with the same structure. One end of the first test lead passes through the housing and is electrically connected to the first DC voltage acquisition unit, one end of the second test lead passes through the housing and is electrically connected to the second DC voltage acquisition unit, one end of the third test lead passes through the housing and is electrically connected to the third DC voltage acquisition unit, one end of the fourth test lead passes through the housing and is electrically connected to the fourth DC voltage acquisition unit, one end of the fifth test lead passes through the housing and is electrically connected to the fifth DC voltage acquisition unit, one end of the sixth test lead passes through the housing and is electrically connected to the sixth DC voltage acquisition unit, one end of the grounding test lead passes through the housing and is electrically connected to each DC voltage acquisition unit, the first confirmation button is electrically connected to the processor unit, the second confirmation button is electrically connected to the processor unit, the third confirmation button is electrically connected to the processor unit, the fourth confirmation button is electrically connected to the processor unit, the fifth confirmation button is electrically connected to the processor unit, and the sixth confirmation button is electrically connected to the processor unit.

[0050] The display unit is a liquid crystal display.

[0051] Among them, the processor unit, the power supply unit, the DC voltage acquisition unit, the switch button, the charging interface, the display unit, the signal acquisition test lead, the grounding test lead, and the confirmation button itself, as well as the corresponding communication connection technologies, are prior arts and will not be elaborated herein.

[0052] Instructions for Use of Embodiment 1:

[0053] As Figure 2 and Figure 3 shown, the first test lead is connected to the positive pole of the first control power supply I, the second test lead is connected to the negative pole of the first control power supply I, the third test lead is connected to the positive pole of the second control power supply II, the fourth test lead is connected to the negative pole of the second control power supply II, the fifth test lead is connected to the positive pole of the telecontrol signal power supply, and the sixth test lead is connected to the positive pole of the oscillographic recording power supply.

[0054] As Figure 2 and Figure 3 shown, the first confirmation button is used when detecting the positive pole of the first control power supply I, the second confirmation button is used when detecting the negative pole of the first control power supply I, the third confirmation button is used when detecting the positive pole of the second control power supply II, the fourth confirmation button is used when detecting the negative pole of the second control power supply II, the fifth confirmation button is used when detecting the positive pole of the telecontrol signal power supply, and the sixth confirmation button is used when detecting the positive pole of the oscillographic recording power supply.

[0055] Embodiment 2:

[0056] As Figure 4 shown, the present invention discloses a method for testing series power connection in a substation secondary system. Based on the device of Embodiment 1, the power-off method is used in combination with the test potential method. When a power supply is disconnected, if there is no power at the common terminal of the power supply, it is known that there is no series power connection defect; if there is power at the common terminal of the power supply, it is known that there is a series power connection defect. The specific steps are as follows:

[0057] Before the test is carried out, the grounding test lead is grounded, and the potential magnitude is monitored in real time.

[0058] For the case where normally open contacts and normally closed contacts are respectively taken for two DC power supplies, before the series power connection test in this interval, the authenticity of the signal sent to the monitoring machine is judged, and whether there are abnormal signs in the DC system is judged.

[0059] For the case where normally open contacts or normally closed contacts are taken for both power supplies or the telecontrol signal power supply is used crosswise, the contacts of the components are counted, and the test work is carried out one by one to close the nodes of the relay, and then the series power connection combinations are found one by one through the power-off method in combination with the potential test method.

[0060] For the case where adjacent terminals are wrongly wired and the positive and negative poles of two DC power supplies come from different device power supplies, the power-off method is used in combination with the potential test to find out whether there is a series power connection defect in the circuit.

[0061] Embodiment 3:

[0062] Embodiment 3 is different from Embodiment 1 in that the display unit is an LED display. Other identical parts will not be described herein again.

[0063] Use of the present application:

[0064] A method for detecting whether there is a phenomenon of series power connection in a secondary system is proposed. A specific operation process is proposed in combination with the method, and a corresponding device is developed. The device is connected to the key points of the secondary system, and the potential of each key point is detected to be normal. In combination with the specific operation process, it is judged whether there is a phenomenon of series power connection.

