CN203798982U - Switch electric life test loop for extra-high voltage substation reactive compensation - Google Patents

Abstract

The utility model provides a switch electric life test loop for extra-high voltage substation reactive compensation. The secondary side high voltage terminal of a first transformer is connected with a protection circuit breaker, a first electric reactor, a closing switch, a first auxiliary switch, an operation switch, a first capacitor, a resistor, the secondary side of a second transformer and the secondary side low voltage terminal of the first transformer in series in sequence to form a loop. The common node of the protection circuit breaker and the first electric reactor is connected with the primary side low voltage terminal of the second transformer. The secondary side low voltage terminal of the first transformer is connected with the primary side high voltage terminal of the second transformer and a grounding point. A switch to be tested is bridged between the grounding point and the common node of the first auxiliary switch and the operation switch. The high voltage terminal of the switch to be tested is connected with a second auxiliary switch, a second electric reactor, a second capacitor and the grounding point in series in sequence to form a loop. The test loop can save test capacity; the closing-separating operation of the switch can be carried out in one test without switching the test loop frequently; and thus the test efficiency is improved.

Description

Life test circuit of switching power for reactive power compensation in UHV substation

technical field

The utility model belongs to the high-power test field of a high-voltage switch, in particular to a switch electrical life test circuit for reactive power compensation of an ultra-high voltage substation.

Background technique

The reactive power profit and loss in the UHV AC transmission system has relatively large changes, and switching the capacitor bank on the tertiary side of the main transformer is an important means of reactive power regulation. At present, the rated voltage of the capacitor bank in the UHV project reaches 110kV, and the capacity of a single capacitor reaches 210Mvar or even higher. The special switch for reactive power compensation also uses 126kV switchgear for the first time. The rated voltage of the capacitor bank is high and the capacity is large, and the dedicated switch needs to be frequently operated. , the operating conditions are severe.

Increased breaking current, pre-breakdown and ablation during closing process, frequent operation and other factors make the operating conditions of special circuit breakers very harsh. Insulation performance has caused hidden dangers to the safe operation of UHV power grids. Therefore, it is particularly urgent to carry out the electrical life test of the special switching capacitor bank, but the current national standard does not have this test item, and under the condition of limited laboratory capacity, it is difficult to carry out this test, even if it is carried out to achieve "close-open "The operation requires frequent switching of the test circuit, and the test efficiency is low.

Utility model content

Aiming at the defects of the prior art, the purpose of this utility model is to propose an electrical life test circuit for switching capacitor banks with special switches without frequent switching of the test circuit to improve test efficiency.

In order to solve the above technical problems, the utility model adopts the following technical solutions to realize.

A switching electrical life test circuit for reactive power compensation in UHV substations, comprising: a network power supply, a first transformer, first, second, and third voltage sensors, and first, second, and third current sensors,

The high voltage terminal on the secondary side of the first transformer is sequentially connected with the protective circuit breaker, the first reactor, the closing switch, the first auxiliary switch, the operating switch, the first capacitor, the resistor, the secondary side of the second transformer and the first transformer The low-voltage side of the secondary side is connected in series to form a loop;

The common node between the protective circuit breaker and the first reactor is connected to the primary side low-voltage end of the second transformer;

The secondary side low-voltage end of the first transformer is respectively connected to the second transformer primary-side high-voltage end and a grounding point;

The switch to be tested is connected between the grounding point and the common node of the first auxiliary switch and the operating switch; form a loop in series;

The first voltage sensor is set at the common node of the first auxiliary switch and the operating switch, the second voltage sensor is set at the high voltage end of the secondary side of the second transformer, and the third voltage sensor is set at the common node of the first reactor and the closing switch ;

The first current sensor detects the current passing through the first auxiliary switch, the second current sensor detects the current passing through the switch to be tested, and the third current sensor detects the output current of the second transformer.

Further, the secondary side of the second transformer is connected in parallel with a first lightning arrester.

Further, a second lightning arrester is connected in parallel at both ends of the first capacitor, and a discharge resistor is connected in parallel at both ends of the first capacitor.

Further, a protective gap is connected in parallel between the common node of the closing switch and the first auxiliary switch and the grounding point.

Compared with the prior art, the beneficial effects of the utility model are:

The utility model uses the circuit composed of the second capacitor, the second reactor, the second auxiliary switch and the switch to be tested to carry out the closing test; the first transformer is used to provide most of the breaking test current, and the second transformer provides a small part of the breaking test current. Current and full recovery voltage; the test power supply with limited capacity can be used to conduct the special switch switching capacitor bank test, which saves the test capacity; and the "on-off" operation of the special switch can be carried out in one test without frequent switching of the test circuit. Improve the efficiency of the test.

Description of drawings

Fig. 1 is that the utility model carries out the schematic diagram of the electrical life test of the special switch switching capacitor group;

In the figure: S-network power supply; T1-first transformer; BD-protective circuit breaker; Lc-first reactor; HK-closing switch; FK1-first auxiliary switch; CD-operation switch; Cv-first capacitor ; Rv-resistor; Rf-discharge resistor; P2-second arrester; P1-first arrester; T2-second transformer; Ch-second capacitor; BQ-guard gap; V1-first voltage sensor; V2-second voltage sensor; V3-third voltage sensor; A1-first current sensor; A2-second current sensor; A3-third current sensor.

