CN114895126A - Direct current system electrical parallel connection detection device and method based on uninterruptible power supply technology - Google Patents
Direct current system electrical parallel connection detection device and method based on uninterruptible power supply technology Download PDFInfo
- Publication number
- CN114895126A CN114895126A CN202210483310.8A CN202210483310A CN114895126A CN 114895126 A CN114895126 A CN 114895126A CN 202210483310 A CN202210483310 A CN 202210483310A CN 114895126 A CN114895126 A CN 114895126A
- Authority
- CN
- China
- Prior art keywords
- direct current
- power supply
- current system
- parallel connection
- connection detection
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/10—Measuring sum, difference or ratio
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Supply And Distribution Of Alternating Current (AREA)
Abstract
The invention relates to a direct current system electrical parallel connection detection device and method based on an uninterruptible power supply technology. The device comprises a direct current uninterrupted power supply with an isolation transformer, a measuring unit and a logic controller, wherein the direct current uninterrupted power supply with the isolation transformer is used for realizing the direct current system electrical parallel connection detection and supplying power to a direct current load, the measuring unit is used for realizing the measurement of the voltage difference between two inputs of the direct current load, and the logic controller is used for realizing the control of the direct current uninterrupted power supply with the isolation transformer and the measuring unit and the direct current system electrical parallel connection detection. The invention can be suitable for solving the parallel connection problem of the direct current system under the uninterrupted state.
Description
Technical Field
The invention belongs to the field of electric power equipment maintenance, and particularly relates to a direct current system electrical parallel connection detection device and method based on an uninterruptible power supply technology.
Background
The direct current system is used as an important system for supplying power to a control loop, a relay protection device and an outlet loop of a transformer substation, and in large and medium-sized transformer substations, the direct current system is used as an 'active pulse and a capillary vessel' in the transformer substation and is distributed at each corner in the substation.
The relay protection (secondary equipment) is used as a first line of defense of a power grid, takes an important role of rapidly cutting off and isolating faults and is a '360-degree safety guard' of a power system. The direct current system in the transformer substation is an important system for supplying power to the relay protection device, the control loop and the outlet loop of the relay protection device, and influences the correctness of protection actions, so that the direct current system is an important system for influencing the stable operation of a power grid. Generally, the problem of the direct current system directly affects the stability and safety of the overall operation of the power grid.
The parallel connection problem of the direct current system means that electrical connection exists between two direct current loops which should independently operate, and the connection form of the direct current loops is that the direct current loops are connected in the same polarity and in the different polarity. The loop problem is mainly caused by reasons such as load shedding in construction and operation, and is also one of the reasons for relay protection misoperation, namely that a fire disaster is caused by the possibility of generating loop current, the direct current air-to-open level difference is caused to be matched and failed, the service life of a storage battery is shortened, and the protection is rejected.
In view of the particularity of the dc system of the substation, the present invention will first be briefly described, as shown in fig. 1. Since each dc device may affect the operation of the power system, it requires that the power supply be radial, i.e. no parallel connection problem (only a single power supply for each dc load) is allowed.
The system network pair based on fig. 1 illustrates a variety of problematic dc system electrical parallel connection problems. The first merging problem is illustrated in fig. 2. In fig. 2, the positive and negative poles of two different dc loads are connected by the same pole, and the power supply network is normal without load failure, so this problem is difficult to be found, and especially the problem of the single power homopolar loop 2 cannot be found even when the load fails because it has no connection of the electrical loop, and also interferes with the power stability of the normal load (the problem is also present in the case of dual power supplies, and is not described again).
In the case of the single power supply inverter circuit of fig. 3, the problem is very easy to be found because of the occurrence of an electrical short circuit, but in the case of the dual power supply inverter circuit of fig. 4, the problem becomes very dangerous, and when the two-stage dc bus switch is not closed, the dc system is normally operated and there is no trouble in the load. When the split operation of the direct-current bus is converted into the closed-loop operation, usually one of the power supplies fails, and the system stability is seriously reduced, and at the moment, if the bus switch is closed, the power switch is directly tripped, so that the total-station direct-current system of the transformer substation is damaged, and the power supply protection equipment is completely shut down.
The fault cause is usually caused by the capacity increase and extension of a transformer substation, the probability of the existence of a parasitic loop is increased linearly due to the various complexity of the direct current load, and the key point of the invention is how to find and eliminate the problems under the condition of no power failure.
Disclosure of Invention
The invention aims to provide a direct current system parallel connection detection device and method based on an uninterrupted power supply technology, which can be applied to solving the parallel connection problem of the direct current system under the uninterrupted power state.