[0065] Technical problems to be solved by the present application:

[0066] The DC power supply system of a substation serves as the power supply for protection devices and circuit breaker operating power supplies, etc. It is one of the most important systems in the substation. Its operating condition has a crucial effect on the action behavior of relay protection devices and circuit breakers. Therefore, it is required that the DC system and its network must have a high degree of reliability. The DC system is like the nervous system of a person, covering a very wide range. Any occurrence of AC-DC series connection, series connection between DCs, or grounding or abnormality at any place can affect the entire DC system.

[0067] The substation adopts two sets of independently operating DC power supply systems, which can improve the reliability of the station power supply system. When the DC buses of the double-set DC power supply system in the substation are normal, the bus sectional operation mode is adopted. When the system needs it, the tie switch between the two DC buses can be closed to become the parallel operation mode, that is, the positive and negative poles of the I-section bus are respectively connected to the positive and negative poles of the II-section bus in correspondence. However, in actual operation, some improper factors will cause the two buses to be series-connected to each other. The DC series connection will cause changes in the positive and negative pole-to-earth voltages and their insulation conditions of the two DC buses in the substation. If a grounding fault occurs in the DC power supply system at this time, it will bring safety problems to the DC power supply system.

[0068] If the two sets of DCs are series-connected, any grounding of one set of DCs will cause both sets of DCs to be pulled to one side, resulting in the normal operation of the two sets of protections being affected. If two devices use the same set of DCs, the series connection between the two sets of devices, although it will not cause the phenomenon that both sets of DCs are pulled to one side, may cause DC grounding or electric shock to personnel during operation.

[0069] Description of the technical solution:

[0070] The secondary circuit is like the nervous system of a substation, covering a very wide range and having a very complex wiring. How to detect all series power connection defects by scientific methods during the infrastructure acceptance and equipment inspection work is particularly important. Based on on-site experience and actual cases, this article summarizes four typical types of series power connection and studies the detection methods and operation processes for each type.

[0071] 1. Research on the Type of Electrical Connection in Series and Testing Method

[0072] Since there are many contacts involved in the breaker control loop, including breaker position contacts, non - full - phase relay contacts, low - oil - pressure closing and tripping locking contacts, and low - gas - pressure closing and tripping locking contacts, etc., for comprehensiveness, this paper takes the U - phase control loop as an example to study the electrical connection in series of each contact under incorrect wiring conditions.

[0073] As Figure 5a shown, it is the closing loop. Figure 5b shown, it is the first group of tripping loops. Figure 5c shown, it is the second group of tripping loops, see the control loop. For clarity, only the key contacts are drawn in the figure. Among them, 47TX1 (47TX2) is the non - full - phase relay of the first group (second group). When the normal three - phase breaker is in the off - position or on - position, 47TX1 is in the non - excited state, and the normally open contact of 47TX1 is open; DL is the auxiliary position contact of the breaker. In the figure, both the normally open and normally closed contacts are the states when the breaker is in the off - position; Y1, Y2, and Y3 are the closing coil, the first - group tripping coil, and the second - group tripping coil respectively; CK1 is the contact reflecting the energy - storage pressure state. The normally open contact is in the state when the hydraulic disc spring or spring is without pressure. Since it is in a pressurized state during normal operation, the normally open contact of CK1 is closed during normal operation; 2ZJ (3ZJ) is the relay reflecting the SF6 gas - pressure state. The normally closed contact is the state when the relay is non - excited. During normal operation, SF6 is in a pressurized state, and the 2ZJ relay is non - excited. Therefore, the normally closed contact of the 2ZJ relay is closed.

[0074] As Figure 6 shown, it is the non - full - phase telemetry loop and the recording loop, and each power supply takes different normally open contacts of the non - full - phase relay.

[0075] As Figure 7a 、 Figure 7b shown, they are the telemetry loops of the oil - pressure state and the gas - pressure state respectively.

[0076] As Figure 5a 、 Figure 5b 、 Figures 5c to 7a 、 Figure 7b shown, on the 47TX1 relay contact, the first - group control power supply, the telemetry power supply, and the recording power supply are connected; on the CK1 contact, two groups of control power supplies and the telemetry power supply are connected; on the 2ZJ (3ZJ) contact, the first - group (second - group) control power supply and the telemetry power supply are connected. During construction, incorrect connection of the above secondary wiring will lead to electrical connection in series.

