CN102088186A - Method for carrying out failure protection and logic optimization on UHVDC (Ultra-High Voltage Direct Current) neutral bus switch - Google Patents

Abstract

The invention discloses a method for carrying out failure protection and logic optimization on a UHVDC (Ultra-High Voltage Direct Current) neutral bus switch. In the operating process of double poles, once the neutral bus switch of a failure pole fails, firstly the operation of detecting whether a basis pole isolation signal exists is carried out, the operation is completed if the basis pole isolation signal does not exist, and the following steps are carried out if the basis pole isolation signal exists: 1, sending a command to make the neutral bus switch coincided and locked; 2, switching off an instation neutral bus earthed switch; 3, separating an isolation switch near the neutral bus switch of the failure pole; and 4, after the isolation switch is separated and is in place, switching off the instation earthed switch. After the processing method is adopted, when the neutral bus switch fails, the failure pole can still be isolated, so that the operation stoppage of the double poles is effectively avoided.

Description

Extra-high voltage direct-current neutral bus malfunctioning switch protection logic optimization method

Technical field

The present invention relates to the action policy of extra-high voltage DC transmission system neutral bus malfunctioning switch protection and adopt this tactful protective device.

Background technology

In extra-high voltage DC transmission system; because there is zero crossing in direct current unlike alternating current; the cutout of dc circuit breaker is limited in one's ability and depend on self subsidiary loop; in order to carry out the Fault Isolation operation in the DC engineering; generally carry out utmost point isolated operation at dc circuit breaker of utmost point neutral bus side configuration; it is the neutral bus switch (NBS) among Fig. 1; in the middle of during sexupara wiretap operation failure; just during malfunctioning switch; if do not adopt suitable processing mode; may cause bipolar stoppage in transit, neutral bus malfunctioning switch protection criterion is as follows:

Neutral bus switch NBS receives trip signal, and the IDNE electric current is above certain certain value after a period of time, and the protection of neutral bus malfunctioning switch is moved.

IDNE is abutted against the extreme direct current in ground for the neutral bus side.

After the neutral bus malfunctioning switch protection action, need to overlap the neutral bus switch for preventing that the neutral bus switch from damaging, after being overlapped and lock as the neutral bus switch, fault can't be isolated, and may cause the non-fault utmost point to be stopped transport.Extra-high voltage direct-current is because transmission capacity is huge, in case bipolar stoppage in transit takes place, very big to the impact of AC system, the interruption of through-put power also can bring massive losses to national economy.

In DC transmission system, middle NBS shown in Figure 1, NBGS, MRTB is a dc switch, possesses certain cutout ability, P1_WN_Q11, P1_WN_Q12, P2_WN_Q11, P2_WN_Q12 are isolating switch, do not possess the cutout ability.

Summary of the invention

The present invention seeks to: the optimization method of protection logic when proposing extra-high voltage direct-current neutral bus malfunctioning switch; when the bipolar operation of extra-high voltage DC transmission system; during fault utmost point generation neutral bus malfunctioning switch; carry out the fault utmost point by the interim conveyance capacity of earth point in the current conversion station and isolate, effectively avoid bipolar stoppage in transit.

Technical scheme of the present invention is: the guard method of a kind of direct current transportation fault utmost point neutral bus malfunctioning switch is characterized in that: in bipolar running, to the neutral bus malfunctioning switch of the fault utmost point, finish the fault utmost point according to the following step and isolate:

Step 1: issuing an order allows fault utmost point neutral bus switch NBS overlap and locking;

Step 2: neutral bus earthed switch NBGS in the closed current conversion station;

Step 3: separate near the isolating switch (as P1_WN_Q11) of fault utmost point neutral bus switch NBS;

Step 4: after isolating switch separately puts in place, disconnect earthed switch NBGS in the current conversion station.

Wherein, in bipolar running,, prevent that the failure protection malfunction from causing stopping transport in case the neutral bus malfunctioning switch of the fault utmost point should detect earlier whether this utmost point isolation signals is arranged; If this utmost point isolation signals do not arranged then no longer carry out above-mentioned four steps; Go on foot above-mentioned four steps if this utmost point isolation signals is arranged then carry out, as shown in Figure 1.