In order to achieve the purpose, the technical scheme of the invention is as follows: a direct current system electrical parallel connection detection device based on an uninterrupted power supply technology comprises a direct current uninterrupted power supply with an isolation transformer, a measurement unit and a logic controller;
the direct current uninterruptible power supply with the isolation transformer comprises an isolation transformer, a one-way bridge type full-control circuit and a detection circuit, wherein the isolation transformer is connected with the output of the station alternating current power supply, the one-way bridge type full-control circuit is used for realizing controllable direct current voltage output, and the detection circuit is used for monitoring the voltage of a direct current load of a direct current system;
the measuring unit is used for measuring the voltage difference of a direct current load of a direct current system and comprises a first differential sampling circuit and a second differential sampling circuit, wherein two inputs of the first differential sampling circuit are used as a first pair of measuring nodes S 1 、S 2 Two inputs of the second differential sampling circuit are used as a second pair of measuring nodes S 3 、S 4 For dual-power direct current system, short circuit S 1 And S 3 ；
The logic controller is used for realizing the power supply access of the direct current uninterrupted power supply with the isolation transformer and realizing the electrical parallel connection detection of the direct current system according to the measurement result of the measurement unit.
In an embodiment of the present invention, the first differential sampling circuit includes first to fourth resistors and an operational amplifier, and one end of the first resistor is used as a measurement node S 1 The other end of the first resistor is connected with the inverting input end of the operational amplifier and is connected with the first output end of the operational amplifier through the second resistor, and one end of the third resistor is used as a measurement node S 2 The other end of the third resistor is connected with the non-inverting input end of the operational amplifier and is connected with the second output end of the operational amplifier through the fourth resistor, and the two output ends of the operational amplifier are connected with the logic controller; the connection structure of the second differential sampling circuit is the same as that of the first differential sampling circuit.
In an embodiment of the present invention, the manner for the logic controller to implement the electrical parallel connection detection of the dc system according to the measurement result of the measurement unit is as follows: according to the voltage difference of the direct current load of the direct current system measured by the measuring unit, if the voltage difference is fixed, the direct current system is electrically connected in parallel, and if the voltage difference is floating, the direct current system is not electrically connected in parallel.
The invention also provides a direct current system electrical parallel connection detection method based on the uninterrupted power supply technology, which is characterized in that the direct current system electrical parallel connection detection device based on the uninterrupted power supply technology is connected to a direct current load of the direct current system needing electrical parallel connection detection, a switch between a power supply and the direct current load of the direct current system is cut off, the direct current system electrical parallel connection detection device based on the uninterrupted power supply technology supplies power to the direct current load, the voltage difference of two inputs of the direct current load is measured by a measuring unit at the moment, if the voltage difference is fixed, the direct current system has electrical parallel connection, and if the voltage difference is floating, the direct current system does not have electrical parallel connection.
Compared with the prior art, the invention has the following beneficial effects: the invention can find and eliminate the problem of the parallel connection of the direct current system under the condition of no power failure.
Drawings
Fig. 1 is a dc system network.
Fig. 2 is a single power supply homopolar shunt loop.
Fig. 3 is a single power supply heteropolar parallel circuit.
FIG. 4 is a dual power supply circuit with two different electrodes connected in parallel
Fig. 5 is a dc ups with isolation transformer.
Fig. 6 shows a measuring unit.
FIG. 7 is a logic controller function flow.
Fig. 8 is a dc system electrical parallel connection detection device based on the uninterruptible power supply technology according to an embodiment of the present invention.
Detailed Description
The technical scheme of the invention is specifically explained in the following by combining the attached drawings.
The invention relates to a direct current system electrical parallel connection detection device based on an uninterruptible power supply technology, which comprises a direct current uninterruptible power supply with an isolation transformer, a measurement unit and a logic controller, wherein the measurement unit is used for measuring the direct current uninterruptible power supply;
the direct current uninterruptible power supply with the isolation transformer comprises an isolation transformer, a one-way bridge type full-control circuit and a detection circuit, wherein the isolation transformer is connected with the output of the station alternating current power supply, the one-way bridge type full-control circuit is used for realizing controllable direct current voltage output, and the detection circuit is used for monitoring the voltage of a direct current load of a direct current system;
the measuring unit is used for measuring the voltage difference of a direct current load of a direct current system and comprises a first differential sampling circuit and a second differential sampling circuit, wherein two inputs of the first differential sampling circuit are used as a first pair of measuring nodesPoint S 1 、S 2 Two inputs of the second differential sampling circuit are used as a second pair of measuring nodes S 3 、S 4 For dual-power direct current system, short circuit S 1 And S 3 ；
The logic controller is used for realizing the power supply access of the direct current uninterrupted power supply with the isolation transformer and realizing the electrical parallel connection detection of the direct current system according to the measurement result of the measurement unit.