[0077] According to the characteristics of taking contacts from each DC circuit on a specific component, it can be divided into:

[0078] (1) Two DC circuits take normally open and normally closed contacts respectively.

[0079] (2) Both DC circuits use normally open or normally closed contacts.

[0080] In addition, based on experience, two types can be added:

[0081] (3) At adjacent terminal blocks or adjacent interfaces of relays, two DC lines are connected in parallel.

[0082] (4) The positive and negative poles of the telesignaling circuit come from different measurement and control devices.

[0083] Therefore, this application focuses on the following four situations. It should be noted that the secondary line is complicated and involves a wide range of situations. The situations that lead to cross-current include but are not limited to the four situations mentioned in this article.

[0084] 1.1 Two DC circuits take normally open and normally closed contacts respectively

[0085] from Figure 5a , Figure 5b , Figure 5c , Figure 6 and Figure 7a , Figure 7b It can be seen that on CK1 and 2ZJ, the control power supply and remote signal power supply take their normally open contacts and normally closed contacts respectively. Take CK1 as an example for research.

[0086] It should be noted that, considering the workload, it is impossible to measure at multiple locations in the circuit when testing the potential. A more realistic approach is to measure the potential at the common end, that is, to measure the potential of 101, 102, J701, and S701. However, when a certain contact is actuated, although it has caused a series of currents in two DC lines, due to the isolation effect of other contacts in the entire circuit, it is not necessarily possible to find abnormalities by testing the potential at the common end of the power supply. This requires ensuring that when a series of currents occur at a certain contact, the other contacts in the circuit are conductive, thereby ensuring that the common end can represent the potential of the entire circuit. For this reason, when analyzing the series of currents at a specific contact, it should be ensured that the other contacts in the circuit are in a conductive state. In addition, in order to form a control test, when analyzing a specific contact, only this one variable is maintained, and the states of other contacts in the circuit should remain unchanged and conductive. The following is referred to as the unique variable principle.

[0087] According to the above theory, when analyzing the CK1 contact, keep Figure 5a , Figure 5b , Figure 5c The DL and 2ZJ contacts are closed and no position change occurs.

[0088] like Figure 8 For simplicity, the CK1 contact is shown in Figure 5a , Figure 5b , Figure 5c and Figure 7a , Figure 7bstudied together, and finally formed Figure 8 the model shown.

[0089] As Figure 9 shown, for the two sets of contacts of CK1, the negative poles are cross-connected. Under normal conditions, since the normally open contact of CK1 is actually in the closed state, the negative end J903 of the telemetry signal is positively charged, and the blocking signal can be uploaded to the monitoring machine. The actual pressure has not reached the blocking level, which does not correspond to the primary equipment, and it is extremely obvious to guide the operators to eliminate the defects. Even if it is not discovered in time, when doing the blocking test and releasing the pressure until the CK1 contact operates, the normally closed contact of CK1 closes, and the positive pole J701 of the telemetry common end and the negative pole 102 of the control common end are short-circuited, and the phenomenon is also very obvious.

[0090] As Figure 10 shown, for the two sets of contacts of CK1, the positive poles are cross-connected. Under normal conditions, a short circuit between the positive pole of the telemetry signal and the negative pole of the control can occur.

[0091] In short, the series power phenomenon caused by such incorrect wiring is very intuitive and obvious, and can be discovered and eliminated in time at the initial stage of equipment acceptance.

[0092] 1.2 Both DC circuits take normally open or normally closed contacts

[0093] From Figure 5a , Figure 5b , Figure 5c , Figure 6 and Figure 7a , Figure 7b it can be seen that on the 47TX1 relay, the control power supply, the telemetry signal power supply, and the recording power supply respectively take their normally open contacts. In fact, Figure 5a , Figure 5b , Figure 5c the two sets of control power supplies in also respectively take the normally open contacts of CK1, which are of the same type. In this paper, the non-full-sequence relay 47TX1 is taken as an example for research. The control power supply, the telemetry signal power supply, and the recording power supply all need to take the contacts of 47TX1, and there are many combinations of series power. For the convenience of analysis, the Figure 5a , Figure 5b , Figure 5c and Figure 6 involving the contacts of 47TX1 are studied together, as shown in Figure 11 shown.

