CN105807187A - Single-phase ground-fault assist detection device - Google Patents

Abstract

The invention discloses a single-phase ground fault auxiliary detection device, which is suitable for the single-phase ground fault auxiliary detection of a 10kV distribution network neutral point ungrounded system, comprising a device body and a device controller, which are connected through an aviation plug. In the normal operating state, the controller can monitor the system voltage and current in real time online. Once a single-phase ground fault occurs, the controller can control the contactor to switch on according to the set pulse sequence to form a loop between the non-fault phase and the fault phase. When the fault indicator detects the pulse current and voltage drop, the fault indicator flips the card and uploads the fault information to the master station and the designated mobile phone of the staff. The invention cooperates with the fault indicator system to realize the effective location of the single-phase grounding fault, and has positive significance for reducing the number of power outages, shortening the power outage time, improving the reliability of power supply, and ensuring the stable operation of the line.

Description

A single-phase ground fault auxiliary detection device

technical field

The invention relates to the field of power systems, in particular to the single-phase ground fault location problem of a distribution network neutral point ungrounded system.

Background technique

The neutral point of the medium-voltage distribution network is not grounded. When a single-phase ground fault occurs, the fault indicator of the corresponding line cannot be effectively flipped due to the small short-circuit current, so that the line patrol and substation operators on duty can deal with the fault in time. come to have a big impact.

In the past, improving the power supply reliability of the distribution network can usually be achieved by changing the wiring mode of the 10kV line, strengthening the insulation level of the line, replacing aging equipment in a timely manner, strengthening the business training of the operators of the 10kV line, standardizing the selection of user equipment, and comprehensively arranging power outages. Switch power supply operations, and implement measures such as live distribution network work. These measures have reduced the number of power outages to a certain extent and improved the reliability of power supply. However, with the continuous development of our country's economy and society, and the continuous improvement of people's living standards, power users have also put forward higher requirements for the reliability of power supply.

Now use modern electronics, computer, communication and network technology to integrate the online data and offline data, distribution network data and user data, power grid structure and geographic graphics of the distribution network to form a complete automation system, and realize the distribution network and distribution network. The modernization of the monitoring, protection, control, and power distribution management of the equipment under normal operation and accident status.

One of the important functions is the location of single-phase ground fault in distribution network. Using the cooperation of single-phase ground fault auxiliary detection device and fault indicator system, the single-phase ground fault of distribution network can be effectively and quickly located, quickly isolated, and non-destructive. Functions such as fast restoration of power supply in the fault area improve the reliability of power supply and ensure the stable operation of the line.

Contents of the invention

The invention discloses an auxiliary detection device for single-phase grounding, which is based on the principle of detecting single-phase grounding faults by an injection method. Cooperating with the fault indicator system, it can realize the function of fast location of single-phase ground fault in 10kV distribution network neutral point ungrounded system.

Technical scheme of the present invention is:

A single-phase ground fault auxiliary detection device, the present invention is characterized in that it includes a body 2 and a controller 8 connected thereto through an aviation plug; wherein, the body 2 includes a high-voltage contactor 3 and high-voltage wiring connected to the high-voltage contactor 3 respectively Terminal 1, grounding resistor 4, grounding resistor 4 is connected to grounding device 6 through CT5;

The high-voltage contactor 3 of the present invention is divided into two AC phases; the high-voltage contactor 3 is respectively provided with an electrical lock and a mechanical lock to prevent the two AC phases from contacting at the same time and short-circuiting.

The voltage monitored by the controller of the present invention is 57.7V through the PT7 in the normal operation state of the system; when a single-phase ground fault occurs, the controller monitors that the voltage of the fault phase decreases and the voltage of the non-fault phase increases.

The controller 8 of the present invention is provided with manual switching and automatic switching functions.