The invention also provides a direct current system electrical parallel connection detection method based on the uninterrupted power supply technology, which is characterized in that the direct current system electrical parallel connection detection device based on the uninterrupted power supply technology is connected to a direct current load of the direct current system needing electrical parallel connection detection, a switch between a power supply and the direct current load of the direct current system is cut off, the direct current system electrical parallel connection detection device based on the uninterrupted power supply technology supplies power to the direct current load, the voltage difference of two inputs of the direct current load is measured by a measuring unit at the moment, if the voltage difference is fixed, the direct current system has electrical parallel connection, and if the voltage difference is floating, the direct current system does not have electrical parallel connection.
The following are specific embodiments of the present invention.
The invention designs a direct current system electrical parallel connection detection device based on an uninterruptible power supply technology, the device can be divided into three blocks as shown in the following figure, the first block figure 5 is a direct current uninterruptible power supply with an isolation transformer, and the device can be used for realizing power supply switching of equipment. The second block fig. 6 is a measurement unit that can be used to implement the measurement of the voltage difference, and the third block is a logic controller that is used to control the device functions, as shown in fig. 7.
In the design of fig. 5, the ac power supply for the station is usually 380V and 220V, the "floating ground" strategy is realized by the isolation transformer, the controllable rectification is realized by the unidirectional bridge type full-control circuit, and the output dc voltage can be set to 10-300V. The voltage monitoring of the direct current load can be realized through the detection circuit, the functions of reverse connection prevention and reverse power supply prevention are achieved, and P1 and P2 represent two ends of a power supply.
In the design of FIG. 6, a differential sampling circuit is used to enable measurement of the voltage difference。S 1 、S 2 Represents a pair of measurement nodes, S 3 、S 4 Represents a pair of measuring nodes, and can be short-circuited S for a dual-power supply measuring scheme 1 And S 3 And the node is used as a public end to measure.
In the design of FIG. 7, the functional flow diagram is as follows:
the mechanism for judging whether the electrical parallel connection exists is that the direct current uninterrupted power supply and the direct current power supply system power supply of the transformer substation are both independent voltage sources without electrical connection under normal conditions, the voltage difference between the direct current uninterrupted power supply and the direct current power supply system power supply of the transformer substation is floating, and if the fixed voltage difference (the voltage of the direct current power supply system or zero) exists, the direct current uninterrupted power supply and the direct current power supply system power supply of the transformer substation exist electrical connection.
In case confirm that it has the concatenation problem, accessible fixed pressure differential's the condition, easy judgement is that there is homopolar concatenation or heteropolar concatenation problem, and guarantees to get rid of the trouble under the incessant operational aspect of all equipment, and very big reduction cost of overhaul and the influence that has a power failure are a breakthrough innovation technique, effectively improve the security that the direct current system of transformer substation overhauld.
As shown in fig. 8, for example, a dual power parallel circuit is used, a device for automatically detecting the parallel connection of the loads of the dc system is connected to a suspected load, a switch between the dc system and the load of the substation is cut off, the device for automatically detecting the parallel connection of the loads of the dc system supplies power to the load, and S is measured at this time 1 S 2 （S 3 S 4 ) And judging whether a parallel connection problem exists between the voltage difference and the direct current power supply system voltage or not by judging whether a fixed voltage difference (the direct current power supply system voltage or zero) exists between the voltage difference and the direct current power supply system voltage or not. If the voltage is zero, S 1 In the branch and S 2 The branch has a parallel connection problem. If the voltage is the DC power supply system voltage, S 1 Branch and S 2 The other loop of the branch is connected in parallel.
The above are preferred embodiments of the present invention, and all changes made according to the technical scheme of the present invention that produce functional effects do not exceed the scope of the technical scheme of the present invention belong to the protection scope of the present invention.
Claims (4)
1. A direct current system electrical parallel connection detection device based on an uninterrupted power supply technology is characterized by comprising a direct current uninterrupted power supply with an isolation transformer, a measurement unit and a logic controller;
the direct current uninterruptible power supply with the isolation transformer comprises an isolation transformer, a one-way bridge type full-control circuit and a detection circuit, wherein the isolation transformer is connected with the output of the station alternating current power supply, the one-way bridge type full-control circuit is used for realizing controllable direct current voltage output, and the detection circuit is used for monitoring the voltage of a direct current load of a direct current system;
the measuring unit is used for measuring the voltage difference of a direct current load of a direct current system and comprises a first differential sampling circuit and a second differential sampling circuit, wherein two inputs of the first differential sampling circuit are used as a first pair of measuring nodes S 1 、S 2 Two inputs of the second differential sampling circuit are used as a second pair of measuring nodes S 3 、S 4 For dual-power direct current system, short circuit S 1 And S 3 ；
The logic controller is used for realizing the power supply access of the direct current uninterrupted power supply with the isolation transformer and realizing the electrical parallel connection detection of the direct current system according to the measurement result of the measurement unit.