[0094] As Figure 12 shown, in the specific analysis, this section only takes the series power of the control power supply and the telemetry signal power supply as an example. In fact, there is a possibility of series power between the control power supply and the recording power supply, and between the telemetry signal power supply and the recording power supply.

[0095] As Figure 12 and Figure 13As shown, when the circuit breaker is in the full-phase state of three-phase closing or opening, the normally open contact of 47TX1 is in the open state. Therefore, even in the Figure 12 and Figure 13 shown incorrect wiring, since the normally open contact of 47TX1 is open, there will be no electrical cross-talk. Only when the normally open contact of 47TX1 closes, will there be an electrical cross-talk phenomenon.

[0096] Obviously, a non-full-phase state needs to be created. Following the "unique variable" principle mentioned above, it is necessary to ensure that the position of the U-phase circuit breaker remains unchanged and the DL contact remains closed. Therefore, by adjusting the position of the V or W-phase circuit breaker, the circuit breaker is in the non-full-phase state.

[0097] As Figure 12 shown, after the contact of 47TX1 closes, although there is an electrical cross-talk phenomenon, J901 is positively charged, the non-full-phase signal can be sent out normally, and there will be no abnormality on the monitoring machine. It is necessary to further analyze by using the power-off method in cooperation with testing the potential of each power supply circuit.

[0098] As Figure 12 shown, in the incorrect wiring shown in Figure 12 , when the control power supply is pulled out, the telemetry signal power supply and the recording wave power supply remain normal. At this time, the negative pole J901 of the telemetry signal power supply will be connected to the positive pole common terminal 101 of the control power supply through the control circuit, resulting in 101 being negatively charged. And the positive pole J701 of the telemetry signal power supply will be connected to the negative pole common terminal 102 of the control power supply through the telemetry signal circuit, resulting in 102 being positively charged. Similarly, in the incorrect wiring shown in Figure 13 , it will cause the same phenomenon as in Figure 12 .

[0099] If the control power supply and the recording wave power supply are connected wrongly or the telemetry signal power supply and the recording wave power supply are connected wrongly, the electrical cross-talk phenomenon described above can be found by using the power-off method in cooperation with measuring the potential.

[0100] 1.3 In the case of incorrect wiring of adjacent terminals

[0101] In the design, two power supplies are connected to adjacent terminals of the relay or adjacent terminals of the terminal block. Due to the aging of the terminal block and the reduction of insulation, or the wrong position of the connecting piece or loop, the two power supplies are electrically cross-talked.

[0102] As Figure 14 shown, it is the low-pressure blocking telemetry signal circuit and the low-pressure blocking reclosing circuit. X06-69 and X06-70 are adjacent terminals on the terminal block, and J905 and 104 are the telemetry signal power supply and the control power supply respectively.

[0103] 1.4 The positive and negative poles of two DC power supplies come from different device power supplies

[0104] This situation is very likely to occur when multiple measurement and control devices are installed in the same protection panel and the alarm blocking information of each device is sent to each other. In the panel design of a 500 kV substation, generally, the reactive power compensation protection and measurement integrated devices under the same low-voltage bus are designed in the same panel; in a 500 kV substation, generally, the measurement and control devices on the three sides of the main transformer and the main body measurement and control device are also designed in the main transformer measurement and control panel, making it easy to have the above problems. In addition, for some low-voltage intervals with a large number of signals, the number of remote signal inputs of the supporting protection and measurement integrated device is insufficient, and it is necessary to borrow the inputs of the common measurement and control, which easily leads to the situation where the positive pole of the remote signal power supply comes from the protection and measurement integrated device of this interval, while the negative pole returns to the common measurement and control device.

[0105] As Figure 15 shown, it is the correct wiring method of the remote signal power supply.

[0106] As Figure 15 shown, on-site, it has happened that the positive power common terminal J701 of the positive power is the positive power provided by the measurement and control device 1, while the negative power side J901 returns to another measurement and control device.