Utmost point isolation signals is carried out isolated operation according to the fault type needs with the fault utmost point after being meant direct current protecting action, usually DC engineering to the utmost point isolate be defined as separately high voltage bus isolating switch and middle sexupara switch (NBS) with and adjacent isolating switch.

By aforesaid operations, can effectively carry out the isolation of the fault utmost point, guarantee the power delivery of the non-fault utmost point.

The invention has the beneficial effects as follows: when fault utmost point generation neutral bus malfunctioning switch, if another utmost point is in running status, because the neutral bus switch of the fault utmost point can't disconnect, will cause another utmost point (the non-fault utmost point) stoppage in transit, finally cause bipolar stoppage in transit, when the neutral bus malfunctioning switch, also can isolate after adopting processing method of the present invention, effectively avoid bipolar stoppage in transit the fault utmost point.

Description of drawings

Fig. 1 is an extra-high voltage direct-current change of current low-pressure end main wiring diagram;

Fig. 2 is Fault Isolation step 1 of the present invention state diagram;

Fig. 3 is Fault Isolation step 2 of the present invention state diagram;

Fig. 4 is Fault Isolation step 3 of the present invention state diagram;

Fig. 5 is Fault Isolation step 4 of the present invention state diagram;

Among Fig. 1～Fig. 5: IDNE is that neutral bus is abutted against earth polar side electric current; NBS is the neutral bus switch; NBGS is earthed switch in the station; MRTB is the metallic return change over switch; P1_WN_Q11, P1_WN_Q12, P2_WN_Q11, P2_WN_Q12 are the neutral bus isolating switch.

Fig. 6 is a Fault Isolation flow chart of the present invention.

Embodiment

The K point breaks down and is example among following Fig. 2; earth fault takes place in the utmost point one K point when bipolar operation; the utmost point one protection action; carry out utmost point isolated operation; the neutral bus switch (NBS) that separates the fault utmost point (being the utmost point one) in the utmost point isolation processes; in case the neutral bus switch is failure separately; neutral bus malfunctioning switch protection action, the neutral bus switch overlaps and locking, and this moment is as shown in Figure 3; the utmost point two is as the non-fault utmost point; can provide electric current to the fault point, the utmost point two constitutes the loop by the earth point of fault point and earth electrode and to the station, if do not carry out respective handling; for preventing that fault point K from working the mischief to the person and equipment in standing, and needs the non-fault utmost point of stopping transport.

After the neutral bus malfunctioning switch protection action; this utmost point is carrying out utmost point isolated operation simultaneously; according to earthed switch (NBGS) in the closed station of operation shown in Figure 3; the utmost point two constitutes the loop by three earth points and to the station after the interior earthed switch closure of standing; interior earth point in station this moment and fault point parallel running; bear most of electric current; earth electrode is because circuit is longer; line resistance is bigger; it is less to bear electric current under the parallel running mode; because earth point and fault point parallel running in the station; can separate P1_WN_Q11 and P1_WN_Q12 isolating switch by operation shown in Figure 4; after the breakpoint isolated fault extremely by P1_WN_Q11 and P1_WN_Q12 isolating switch, earthed switch NBGS (as shown in Figure 5) in the disjunction station again.The continuation that guarantees the utmost point two normally moves.

Claims (1)

1. an extra-high voltage direct-current neutral bus malfunctioning switch is protected the logic optimization method, it is characterized in that: in bipolar running, in case the neutral bus malfunctioning switch of the fault utmost point, finishing the fault utmost point according to the following step isolates, and earlier detect whether this utmost point isolation signals is arranged, if do not have this utmost point isolation signals then finish; If this utmost point isolation signals arranged then carry out following steps:

Step 1: issuing an order allows fault utmost point neutral bus switch NBS overlap and locking;

Step 2: neutral bus earthed switch NBGS in the closed current conversion station;

Step 3: separate near the isolating switch of fault utmost point neutral bus switch NBS;

Step 4: after isolating switch separately puts in place, disconnect earthed switch NBGS in the current conversion station.

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