The device of the invention is suitable for single-phase grounding fault location in a 10kV distribution network neutral point ungrounded system. One of the primary terminals 1 is connected to the AC two-phase of the 10kV distribution network; during normal operation, the controller can monitor the system voltage and current in real time online, once a single-phase ground fault occurs, the controller can detect when the voltage reaches the controller voltage start-up setting value , control the high-voltage contactor 3, put it into operation according to the set pulse sequence, and form a loop between the non-fault phase and the fault phase ground point. When the fault indicator detects the pulse current and voltage drop, the fault indicator flips the card and uploads the fault information to the master station and the designated mobile phone. The device cooperates with the fault indicator to realize the effective positioning of the single-phase ground fault, which is of positive significance for reducing the number of power outages, shortening the power outage time, improving the reliability of power supply, and ensuring the stable operation of the line.

Description of drawings

Fig. 1 is a schematic diagram of the device of the present invention.

detailed description

See Figure 1, a single-phase ground fault auxiliary detection device, the present invention is characterized in that it includes a main body 2 and a controller 8 connected thereto through an aviation plug; Connected high-voltage terminal 1, grounding resistor 4, grounding resistor 4 is connected to grounding device 6 through CT5; PT7 is respectively connected to high-voltage terminal 1 and controller 8; CT5 is also connected to controller 8.

The high-voltage contactor 3 of the present invention is divided into two AC phases; the high-voltage contactor 3 is respectively provided with an electrical lock and a mechanical lock to prevent the two AC phases from contacting at the same time and short-circuiting.

The voltage monitored by the controller of the present invention is 57.7V through the PT7 in the normal operation state of the system; when a single-phase ground fault occurs, the controller monitors that the voltage of the fault phase decreases and the voltage of the non-fault phase increases.

The controller 8 of the present invention is provided with manual switching and automatic switching functions.

Among them, the terminal 1 on the primary side is connected to the AC two-phase of the 10kV distribution network; the controller 8 is connected to the main body 2 through the aviation plug. During normal operation, the controller 8 monitors the voltage and current of the system through PT7 and CT5; Single-phase ground fault (instantaneous or permanent fault), the controller detects the voltage and current changes of the faulty phase and the non-faulty phase, when the voltage detected by the controller 8 reaches the controller voltage start-up fixed value, the logic judgment function is started, The controller sends a signal to the main body, after a certain delay, the main body is put into the high-voltage contactor 3, the opening and closing of the contactor is controlled by the pulse sequence set by the program, and the phase A contactor or one of the phase C contactors is put into contact. A circuit is formed between the non-faulty phase and the faulty phase-to-ground point through the voltage of the non-faulty phase being higher than that of the faulty phase. When the fault indicator detects the pulse current and voltage drop, the fault indicator flips the card and uploads the fault information to the master station and the designated mobile phone.

The on-duty personnel can promptly organize personnel to repair the fault according to the fault location information, which is of positive significance for quickly troubleshooting and restoring power supply.

Claims (4)

1. a singlephase earth fault auxiliary detection device, it is characterised in that: include body 2 and the controller 8 being attached thereto by aviation plug；Wherein, body 2 includes high voltage connector 3 and the high-voltage connection terminal 1 being connected respectively, grounding resistor 4 with high voltage connector 3, and grounding resistor 4 is connected with grounding device 6 by CT5；It is provided with PT7 to be connected with high-voltage connection terminal 1 and controller 8 respectively；CT5 is also connected with controller 8.

2. a kind of phase-to-ground fault detection auxiliary device according to claim 1, it is characterised in that: high voltage connector 3 is divided into AC biphase；High voltage connector 3 is respectively provided with electric blocking and mechanical latching, it is prevented that the biphase contact simultaneously of AC is short-circuited.

3. a kind of phase-to-ground fault detection auxiliary device according to claim 1, it is characterised in that: controller is 57.7V by the PT7 voltage monitored when system normal operating condition；When there is singlephase earth fault, monitoring control devices reduces to faulted phase voltage, and healthy phases voltage raises.

4. a kind of phase-to-ground fault detection auxiliary device according to claim 1, it is characterised in that: controller 8 is double is provided with manual switching and automatic switching function.