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EP-3988948-B1 - DISTRIBUTED INSULATION DETECTION DEVICE FOR MULTI-STAGE DC SYSTEM

EP3988948B1EP 3988948 B1EP3988948 B1EP 3988948B1EP-3988948-B1

Inventors

  • SU, Shuo
  • LIU, JIANYE
  • QIN, Shihao
  • SONG, Bao
  • YE, Yuhui
  • SHAO, MIN

Dates

Publication Date
20260506
Application Date
20200902

Claims (9)

  1. A distributed insulation detection device for a multi-stage direct current, DC, system, comprising: an intelligent control module, and a sampling module, a basic insulation combination module and an intelligent resistance switching network module connected with the intelligent control module; wherein: the sampling module is configured to collect voltage data and/or leakage current data of the multi-stage DC system, and to transmit the voltage data and/or leakage current data to the intelligent control module; the basic insulation combination module is configured to detect a ground insulation fault of the multi-stage DC system; the intelligent resistance switching network module is configured to adjust a resistance value of the distributed insulation detection device of the multi-stage DC system; and the intelligent control module is configured to process the voltage data and/or leakage current data, and control to adjust the basic insulation combination module and the intelligent resistance switching network module; characterized in that : the intelligent control module is configured to control resistance values of the basic insulation combination module and the intelligent resistance switching network module, to adjust a total balanced resistance of the distributed insulation detection device for the multi-stage DC system; wherein the basic insulation combination module and the intelligent resistance switching network module are connected in series through a respective correspondence; wherein the basic insulation combination module comprises: a first balanced resistor pair RD11 and RD12, a second balanced resistor pair RD21 and RD22, and a first switching switch pair KD21 and KD22; wherein: the second balanced resistor pair RD21 and RD22 are respectively corresponding to and connected in parallel with the first switching switch pair KD21 and KD22; and the first balanced resistor pair RD11 and RD12 are respectively corresponding to and connected in series with the second balanced resistor pair RD21 and RD22 and the first switching switch pair KD21 and KD22 that are respectively connected in parallel, and are further respectively connected in series to a positive lead to ground and a negative lead to ground of the DC bus; wherein the intelligent resistance switching network module comprises: at least one pair RD31 and RD32 of first functional resistor pairs, and a corresponding first functional switch pair KD31 and KD32; and the first functional resistor pair RD31 and RD32 are respectively corresponding to and connected in parallel with the first functional switch pair KD31 and KD32, and are further respectively connected in series to a positive lead to ground and a negative lead to ground of the DC bus.
  2. The distributed insulation detection device for the multi-stage DC system according to claim 1, wherein the sampling module, the basic insulation combination module and the intelligent resistance switching network module are respectively connected to a DC bus of the multi-stage DC system in any order.
  3. The distributed insulation detection device for the multi-stage DC system according to claim 2, wherein the sampling module at least comprises any one of a high-precision resistance voltage divider detection circuit and an operational amplifier gain detection circuit.
  4. The distributed insulation detection device for the multi-stage DC system according to claim 2, wherein the intelligent control module comprises a microcontroller unit, MCU, chip, and peripheral communication, sampling and control circuits.
  5. The distributed insulation detection device for the multi-stage DC system according to claim 1, wherein: in a case that only the first balanced resistor pair RD11 and RD12 are connected into the basic insulation combination module, the basic insulation combination module is configured to detect a single-ended ground insulation fault by a balanced bridge method; and in a case that the first balanced resistor pair RD11 and RD12, the second balanced resistor pair RD21 and RD22, and the first switching switch pair KD21 and KD22 are all connected into the basic insulation combination module, the basic insulation combination module is configured to detect a double-ended ground insulation fault by an unbalanced bridge method.
  6. The distributed insulation detection device for the multi-stage DC system according to claim 5, wherein: resistance values of the first balanced resistor pair RD11 and RD12 are equal and determined by the voltage data and/or leakage current data of the multi-stage DC system; and resistance values of the second balanced resistor pair RD21 and RD22 are equal, and are equal to or greater than four times the resistance values of the first balanced resistor pair RD11 and RD12.
  7. The distributed insulation detection device for the multi-stage DC system according to claim 1, wherein control signals of the at least one pair of the first functional switch pairs KD31 and KD32 and the first switching switch pair KD21 and KD22 are all controlled by the intelligent control module, and the control modes comprise a joint control for switch pairs and/or an independent control for switch pairs.
  8. The distributed insulation detection device for the multi-stage DC system according to claim 1, wherein for the at least one pair of the first functional switch pairs KD31 and KD32 and the first switching switch pairs KD21 and KD22, switching devices in switch pairs comprise at least any one of a relay, a triode, an optocoupler, and a MOS transistor.
  9. The distributed insulation detection device for the multi-stage DC system according to any one of claims 1-6, wherein the resistance values of the at least one pair of the first functional resistor pairs RD31 and RD32 are equal, and a series-parallel combination value of all functional resistors configured in the same multi-stage DC system is greater than 20 times resistance values of first balanced resistor pair RD11 and RD12 in the basic insulation combination module.

