CN205283138U - Cascade compensation device based on holographic control strategy - Google Patents

Abstract

A series compensation device based on a holographic control strategy, including a series compensation capacitor, a damper, and a current transformer connected in series in the system line, and the series compensation capacitor is connected in series with the damper and then respectively connected with a fast vacuum switch, a zinc oxide component, The bidirectional thyristor group and the voltage collector are connected in parallel. The series compensation capacitor is connected in series in the line during normal operation. Once a short-circuit fault occurs on the line other than the outgoing terminal L2, the voltage at both ends of the series compensation capacitor quickly exceeds the threshold voltage of the low residual voltage zinc oxide component, and the low residual voltage zinc oxide component is turned on. Limit the voltage to the range allowed by the series compensation capacitor. When the voltage collector detects that the voltage exceeds the set threshold, it immediately sends a conduction pulse to the bidirectional thyristor valve group. Under the action of the residual voltage of the zinc oxide component, the bidirectional thyristor valve Group conduction, the zinc oxide components will be withdrawn together with the series compensation capacitor.

Description

A Series Compensation Device Based on Holographic Control Strategy

technical field

The utility model relates to the technical field of electric power equipment, in particular to a series compensation device based on a holographic control strategy.

Background technique

In order to solve the power supply quality problems such as low voltage at the end of the line caused by the long power supply radius, centralized parallel compensation or decentralized parallel compensation and series compensation technologies are mainly used in the market. Parallel compensation technology is considered from the perspective of voltage regulation. Because parallel capacitors increase the power factor of the load side to reduce the flow of reactive power to increase the voltage at the receiving end, frequent grouping operations or removal operations are required according to load changes, and the capacity is proportional to the square of the voltage. In direct proportion, when the grid voltage drops, the voltage regulation effect drops significantly, and the capacitor voltage drop in the series compensation device directly compensates the line voltage drop, and the voltage regulation effect is automatically and continuously adjusted as the load changes. Dynamic compensation can be realized, and the effect is obviously better than that of the parallel compensator.

However, most of the series compensation devices currently on the market rely on overcurrent to judge external short circuits. The control information is relatively simple, and the voltage at the end of the line cannot be monitored, causing resonance in the power line and causing a large-scale paralysis of the power supply grid. The failure will inevitably lead to the failure of the series capacitor bank to exit. If the failure of the series compensation capacitor bank or the deterioration of the zinc oxide component occurs, it will directly affect the normal operation of the system.

Utility model content

The technical problem to be solved by the utility model is to provide a series compensation device based on a holographic control strategy with reasonable structural design and high safety.

The technical problem to be solved by the utility model adopts the following technical solutions to realize:

A series compensation device based on a holographic control strategy, including a series compensation capacitor, a damper and a current transformer connected in series in the system line, the series compensation capacitor is connected in series with the damper, and then respectively connected with a fast vacuum switch, a zinc oxide component, The bidirectional thyristor group and the voltage collector are connected in parallel. The series compensation capacitor is connected in series in the line during normal operation. Once a short-circuit fault occurs on the line other than the outgoing terminal L2, the voltage at both ends of the series compensation capacitor quickly exceeds the threshold voltage of the low residual voltage zinc oxide component, and the low residual voltage zinc oxide component is turned on. Limit the voltage to the range allowed by the series compensation capacitor. When the voltage collector detects that the voltage exceeds the set threshold, it immediately sends a conduction pulse to the bidirectional thyristor valve group. Under the action of the residual voltage of the zinc oxide component, the bidirectional thyristor valve Group conduction, the zinc oxide components will be withdrawn together with the series compensation capacitor.

A current collector is connected in series on the branch of the zinc oxide component to provide a leakage current signal of the zinc oxide component during normal operation. When the leakage current exceeds the first set threshold, a fault alarm signal is sent, and when the leakage current exceeds the second set threshold, Initiates the withdrawal of the series compensation capacitor bank.

The function of the damper is to limit the discharge current of the capacitor and prevent the contact welding of the rapid vacuum switch.

The current transformer provides the working current signal of the series compensation device. When an external short circuit fault occurs, the controller uses a fast algorithm to issue a closing command to the fast vacuum switch in about 2ms. The inverse time-lag characteristic of the allowable over-current value of the capacitor bank is delayed to issue a fast vacuum switch to issue a closing command. The holographic control under short-circuit fault is composed of overvoltage, inverse time overcurrent and overcurrent quick-break protection, which greatly improves the operation reliability of the series compensation device.

The beneficial effects of the utility model are: the utility model has a reasonable structural design, and the holographic control under short-circuit fault is constituted by overvoltage, inverse time limit overcurrent and overcurrent quick-break protection, which greatly improves the action reliability of the series compensation device.

Description of drawings

Fig. 1 is the electrical principle wiring diagram of the utility model.

detailed description

In order to make the technical means, creative features, goals and effects achieved by the utility model easy to understand, the utility model will be further elaborated below in conjunction with specific illustrations.

Referring to Figure 1, a series compensation device based on a holographic control strategy includes a series compensation capacitor 1, a damper 2 and a current transformer 3 connected in series between the system line L1 and L2 terminals, and the series compensation capacitor 1 and damper 2 After being connected in series, they are respectively connected in parallel with the fast vacuum switch 4, the zinc oxide component 5, the bidirectional thyristor group 6 and the voltage collector 7. The series compensation capacitor 1 is connected in series in the line during normal operation. Once a short-circuit fault occurs on the line other than the outlet terminal L2, the voltage across the series compensation capacitor 1 quickly exceeds the threshold voltage of the low residual voltage zinc oxide component 5, and the low residual voltage zinc oxide component After 5 is turned on, the voltage is limited to the range allowed by the series compensation capacitor 1. The voltage collector 7 detects that the voltage exceeds the set threshold and immediately sends a conduction pulse to the bidirectional thyristor valve group 6. Under pressure, the bidirectional thyristor valve group 6 is turned on, and the zinc oxide component 5 and the series compensation capacitor 1 are withdrawn together.

A current collector 8 is connected in series on the branch of the zinc oxide component 5, which is used to provide the leakage current signal of the zinc oxide component during normal operation. When the leakage current exceeds the first set threshold, a fault alarm signal is sent out; Initiates the withdrawal of the series compensation capacitor bank. The function of the damper 2 is to limit the discharge current of the capacitor and prevent the contact welding of the rapid vacuum switch. The current transformer 3 provides the working current signal of the series compensation device. When an external short-circuit fault occurs, the controller uses a fast algorithm to issue a closing command to the fast vacuum switch in about 2ms. The inverse time-lag characteristic of the group allowable over-current value is delayed to issue a fast vacuum switch to issue a closing command. The holographic control under short-circuit fault is composed of overvoltage, inverse time overcurrent and overcurrent quick-break protection, which greatly improves the operation reliability of the series compensation device.

working principle

1. When the system is in normal operation, the fast vacuum switch is opened, and the capacitor of the series compensation device is connected in series in the system line. Through the principle that the direction of the capacitive voltage drop on the capacitor in the line is opposite to that of the inductive voltage drop in the line, the voltage at the end of the line is compensated. the goal of.

2. When a short circuit occurs at the end of the line, the voltage across the capacitor of the series compensation device immediately exceeds the threshold voltage of the low residual voltage zinc oxide component connected in parallel with it, and the zinc oxide component is turned on to limit the voltage across the capacitor to a safe range. When the voltage collector detects that the zinc oxide conducts for a period of time, the controller sends a closing command of the fast vacuum switch to short-circuit the line to protect the capacitor.

The exit control technology for short-circuit faults introduces the current quick-break control, the inverse time overcurrent control formulated according to the overcurrent characteristics allowed by the capacitor bank, and the withdrawal of the series compensation capacitor bank is controlled by a fast vacuum switch; it also introduces the overvoltage of the series compensation capacitor bank. Control, by collecting the voltage of the zinc oxide component connected in parallel with the series compensation capacitor bank to directly control the conduction of the bidirectional thyristor, even if the working power supply fails, it will not affect the normal exit of the series compensation capacitor bank.

The alarm and exit control of power failure includes power supply voltage too low, phase loss operation, energy storage capacitor is not fully charged, etc. Two thresholds are set. When the first set threshold is exceeded, a fault alarm signal is sent. When the threshold is set, the battery life function of the working power supply is started, and at the same time, the exit operation of the series compensation capacitor bank is performed, and the storage of the fault information is completed and then enters the "sleep power-saving state".

The alarm and exit control of faults include the alarm and exit control technologies for zinc oxide component failures, series compensation capacitor bank failures, and executive component failures.

The fault identification of zinc oxide components is realized by detecting the leakage current during normal operation. When the first set threshold is exceeded, a fault alarm signal is issued, and when the second set threshold is exceeded, the exit operation of the series compensation capacitor bank is started;

The failure of the series compensation capacitor bank realizes no dead zone protection by collecting the working current, compensation voltage, and bridge differential current, and adopts the fundamental wave impedance and differential current ratio. When the first set threshold is exceeded, a fault alarm signal is issued. When the threshold is reached, the exit operation of the series compensation capacitor bank is started; after the controller sends the opening and closing command, if the delay detects that the state of the fast vacuum switch has not changed, it will send out the "switch position error" alarm signal, and at the same time send out the bidirectional thyristor. through the control pulse.

The basic principles and main features of the present utility model and the advantages of the present utility model have been shown and described above. Those skilled in the art should understand that the utility model is not limited by the above-mentioned embodiments. The above-mentioned embodiments and descriptions only illustrate the principle of the utility model. Without departing from the spirit and scope of the utility model, the utility model The new model also has various changes and improvements, and these changes and improvements all fall within the scope of the claimed utility model. The scope of protection required by the utility model is defined by the appended claims and their equivalents.

Claims (2)

1. the series compensation device based on holographic control strategy, it is characterized in that, including the series compensation capacitor being connected in system line, antivibrator summation current transformer, also including fast vacuum switch, zinc oxide assembly, bidirectional triode thyristor group, voltage collector in parallel, described series compensation capacitor is in parallel with fast vacuum switch, zinc oxide assembly, bidirectional triode thyristor group, voltage collector respectively again after connecting with antivibrator.

2. a kind of series compensation device based on holographic control strategy according to claim 1, it is characterised in that be in series with current collector on the branch road of described zinc oxide assembly.