[0107] As Figure 16 shown, in Figure 16 the wrong wiring shown, it will not affect the normal sending and resetting of signals. In fact, after the contact is closed, the phenomenon of electrical leakage has occurred. If the two groups of remote signal power supplies come from different DC buses, it will cause the mutual leakage between the two groups of DC power supplies. If a DC grounding occurs at this time, the two DC circuits will be pulled to one side at the same time. If the two groups of remote signal power supplies both come from the same group of DC buses, it will also cause adverse effects. For example, when this interval is out of service for maintenance, when the measurement and control power supply is disconnected, the potential of the other measurement and control power supply will be connected in series to the power-off circuit. On-site, it has happened that due to the negligence of the staff, after disconnecting the remote signal power supply of this interval, the potential was not measured and the secondary wiring was removed. In fact, the removed secondary wiring was still energized due to electrical leakage, and the energized secondary wiring was connected to the metal cabinet door, resulting in a DC grounding phenomenon. There have also been incidents of electric shock to personnel and insulating resistance measurement with live wires.

[0108] When measuring the potential during the pull-off test, after disconnecting the remote signal power supply of this interval, measure the potential of the remote signal power supply common terminal of this interval. Due to the large number of signals in the interval, generally, there are always signals that send messages by taking the normally closed contact. When the above-mentioned error occurs, the other remote signal power supplies will be connected in series to the remote signal power supply of this interval through the closed signal-sending contact, and the common terminal of the remote signal power supply of this interval will be negatively charged when measured.

[0109] 2. Summary of the method for detecting electrical leakage

[0110] As Figure 4 shown, taking power supply I as the research object, it is the work process of testing whether power supply I is electrically leaked with other power supplies.

[0111] Connect each test lead to the common terminal of the corresponding power supply in the secondary system. After powering on, the potential of each DC power supply can be measured. After checking that the potentials of all circuits are normal, assume to test whether there is power generation on the non-full-sequence relay nodes. After adjusting the specific setting conditions (the contacts of the non-full-sequence relay are closed, and the states of other contacts remain unchanged), disconnect the control power supply and press the confirmation button at the same time. If the control power supply is found to be without power during the measurement, it indicates that there is no electrical connection with other DC power supplies. If there is power, it means there is an electrical connection with other power supplies. To specifically analyze which one of the control power supply 2, telemetry signal power supply, and oscillograph power supply is involved in the electrical connection, it is necessary to conduct a pull-off test one by one. First, disconnect the control power supply 2 and press the corresponding confirmation button. If the control power supply 1 is without power at this time, it means that the previous potential was introduced by the control power supply 2. If there is still power, it can rule out the possibility of electrical connection from the control power supply 2, and it is necessary to continue to disconnect the telemetry signal power supply for testing... until the power supply involved in the electrical connection is found.

[0112] The overall idea of electrical connection detection is the pull-off method combined with the potential measurement method. Under the principle of the only variable, when a certain power supply is pulled off, if there is no power at the common terminal of this power supply, it means that there is no electrical connection phenomenon. If there is still power at the common terminal of this power supply, it is obvious that there is a connection with other power supplies, indicating the existence of an electrical connection defect.

[0113] (1) For the case where normally open contacts and normally closed contacts are taken respectively for two DC power supplies, before testing the electrical connection in this interval, judge the authenticity of the signal sent by the monitoring computer and judge whether there are any abnormal signs in the DC system.

[0114] (2) For the case where both power supplies take normally open contacts or normally closed contacts or the telemetry signal power supply is used crosswise. It is necessary to count which components have the above usage of contacts, and conduct test work on the above components one by one. Under the principle of "the only variable", close the nodes of the relay, and then use the pull-off method combined with the potential measurement method to find the electrical connection combinations one by one.

[0115] (3) For the cases of wrong wiring of adjacent terminals and the positive and negative poles of two DC power supplies coming from different device power supplies. There is no need to consider the contact position change. Using the simplest pull-off method combined with the potential measurement, the electrical connection defect in the circuit can be found.