2. The apparatus according to claim 1, wherein the first differential sampling circuit comprises a first resistor, a second resistor, an operational amplifier, and a measurement node S at one end of the first resistor 1 The other end of the first resistor is connected with the inverting input end of the operational amplifier and is connected with the first output end of the operational amplifier through the second resistor, and one end of the third resistor is used as a measurement node S 2 The other end of the third resistor is connected with the non-inverting input end of the operational amplifier and is connected with the second output end of the operational amplifier through the fourth resistor, and the two output ends of the operational amplifier are connected with the logic controller; the connection structure of the second differential sampling circuit is the same as that of the first differential sampling circuit.
3. The uninterruptible power supply technology-based direct current system electrical parallel connection detection device according to claim 1, wherein the manner in which the logic controller implements direct current system electrical parallel connection detection according to the measurement result of the measurement unit is as follows: according to the voltage difference of the direct current load of the direct current system measured by the measuring unit, if the voltage difference is fixed, the direct current system is electrically connected in parallel, and if the voltage difference is floating, the direct current system is not electrically connected in parallel.
4. A direct current system electrical parallel connection detection method based on the uninterrupted power supply technology based on the device of any one of claims 1-3 is characterized in that the direct current system electrical parallel connection detection device based on the uninterrupted power supply technology is connected to a direct current load of a direct current system needing electrical parallel connection detection, a switch between a power supply and the direct current load of the direct current system is cut off, the direct current system electrical parallel connection detection device based on the uninterrupted power supply technology supplies power to the direct current load, the voltage difference of two inputs of the direct current load is measured through a measuring unit at the moment, if the voltage difference is fixed, the direct current system is electrically connected in parallel, and if the voltage difference is floating, the direct current system is not electrically connected in parallel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210483310.8A CN114895126A (en) | 2022-05-06 | 2022-05-06 | Direct current system electrical parallel connection detection device and method based on uninterruptible power supply technology |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210483310.8A CN114895126A (en) | 2022-05-06 | 2022-05-06 | Direct current system electrical parallel connection detection device and method based on uninterruptible power supply technology |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114895126A true CN114895126A (en) | 2022-08-12 |
Family
ID=82719703
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210483310.8A Pending CN114895126A (en) | 2022-05-06 | 2022-05-06 | Direct current system electrical parallel connection detection device and method based on uninterruptible power supply technology |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114895126A (en) |
-
2022
- 2022-05-06 CN CN202210483310.8A patent/CN114895126A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US10998756B2 (en) | Microgrid system and method for managing malfunction | |
| WO2022121431A1 (en) | Medium-voltage photovoltaic grid-connected inverter system and photovoltaic power generation system | |
| CN110794293A (en) | Method for detecting automatic nuclear capacity switch state of storage battery | |
| CN102074994B (en) | Charging device of direct-current (DC) system | |
| CN102411120B (en) | Earth line selection device for converting station direct current system | |
| CN103683188A (en) | Safety detection apparatus of solar energy inverter | |
| JP3933974B2 (en) | Voltage fluctuation compensation device | |
| CN109100616A (en) | A kind of detection method with the single-phase power-off of grounding transformer | |
| CN114895126A (en) | Direct current system electrical parallel connection detection device and method based on uninterruptible power supply technology | |
| CN110967576A (en) | Anti-islanding operation detection method under distributed power supply grid-connected mode | |
| WO2021244242A1 (en) | Transient voltage locking module for power distribution terminal | |
| CN114336980A (en) | Intelligent cloud power distribution method and system based on instruction transmission | |
| CN114123497A (en) | Intelligent bus-tie monitoring device of low-voltage direct-current power supply system for station and control method | |
| CN209117811U (en) | The control system of balance bridge | |
| CN208369218U (en) | A kind of sensitive loads voltage disturbance governing system | |
| CN207588552U (en) | Ups power failure detector | |
| CN217545579U (en) | Power differential protection device of rail transit rectifier unit | |
| CN217506082U (en) | DC power supply fault monitoring system for factory | |
| CN216530696U (en) | Direct current power supply system | |
| JPH0150168B2 (en) | ||
| Swetha et al. | Autonomous Active Grid islanding and DGs outage detection in a $\mu\mathrm {G} $ utilizing Goertzel Algorithm in collaboration with Fuzzy Inferencing System | |
| CN113726000B (en) | Power supply device and power supply method thereof | |
| CN219980426U (en) | DC protection power supply system | |
| CN110165641A (en) | The coincidence method of dc circuit breaker in flexible HVDC transmission system | |
| CN219960114U (en) | DC ring network protection device and DC power supply system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |