JPS58116017A - Dc ground circuit detector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a DC grounding circuit detection device capable of accurately detecting a grounded feeder in a DC power source 111fiIIR having a plurality of feeders.

Technical background of the invention and its problems As a conventional DC grounding circuit detection device in a DC electric fJl system, the positive bus bar and the negative bus bar are each grounded with the same resistance, and either the positive bus bar or the negative bus bar is grounded. When a ground fault occurs in a ground fault, the ground fault current is detected by the District Public Prosecutors Office.
m electric appliances are commonly used. And the DC current fjK
In a case where there are many feeders in the system, when a grounding accident occurs, the grounding will be resolved when the power to each feeder is disconnected and the power to the feeders that are grounded is turned off. This was used to determine which feeders were grounded.

However, it is not allowed to simply turn off the power in feeders where important equipment will stop if the power is turned off, and in general, it is not allowed to turn off the power easily, and in general, it is not allowed to turn off the power easily in case of important equipment stopping. This method had the disadvantage that it took a long time to detect the feeder.

For this reason, in recent DC power systems, in addition to the above-mentioned busbar collective ground detection relay, direct circuit detection devices that can also detect grounded feeders at the same time have been widely adopted. . #! 1tiil is a system diagram of a DC power supply equipped with this revised DC grounding circuit detection device, and as before, the positive bus 2 and negative bus 3 connected to the DC power supply 1 are connected with a resistor 4 of the same value. , the intermediate potential is grounded via the bus collective grounding detection relay 5, and at the same time the general load 6 is grounded.
The feeder 7 to the load 9 and the feeder 10 to the load 9 which are grounded by the capacitors Jla and 8b are grounded separately, taking advantage of the fact that when the feeder 10 to the load 9 is grounded, the difference between the inflow and outflow current is equal to the ground current. Detecting DC vibration Ohji detection @
lla and llb are provided so that grounded feeders can be detected at the same time.

As shown in FIG. 1, a feeder 7 to a general load 6, a feeder 10, etc., a load 9 and a capacitor 8 in the load @ to remove AC noise.

One point 1 where the feeder 10 which is grounded at 8b coexists
When grounding occurs as shown in IM13,
The busbar collective grounding detection relay 5 detects that the positive busbar 2- has turned into farmland, and outputs an Il signal. At the same time, feeder 7
The DC grounding circuit detector 11m installed in the DC grounding circuit detector 11m has the excitation winding Ji14iy14b of opposite polarity and is excited by the AC power supply 15 until it is sufficiently saturated.
Since the currents flowing through 8!16 and 17 are unbalanced by the ground current, an output voltage is generated between the output terminals 18 and 19, indicating that the feeder 7 has been grounded. However, in this case, in the feeder 10, the electric charge stored in the capacitor 8a whose positive potential side is grounded is used as a power source to connect the capacitor 8a and the winding 2 of the DC transformer.
0. DC positive bus 2. Winding 16 of the DC current transformer of the direct i-ground circuit detector 11a. A discharge current flows through the circuit of ground 13, earth, and capacitor 8&. Since the DC grounding circuit detector 11b installed in the feeder 0 is the same as the DC grounding circuit detector lla installed in the feeder 7, this discharge current causes the +m current R of the DC grounding circuit detector 11b to
The current flowing through the windings 20 and 21 of the diaphragm becomes unbalanced,
It is detected and @ is displayed indicating that the Iik ground has also occurred on the feeder IO.

In actuality, in a DC power supply system having a large number of feeders, the loads connected to 20 to 40% of the feeders are grounded by capacitors. Therefore, in the DC power supply system equipped with the conventional DC grounding circuit detection device shown in Figure 1, if a grounding fault occurs at a certain feeder, the capacitor discharge circuit will be activated in almost all of the feeders whose loads are grounded by the capacitor. formed,
A discharge current flows, and the current flowing across the DC current transformer of the DC grounding circuit detector becomes unbalanced, so the display indicates that a grounding fault has occurred even though there is no actual grounding. The invention had the disadvantage that it was not possible to accurately detect which feeder had actually touched the ground. Even in the case where there are feeders that are grounded by a load or a capacitor in the ljk current system, if an instantaneous grounding fault occurs, it is possible to accurately detect which feeder is actually grounded. 41t'Ij of the 〇 invention aimed at providing a direct tlt grounding 12J path detection device! In a DC source system with many feeders, the positive bus and negative bus are connected via the same value of resistance, and the bus has a contact that closes when the positive bus # is grounded and a contact that closes when the negative bus # ground. In contrast to the conventional IJT current contact M circuit detection device, which consists of a relay and a 1-lit flow ground circuit detector, which is installed for each feeder and detects and displays the grounded feeder when a grounding accident occurs on a feeder. , the above-mentioned - current ground circuit detector is improved, and a contact point that closes when the feeder is in the positive/exceeding position 1ij11i11 edge ground and a contact point that closes when the feeder is in the negative position - are provided separately in the warehouse, and the aforementioned bus bar collective grounding detection circuit is provided. The contacts of the electrical appliance and the contacts of the improved l1ft ground circuit detector are put together at a positive potential of nil, 1
Divide into 2 groups: a contact group that closes when d1 and a contact group that closes when negative potential l1il is grounded, and for each group, connect the contacts of the motherboard collective earthing detection relay, the #LIL grounding-road detection gain contact, and the indicator light. Or in series with an auxiliary relay.
A separate display panel is provided to connect this, so that even if a feeder to a load that is grounded by a capacitor is included, the grounded feeder can be accurately displayed on the display panel.

Embodiment of the Invention A second embodiment of the DC grounding circuit detection device according to the present invention will be described below.
This will be explained with reference to FIGS.

Figure 2 is a DC power supply system diagram equipped with a DC grounding circuit detection device according to the present invention. A resistor 4 of the same value is connected to the positive bus 2 and negative bus @ 3 connected to the DC power supply l, and the intermediate potential point is grounded via the bus collective grounding detection joint *4m5,
When the positive quantity -2 side is grounded, one point 5a is closed, and the negative bus line 31
When 111 is grounded, the checkpoint 5b is closed to indicate grounding, and the feeder 7.10 to each load o, ij, 30 is
, 31 separately describes the ground circuit detection method 32, which detects grounding by using the inflow and outflow of current when grounded.
a, 32b, and 32c are provided to also detect a grounded feeder, which is the same as the conventional DC grounding circuit detector shown in Figure 1. However, in this invention, the DC grounding circuit detector 32a.

Improvements have been made to 32b and 32e.

DC*m circuit detection 132a, 32b, 32c are all l
jlml, the DC grounding circuit detector 32a installed in the feeder 7 will be explained.

Direct ft, ii! ! In the ground (b) road detector 32&,
The excitation windings 33m and 33b have opposite polarities and are excited by the AC power supply 34 until they are sufficiently saturated, and no output voltage appears while the currents flowing through the windings of the DC f current generator are balanced. . However, if grounding occurs at one point on the footer, the current flowing through the DC current transformer's edges is, i'z will be unbalanced by the ground fault current, so the output terminal 35.
36, a voltage with a jill wave number twice the frequency of the AC power supply 34 can be seen.

Conventional llk flow grounding circuit detection winding 1 shown in 11ilI3
1a uses this output voltage as it is to display ground detection, but in this invention, this output voltage is
Depending on the direction in which the ground fault current flows, when grounding on the positive potential line side, the voltage characteristics will be as shown in Figure #13, and when grounding is on the negative potential iuw side, the voltage characteristics will be as shown in Figure 4. A contact 37m that closes when the potential M is grounded and a contact 38JL that closes when the negative potential line is grounded are provided separately. In addition, if a grounding accident occurs at one point on feeder 7, capacitor 8m, 8m
In the DC grounding circuit detector 32b installed at the feeder lO to the load 9 which is grounded at b, the electric charge stored in the capacitors 8a or C and 8b is detected at @@20.21 of the DC current transformer. Since the current flows in the opposite direction to that when the feeder 10 is grounded, the contact 37b closes when the positive potential line is grounded.
is closed when the negative potential line is grounded, and the contact 38b, which is closed when the negative potential line is grounded, is closed when the positive potential I11 is grounded.

lI! Figure i5 is a schematic diagram of the display panel of the DC grounding (B) path detection device according to the present invention.
a and contact 5b, which closes when the negative bus is grounded, are connected in parallel,
A DC grounding circuit detector 32m is installed in each feeder in series with the contact 5a.

Contacts 37a and 37b, which close when the positive potential line side of 32b and 32c are grounded, are connected in parallel to each other, and the contact 5b is connected in series with the DC grounding wire installed in each feeder. Circuit detector 32 m, 32 b.

A contact 38a that closes when the member potential line lI1 of 32c is grounded.

Contacts 37a, 37b, . . ., which are connected in parallel with each other, are connected in series with indicator lights or auxiliary relays 391, respectively. 39 b.
..., contacts 38a, 38b...
・Indicator light or auxiliary relay 40 J in series with each
In a DC power supply system that has many feeders as shown in Figure 2, if a grounding accident occurs on the positive potential line side of feeder 7, the The DC grounding circuit detector 32 & installed in the feeder 7 where the accident occurred has a positive potential III.
The grounding contact 37a closes, and at the same time the mother rock mass grounding detection relay i
Positive mother of #5 * Ground contact 5a is idle 0 Therefore, on the display panel shown in Fig. 5, the indicator light or auxiliary electric device 39a is lit or excited, and the positive potential LIKII of the feeder 7 is grounded. This will be displayed and alerted. Ill, 1, when grounding occurs on the negative potential w side of Feetuff, the negative bus grounding contact 5b and the negative potential M*grounding contact 8m close, and the indicator light or auxiliary relay @ 40 m lights up on the display panel. Or it is excited and the negative potential of the feeder 7 is 1! Displays and warns that grounding has occurred. The positive potential of feeder 7 &III
GC! When a ground fault occurs, the busbar collective grounding detection relay 5 closes the positive 1IiI grounding contact 5a, but the feeder 1 to the load 9, which is grounded by the capacitors 8m and 8b, closes.
0, in the DC ground circuit detector 32b installed therein, the contact 38b corresponding to the negative potential ms ground is closed, and the contact 37b corresponding to the positive potential lji pseudo-ground is not closed. Therefore, the indicator light or auxiliary relay associated with feeder 10 is not illuminated or energized, so that there is no grounding at other feeders at the feeder to the capacitor grounded load, as in conventional DC grounding circuit detection devices.

Effects of the Invention The DC grounding circuit detection device according to the present invention, as mentioned in the previous section for one example, applies a positive potential to the DC grounding circuit detector installed in each feeder of a DC power supply system having a large number of feeders. Contact that closes when line side is grounded and negative potential line @
Separate contacts that close when grounded are provided, and on the display panel,
Including the contacts of the bus collective grounding detection relay, connect them separately into two groups: a contact group that closes when the positive bus system is grounded, and a contact group that closes when the negative bus system is grounded, and connect them to a load that is grounded with a capacitor. Even if there is a feeder, only the feeder that is actually grounded is displayed accurately, so like the conventional DC grounding circuit detection device, especially the feeder to the capacitor grounded load, other feeders, - Grounding at the feeder is no longer incorrectly displayed as grounding at your own feeder, and the accident point on the ground is displayed accurately.
This has the effect of making it easier to search for accident points.

[Brief explanation of the drawing]

Fig. 1 is a DC power supply system diagram equipped with a conventional DC grounding circuit detection device, and Fig. 2 is a DC power supply system diagram equipped with a DC grounding detection device according to an embodiment of the present invention. Figures 143 and 4 are the positive potential lines of the DC grounding circuit detector. The respective output voltage waveforms when the negative potential line is grounded, and FIG. 5 is a circuit diagram of the display panel of the DC grounding circuit detection device in one embodiment of the present invention. 1... DC power supply, 2... Positive bus, 3... Negative bus,
4...Resistor, 5...Bus bar collective grounding detection relay, 5a
...Positive quantity - contact closed when grounded, 5b... contact closed when negative bus line grounded, 6°9.30...load, 7,10.31...
Feeder, 11a, llb, 32a, 32b, 32c・
- DC grounding circuit detector, 37a, 37b... contact closed when positive potential line is grounded, 38 a, 38 b... contact closed when negative potential line is grounded, 39a, 39b, 40m, 40b...
Indicator light or auxiliary relay. (7317) Agent Patent attorney Kensuke Norichika (and 1 other person) Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] In a DC power supply system 6 having a plurality of feeders including a feeder to a load grounded by a capacitor, the positive quantity line and the negative bus line are connected through a resistance of the same value, Positive return - mm
A power source having a contact that closes when the negative bus is grounded and a contact that closes when the negative bus is grounded.
Connect the contact point of the IL ground circuit detector, the bus bar collective Im ground detection chain electric controller, and the direct IL ground circuit detector to the positive potential side Wl.
Divided into 21 groups, 1 contact group that closes when standby and a contact group that closes when negative potential side is grounded, and in each group, contacts of mother-collective earth detection relay, direct #1 ground-path detection contact, and indicator light or auxiliary relay. and a display panel connected in series.