[0116] Device for testing electrical connection:

[0117] Such as Figure 2As shown, the DC system of the substation can be divided into two groups of control power supplies, telemetry signal power supplies, and recording wave power supplies according to their functions. In the DC system of the substation, the rated value of the positive voltage is +110V, and the rated value of the negative voltage is -110V. The device contains 7 test leads, among which 1 is the ground wire, and the other 6 are connected to each power supply, respectively collecting the control 1 positive and negative common terminal power supplies, control 2 positive and negative common terminal power supplies, telemetry signal positive common terminal power supply, and recording wave positive common terminal power supply in the DC system of the substation. The test leads transfer the analog data to the DC voltage sampling unit and output it to the processor unit. The processor unit can display the actual potential of each power supply on the display. In addition, the processor can issue instructions on the working sequence. The operators need to conduct the power disconnection test for each power supply according to the instruction sequence and confirm that the corresponding power disconnection operation has been carried out by pressing the corresponding power button (for example, when the instruction requires the operator to disconnect the control one power supply, after the operator disconnects the control one power supply, it is fed back to the device by pressing the button). After a series of operations are completed, the processor unit sends the series power result to the display unit. The power supply unit supplies power to the processor, display, and other units of the device and has no connection with the power supply of the DC system of the substation.

[0118] Consistent with the potential measured by the multimeter, the series power device needs to sample up to 6 DC circuits at the same time, namely the positive and negative poles of control power supply I, the positive and negative poles of control power supply II, the positive pole of the telemetry signal power supply, and the positive pole of the recording wave power supply. Therefore, the device is designed with 7 test leads, among which 1 is grounded, and the other 6 are connected to the positive and negative poles of the above power supplies. The number of negative poles of the telemetry signal power supply and the recording wave power supply is large. Considering that the circuit is very simple, it is of little significance to collect the negative pole potential. The test leads and the inputs should correspond one by one.

[0119] Before conducting the test, first connect the test leads to the common terminal of the corresponding power supply and monitor the potential size in real time.

[0120] According to the set process, the device prompts to disconnect the corresponding power supply. After the staff disconnects the power supply according to the prompt, it is fed back to the device through the key. After the device receives the feedback, it detects the change in potential.

[0121] There may be three situations: one is no power, the second is that there is still normal DC voltage, and the third is that there is voltage but not the rated voltage. As long as there is power, it means that there is a series power phenomenon.

[0122] When the phenomenon of electrical leakage occurs between circuits, it is necessary to locate which power supply circuit is causing the problem. Therefore, it is necessary to disconnect other power supplies one by one until the electrical potential disappears. For example, after disconnecting the control I power supply, if it is found that there is still electricity at the common terminal of control I, then without restoring the control I power supply, disconnect the control II power supply and send feedback to the device through a button. After receiving the feedback, the device detects the change in electrical potential. If there is no electricity at the common terminal of control I, it indicates that there is electrical leakage between control I and control II power supplies. If there is still electricity at the control I power supply after disconnecting the control II power supply, it means that the electrical leakage is not caused by the control II power supply. It is necessary to disconnect the telemetry signal power supply in the same way until the power supply causing the electrical leakage is found.

[0123] The application of the device can, to a great extent, avoid the labor of manually measuring the electrical potential multiple times with a multimeter and also reduce the possibility of misoperation.

[0124] Taking the electrical leakage test process of power supply I as an example, the test processes of power supplies II and III are similar.

[0125] After the device of the present application has been operating confidentially for a period of time, the beneficial points feedback by on-site technical personnel are as follows:

[0126] The device includes a processor unit, a power supply unit, a DC voltage acquisition unit, a switch button, a display unit, signal acquisition test leads, a grounding test lead, and a confirmation button. The power supply unit is electrically connected to the switch button, the processor unit, and the display unit respectively. The DC voltage acquisition unit is electrically connected to each test lead, the processor unit, and the confirmation button respectively. The method is based on the above device and adopts the method of disconnecting circuits in combination with the method of testing electrical potential. When a power supply is disconnected, if there is no electricity at the common terminal of this power supply, it is known that there is no electrical leakage defect. If there is electricity at the common terminal of this power supply, it is known that there is an electrical leakage defect. It realizes the detection and knowledge of electrical leakage between DC power supply systems through the processor unit, the power supply unit, the DC voltage acquisition unit, the switch button, the display unit, the signal acquisition test leads, the grounding test lead, the confirmation button, etc.