Detailed ways

Referring to Figure 1, the second capacitor Ch and the second reactor Lh are charged to the second capacitor Ch before the test, and the combination of the two is used as the power supply during the closing test, S is the network power supply, and the primary side of the first transformer T1 is connected to the power supply S Parallel connection, the secondary side high voltage end of the first transformer T1 is connected in series with the protective switch BD, the primary side of the second transformer T2 is anti-parallel connected with the secondary side of the first transformer T1 through the protective switch BD, the secondary side low voltage end of the first transformer T1 is grounded, the first The two lead-out lines on the secondary side of the transformer T1 are used as the output terminals of the current source during the breaking test, and the two lead-out lines on the secondary side of the second transformer T2 are used as the output terminals of the voltage source during the breaking test.

The output terminal of the closing test power supply is sequentially connected in series with the second auxiliary switch FK2 and the switch to be tested SP to form a loop to provide high-frequency inrush current during closing and closing. The closing switch HK, the first auxiliary switch FK, the switch to be tested SP, and the secondary side low-voltage end of the first transformer T1 form a loop, which provides most of the test current for the breaking test, and the output terminal of the breaking test voltage source is connected in series with the resistor Rv , the first capacitor Cv, the operating switch CD, the switch to be tested SP, and the secondary side low-voltage end of the second transformer T2 form a loop to provide part of the test current and the full recovery voltage for the breaking test.

The first lightning arrester P1 connected in parallel to the secondary side of the second transformer T2 is used to limit the overvoltage on the secondary side of the second transformer T2; the second lightning arrester P2 connected in parallel to both ends of the first capacitor Cv is used to limit the overvoltage across the first capacitor Cv Voltage; a protective gap BQ is connected in parallel between the common node of the closing switch HK and the first auxiliary switch FK and the grounding point, which is used to limit the overvoltage on the secondary side of the first transformer T1.

The first voltage sensor V1 is set at the common node of the first auxiliary switch FK1 and the operation switch CD, the second voltage sensor V2 is set at the high voltage end of the secondary side of the second transformer T2, and the third voltage sensor V3 is set at the first reactor Lc and the closing Gate switch HK common node; the first current sensor A1 detects the current passing through the first auxiliary switch FK1, the second current sensor A2 detects the current passing through the switch SP to be tested, and the third current sensor A3 detects the output current of the second transformer T2.

When conducting the test, first charge the second capacitor Ch to the rated closing test voltage. At this time, the closing switch HK, the first auxiliary switch FK1, the switch to be tested SP, the second auxiliary switch FK2, and the operating switch CD are all in the opening state. According to the test procedure, close the second auxiliary switch FK2 first, and then close the switch SP to be tested. The switch SP to be tested is closed to meet the inrush current of the predetermined peak value and frequency requirements. After 0.1 seconds, the second auxiliary switch FK2 and the switch SP to be tested are separated brake. According to the test procedure, close the protection switch BD, the first auxiliary switch FK1, and the switch SP to be tested in sequence, and then close the closing switch HK, and the switch SP to be tested is closed with no load; Close the operation switch CD, the current provided by the switch SP to be tested through the first transformer T2 and the second transformer T2, this current is the rated breaking current, after 0.1 second, the first auxiliary switch FK1 and the switch SP to be tested are opened, At this time, the switch SP to be tested breaks the rated current, and both ends of the switch SP to be tested bear the recovery voltage required by the standard. 0.3 seconds after the switch SP to be tested is turned off, the operation switch CD, the closing switch HK, and the protection switch BD are opened. This test is over, and all equipment returns to the initial state to prepare for the next test.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present utility model and not to limit them. The utility model has been described in detail in conjunction with the above embodiments, and those of ordinary skill in the art should understand that: those skilled in the art Personnel can still modify or equivalently replace the specific implementation of the present utility model, but these modifications or changes are all within the protection scope of the pending claims.

Claims (4)

1. A switching power life test circuit for reactive power compensation in UHV substations, characterized in that the test circuit includes: network power supply, first transformer, first, second, third voltage sensors and first, second 2. The third current sensor, The high voltage terminal on the secondary side of the first transformer is sequentially connected with the protective circuit breaker, the first reactor, the closing switch, the first auxiliary switch, the operating switch, the first capacitor, the resistor, the secondary side of the second transformer and the first transformer The low-voltage side of the secondary side is connected in series to form a loop; The common node between the protective circuit breaker and the first reactor is connected to the primary side low-voltage end of the second transformer; The secondary side low-voltage end of the first transformer is respectively connected to the second transformer primary-side high-voltage end and a grounding point; The switch to be tested is connected between the grounding point and the common node of the first auxiliary switch and the operating switch; form a loop in series; The first voltage sensor is set at the common node of the first auxiliary switch and the operating switch, the second voltage sensor is set at the high voltage end of the secondary side of the second transformer, and the third voltage sensor is set at the common node of the first reactor and the closing switch ; The first current sensor detects the current passing through the first auxiliary switch, the second current sensor detects the current passing through the switch to be tested, and the third current sensor detects the output current of the second transformer. 2. The test circuit according to claim 1, characterized in that, the secondary side of the second transformer is connected in parallel with a first lightning arrester. 3. The test circuit according to claim 1, characterized in that a second lightning arrester and a discharge resistor are connected in parallel at both ends of the first capacitor. 4. The test circuit according to claim 1, characterized in that a protective gap is connected in parallel between the common node of the closing switch and the first auxiliary switch and the grounding point.