Description

TECHNICAL FIELD Embodiments of the present disclosure include, but are not limited to, the field of high-voltage direct current power supply system technology, and specifically include, but are not limited to, a distributed insulation detection device for a multi-stage DC system. BACKGROUND Due to the superiority of direct current (DC) power supply, a high-voltage direct current (HVDC) system has developed rapidly in fields of communication base stations, new energy and automotive electronics in recent years. The power supply of core server rooms of an Internet data center (IDC) has gradually developed from uninterruptible power system/uninterruptible power supply (UPS) to HVDC. Different from the conventional 48V communication power supply, the HVDC power supply system uses a suspended power supply, and the positive and negative busbars to ground are required to ensure a certain insulation degree. Serious damage may be caused to equipment and personal safety due to an insulation failure. The Chinese patent application CN109765495A discloses a insulation detection circuit and method. The Chinese patent application CN103091596A discloses a balancing double-switching circuit and insulation detection device and method based on the same. SUMMARY The present invention relates to a distributed insulation detection device for a multi-stage DC system, as defined in claim 1. Other features and corresponding beneficial effects of the present disclosure are described in the later part of the specification, and it should be understood that at least part of the beneficial effects become obvious from the description in the specification of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS The present disclosure will be further described below with reference to the accompanying drawings and embodiments. The accompanying drawings are as below. FIG. 1 is a schematic architecture diagram of a typical application of a power supply and distribution system for a multi-stage DC power supply.FIG. 2 is a schematic architecture diagram of a distributed insulation detection device for a multi-stage DC system according to a first embodiment of the present disclosure.FIG. 3 is a schematic diagram of a circuit topology structure consisting of a series connection between a basic insulation combination module and an intelligent resistance switching network module according to the first embodiment of the present disclosure.FIG. 4 is a schematic architecture diagram of a typical distributed DC power supply and distribution system according to a second embodiment of the present disclosure.FIG. 5 is a simplified schematic diagram of an insulation detection device with a single DC power supply system being parallel to a single power distribution system output according to a third embodiment of the present disclosure.FIG. 6 is a simplified schematic diagram of an insulation detection device with a single DC power supply system being parallel to three power distribution system outputs according to a fourth embodiment of the present disclosure.FIG. 7 is a simplified circuit diagram of a distributed insulation detection device for a multi-stage DC system which uses an unbalanced bridge insulation detection method to detect a double-ended grounding fault in a first state according to the fourth embodiment of the present disclosure.FIG. 8 is a simplified circuit diagram of the distributed insulation detection device for the multi-stage DC system which uses the unbalanced bridge insulation detection method to detect the double-ended grounding fault in a second state according to the fourth embodiment of the present disclosure.FIG. 9 is a simplified circuit diagram of the distributed insulation detection device for the multi-stage DC system which uses the unbalanced bridge insulation detection method to detect the double-ended grounding fault in a third state according to the fourth embodiment of the present disclosure. DETAILED DESCRIPTION In order to make objectives, technical solutions and advantages of the present disclosure clearer, some embodiments of the present disclosure will be explained below in detail with reference to accompanying drawings and specific embodiments. It should be understood that specific embodiments described here only explain the disclosure but do not constitute a limitation on the disclosure. Inventors noted that: the conventional insulation monitoring technology based on a balanced bridge theory is only aimed at a single DC system, without considering a parallel connection of multiple insulation detection devices, and would no longer adapt to the increasingly diversified power supply and distribution systems. The larger the resistance of a balanced bridge, the larger the deviation amplitude of the voltage to ground and the higher the sensitivity of an insulation detection. However, the larger the resistance of the balanced bridge, the more likely the voltage to ground deviates in response to the insulation decre