[0127] The application of the device can, to a great extent, avoid the labor of manually measuring the electrical potential multiple times with a multimeter and also reduce the possibility of misoperation.

[0128] At present, the technical solution of the present invention has been pilot-tested, that is, a smaller-scale test before large-scale mass production of the product. After the pilot test is completed, user usage research has been carried out on a small scale, and the research results show that user satisfaction is relatively high. Now, preparations are underway for the formal production and industrialization of the product (including research on intellectual property risk early warning).

Claims

1. A secondary system series power test device for a substation, characterized in that: it includes a housing, a processor unit, a power supply unit, and a DC voltage acquisition unit arranged in the housing, as well as a switch button, a display unit, signal acquisition test leads, a grounding test lead, and a confirmation button arranged on the housing. The switch button is electrically connected to the power supply unit, the power supply unit is electrically connected to the processor unit, the power supply unit is electrically connected to the display unit, the signal acquisition test leads are electrically connected to the DC voltage acquisition unit, the DC voltage acquisition unit is electrically connected to the processor unit, the DC voltage acquisition unit is electrically connected to the grounding test lead, and the confirmation button is electrically connected to the processor unit; the signal acquisition test leads include the first to sixth test leads with the same structure, the DC voltage acquisition unit includes the first to sixth DC voltage acquisition units with the same structure, the confirmation button includes the first to sixth confirmation buttons with the same structure. One end of the first test lead passes through the housing and is electrically connected to the first DC voltage acquisition unit, one end of the second test lead passes through the housing and is electrically connected to the second DC voltage acquisition unit, one end of the third test lead passes through the housing and is electrically connected to the third DC voltage acquisition unit, one end of the fourth test lead passes through the housing and is electrically connected to the fourth DC voltage acquisition unit, one end of the fifth test lead passes through the housing and is electrically connected to the fifth DC voltage acquisition unit, one end of the sixth test lead passes through the housing and is electrically connected to the sixth DC voltage acquisition unit, one end of the grounding test lead passes through the housing and is electrically connected to each DC voltage acquisition unit, the first confirmation button is electrically connected to the processor unit, the second confirmation button is electrically connected to the processor unit, the third confirmation button is electrically connected to the processor unit, the fourth confirmation button is electrically connected to the processor unit, the fifth confirmation button is electrically connected to the processor unit, and the sixth confirmation button is electrically connected to the processor unit; it also includes the steps of a secondary system series power test method for a substation. The pull-off method is used in combination with the test potential method. When one power supply is pulled off, if there is no power at the common end of this power supply, it is known that there is no series power defect. If there is power at the common end of this power supply, it is known that there is a series power defect; specifically, it includes the following steps. Before the test is carried out, the grounding test lead is grounded, and the potential magnitude is monitored in real time; for the situation where normally open contacts and normally closed contacts are respectively taken for two DC power supplies, before the series power test at intervals, the authenticity of the signal sent by the monitoring machine is judged, and whether there are abnormal signs in the DC system is judged; for the situation where both power supplies take normally open contacts or normally closed contacts or the telemetry power supplies are cross-used, the contacts of the components are counted, and the test work is carried out one by one to close the nodes of the relay, and then the pull-off method is used in combination with the potential test method to find the series power combinations one by one; for the situation where adjacent terminals are wrongly wired and the positive and negative poles of two DC power supplies come from different device power supplies, the pull-off method is used in combination with the potential test to find out whether there is a series power defect in the circuit; when analyzing one contact, keep this variable as the only variable, and the states of other contacts in the circuit should remain unchanged and conducting.

2. The secondary system series power test device for a substation according to claim 1, characterized in that: It further includes a charging interface provided on the housing, and the charging interface is electrically connected to the power supply unit.

3. The series power test device for the secondary system of a substation according to claim 1, characterized in that: the display unit is a liquid crystal display.

4. The series power test device for the secondary system of a substation according to claim 1, characterized in that: the display unit is an LED display.

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